Polymers are large molecules composed of many repeating structural units. The three main types of polymerization are addition, condensation, and insertion. Addition polymerization involves chain growth where a monomer adds to the end of the growing polymer chain. Condensation polymerization involves step growth where two monomers combine by removing a small molecule. Free radical polymerization is a common type of addition polymerization that uses an initiator to generate free radicals to start the chain reaction.
- Polymers are giant molecules formed by linking together small repeating units called monomers via covalent bonds. There are three main types of polymerization: addition, condensation, and copolymerization.
- Properties of polymers depend on factors like the monomer type, the degree of polymerization, tacticity, and whether the polymer is crystalline or amorphous. Common polymers include polyethylene, polypropylene, nylon, polyethylene terephthalate.
- Natural rubbers are polymers of the monomer isoprene that provide flexibility and elasticity. However, natural rubber has limitations that are overcome through vulcanization, which introduces cross-links between polymer chains through the addition of sulfur.
This document provides an introduction to polymer science, including definitions of key terms like polymer, monomer, oligomer, and degree of polymerization. It discusses various classifications of polymers such as by origin, monomer composition (homopolymer, copolymer), chain structure, configuration, and thermal behavior. Mechanisms of polymerization including step-growth and chain-growth are introduced. Physical properties of polymers related to their structure like crystallinity, glass transition temperature, and elastomers are also covered.
This document discusses polymerization reactions and polymer classification. It begins by defining monomers and polymers, and explaining that polymerization is the chemical reaction where monomers join together via covalent bonds to form polymers. Polymers are classified as homopolymers, copolymers, or by their chain structure. The two main types of polymerization reactions are step-growth and chain-growth polymerization. Step-growth includes condensation polymerization while chain-growth includes addition polymerization. The document provides examples of common polymers formed by different reaction types and ends by discussing applications of polymeric materials.
1. Polymers are large molecules formed by linking together many smaller molecules called monomers. Examples include polyethene formed from linking ethene molecules.
2. Polymers have both crystalline regions that provide strength and amorphous regions that provide flexibility. Their properties depend on their size, shape, and intermolecular forces.
3. Polymers can be classified based on the number of monomers (homo- vs copolymers), the arrangement of monomers (tacticity), functionality (linear, branched, or network), and origin (natural, synthetic, or inorganic).
Copolymerization involves polymerizing two or more different monomers simultaneously so that the resulting polymer contains more than one type of repeating unit in the polymer chain. There are several types of copolymers including random, alternating, block, and graft copolymers. The composition of a copolymer depends on factors like the monomer concentrations and their reactivity ratios. Kinetic models can be used to predict the monomer composition of the copolymer based on the monomer feed using methods like the Mayo-Lewis equation or the Fineman-Ross equation. The reactivity ratios influence whether an ideal random copolymer, alternating copolymer, or block copolymer will form. Ionic copolymerization
The document discusses crystallization and crystallinity of polymers. It defines crystallinity as the degree of structural order in a solid, where the atoms or molecules are arranged in a regular, periodic manner. Crystalline polymers have long-range order arrangement of some segments of polymer chains, while amorphous polymers do not have any degree of crystallinity. Crystallinity depends on factors like length and branching of polymer chains. Methods to evaluate crystallinity include differential scanning calorimetry, X-ray diffraction, infrared spectroscopy, and nuclear magnetic resonance. Crystallinity affects important physical properties of polymers.
The document summarizes various mechanisms of polymerization, including chain-growth polymerization, step-growth polymerization, radical polymerization, cationic polymerization, anionic polymerization, coordination polymerization, Ziegler-Natta catalysis, ring-opening polymerization, and the polymerization of cyclic ethers, cyclic amides, and siloxanes. It discusses reaction initiation, mechanisms, applications, and stereochemistry for different polymerization methods.
Polymers are macromolecules built up by linking together small monomer molecules. There are two types of polymerization mechanisms: step-growth and chain-growth. Step-growth involves monomers and polymers reacting with each other, while chain-growth only involves monomers reacting with active centers on growing polymer chains. Polymers can also be classified based on their structure as linear, branched, or cross-linked, and whether they are thermoplastic or thermoset. Nomenclature of polymers involves naming them based on the monomer source, such as polyethylene from the monomer ethylene.
- Polymers are giant molecules formed by linking together small repeating units called monomers via covalent bonds. There are three main types of polymerization: addition, condensation, and copolymerization.
- Properties of polymers depend on factors like the monomer type, the degree of polymerization, tacticity, and whether the polymer is crystalline or amorphous. Common polymers include polyethylene, polypropylene, nylon, polyethylene terephthalate.
- Natural rubbers are polymers of the monomer isoprene that provide flexibility and elasticity. However, natural rubber has limitations that are overcome through vulcanization, which introduces cross-links between polymer chains through the addition of sulfur.
This document provides an introduction to polymer science, including definitions of key terms like polymer, monomer, oligomer, and degree of polymerization. It discusses various classifications of polymers such as by origin, monomer composition (homopolymer, copolymer), chain structure, configuration, and thermal behavior. Mechanisms of polymerization including step-growth and chain-growth are introduced. Physical properties of polymers related to their structure like crystallinity, glass transition temperature, and elastomers are also covered.
This document discusses polymerization reactions and polymer classification. It begins by defining monomers and polymers, and explaining that polymerization is the chemical reaction where monomers join together via covalent bonds to form polymers. Polymers are classified as homopolymers, copolymers, or by their chain structure. The two main types of polymerization reactions are step-growth and chain-growth polymerization. Step-growth includes condensation polymerization while chain-growth includes addition polymerization. The document provides examples of common polymers formed by different reaction types and ends by discussing applications of polymeric materials.
1. Polymers are large molecules formed by linking together many smaller molecules called monomers. Examples include polyethene formed from linking ethene molecules.
2. Polymers have both crystalline regions that provide strength and amorphous regions that provide flexibility. Their properties depend on their size, shape, and intermolecular forces.
3. Polymers can be classified based on the number of monomers (homo- vs copolymers), the arrangement of monomers (tacticity), functionality (linear, branched, or network), and origin (natural, synthetic, or inorganic).
Copolymerization involves polymerizing two or more different monomers simultaneously so that the resulting polymer contains more than one type of repeating unit in the polymer chain. There are several types of copolymers including random, alternating, block, and graft copolymers. The composition of a copolymer depends on factors like the monomer concentrations and their reactivity ratios. Kinetic models can be used to predict the monomer composition of the copolymer based on the monomer feed using methods like the Mayo-Lewis equation or the Fineman-Ross equation. The reactivity ratios influence whether an ideal random copolymer, alternating copolymer, or block copolymer will form. Ionic copolymerization
The document discusses crystallization and crystallinity of polymers. It defines crystallinity as the degree of structural order in a solid, where the atoms or molecules are arranged in a regular, periodic manner. Crystalline polymers have long-range order arrangement of some segments of polymer chains, while amorphous polymers do not have any degree of crystallinity. Crystallinity depends on factors like length and branching of polymer chains. Methods to evaluate crystallinity include differential scanning calorimetry, X-ray diffraction, infrared spectroscopy, and nuclear magnetic resonance. Crystallinity affects important physical properties of polymers.
The document summarizes various mechanisms of polymerization, including chain-growth polymerization, step-growth polymerization, radical polymerization, cationic polymerization, anionic polymerization, coordination polymerization, Ziegler-Natta catalysis, ring-opening polymerization, and the polymerization of cyclic ethers, cyclic amides, and siloxanes. It discusses reaction initiation, mechanisms, applications, and stereochemistry for different polymerization methods.
Polymers are macromolecules built up by linking together small monomer molecules. There are two types of polymerization mechanisms: step-growth and chain-growth. Step-growth involves monomers and polymers reacting with each other, while chain-growth only involves monomers reacting with active centers on growing polymer chains. Polymers can also be classified based on their structure as linear, branched, or cross-linked, and whether they are thermoplastic or thermoset. Nomenclature of polymers involves naming them based on the monomer source, such as polyethylene from the monomer ethylene.
This document summarizes key aspects of polymer science including polymerization, monomers, and polymerization mechanisms. It discusses that polymerization is the process that links monomer molecules into polymer chains. There are different polymerization mechanisms including chain-growth and free radical polymerization. Chain-growth polymerization proceeds through initiation, propagation, and termination steps. Free radical polymerization uses initiators to generate free radicals to start the polymerization reaction. The document provides examples of monomers and initiators and discusses how functionality of monomers affects the structure of the resulting polymer chains.
This document provides an introduction to polymers. It discusses that polymers are formed through polymerization reactions where small monomer units join together to create large polymer molecules. There are two main types of polymerization - addition and condensation polymerization. Polymers can be classified as homopolymers, formed from one monomer, or copolymers, formed from multiple monomers. The document also discusses important polymer properties like glass transition temperature, molecular weight, types of polymers including thermoplastics and thermosets, and basic mechanical properties.
This document provides an introduction to polymers. Polymers are macromolecules formed by linking many smaller molecules called monomers through a process called polymerization. Polymers can be classified based on their structure as linear, branched or cross-linked. Polymerization occurs through either addition or condensation reactions. Addition polymers are formed without the loss of small molecules, while condensation polymers are formed with the loss of small molecules like water or ammonia. Common examples of addition and condensation polymers are also provided.
Introduction, types, raw material, reaction mechanism, manufacturing process, flow sheet of production process, properties, applications, industries in India, commercial name
This document provides an introduction to polymers including their classification, structure, common types, and mechanisms of polymerization. Polymers are macromolecules composed of repeating structural units connected through polymerization reactions. They can be classified based on their structure as linear, branched, or cross-linked. Common addition polymers include polyethylene, polypropylene, polyvinyl chloride, and nylon. Condensation polymers include polyethylene terephthalate and polyamides. Polymerization occurs primarily through either addition or condensation reactions. Free radical addition polymerization follows initiation, propagation, and termination steps.
Polyester can be produced through various polymerization techniques such as self-condensation, condensation of polyhydroxy compounds with polybasic acids, ester exchange, and ring opening of lactones. Polyester has properties including susceptibility to hydrolysis, proton acceptor ester groups, and increased flexibility. Unsaturated polyester resins are produced from glycols and diacids and provide sites for cross-linking. Polyethylene terephthalate is a widely used polyester produced through ester exchange and polycondensation. It has applications as fibers, films, and bottles. Other polyesters include polybutylene terephthalate and aromatic polyesters.
Miscibility and Thermodynamics of Polymer BlendsAbhinand Krishna
Presentation includes classification of polymer blends based on miscibility, phase diagram of polymer blends and thermodynamics polymer blends which includes Gibbs energy theory and Flory-Huggins Theory
The document discusses various topics related to polymers including their classification, types, mechanisms of polymerization, and methods of polymerization. Polymers can be classified based on their chain structure, chemical composition, source, and backbone. The main types are thermoplastics, thermosets, and elastomers. Polymerization can occur via addition or condensation reactions and methods include bulk, solution, suspension, and emulsion polymerization.
Polymer science deals with large macromolecules made of repeating monomer units. Polymers can be classified in several ways, including by their origin (synthetic, biopolymer, etc.), monomer composition (homopolymer, copolymer like statistical, alternating, block, and graft), chain structure (linear, branched, cross-linked, network), and thermal behavior (thermoplastics and thermosets). Polymerization can occur through step-growth or chain-growth mechanisms. Polymers degrade through various means including chemical, biological, mechanical, chlorine-induced, thermal, and photo degradation which can impact properties like strength, color, and shape over time.
This document discusses polymer science and technology, specifically kinetics and thermodynamics. It covers various topics related to polymer structure, properties, synthesis and characterization. The document contains an outline of chapter topics, including basic principles of polymerization processes, step-reaction polymerization, chain-reaction polymerization, nomenclature of polymers, and examples of industrial polymers like polyethylene, polyvinyl chloride and polystyrene.
Urea formaldehyde is a thermosetting plastic produced from the condensation reaction of urea and formaldehyde. It is commonly used in adhesives, finishes, and particle board. The manufacturing process involves precisely weighing and mixing urea and formaldehyde in an aqueous solution with ammonia as a catalyst. The resulting colorless solution can be spray dried or mixed with fillers. Upon heating and curing, the prepolymers crosslink to form a rigid three-dimensional polymer network. Urea formaldehyde resins have high strength but lower heat resistance compared to other plastics, and releases toxic fumes when heated, though it remains widely used in wood composites and moldings due to its low cost.
This document discusses polymer characteristics and classifications. It defines polymers as long molecules composed of repeating monomer units bonded together, and describes different polymer structures like linear, branched and crosslinked. Polymers are classified as thermoplastics, elastomers or thermosets based on their properties when heated. Thermoplastics can be remelted and reshaped, elastomers stretch and snap back, and thermosets become rigid after forming and cannot be remelted. The document also outlines different polymer synthesis reactions like polycondensation and polyaddition.
Polymer Molecular weight and its Measurement methods.pptxErozgarProfile2227
- There are several methods to measure the average molecular weight of polymers, including end-group analysis, colligative properties, light scattering, and ultracentrifugation.
- The molecular weight distribution and average molecular weights determine important properties like viscosity and processability.
- Common averages include the number-average molecular weight (Mn), weight-average molecular weight (Mw), and viscosity-average molecular weight (Mv). The ratio of Mw/Mn is called the polydispersity index (PDI).
- Techniques like end-group analysis and colligative properties work best for lower molecular weights, while light scattering and ultracentrifugation can measure wider ranges up to 100,
Polymers are macromolecules formed by linking together small repeating units called monomers. There are two main types of polymerization: addition and condensation. Addition polymers are formed without the elimination of small molecules when monomers containing carbon-carbon double bonds polymerize via a chain reaction mechanism involving three steps: initiation, propagation, and termination. Condensation polymers are formed with the elimination of small molecules like water or ammonia when bifunctional monomers react. Common examples of addition polymerization include polyethylene formed from ethylene monomers using a free radical initiator like benzoyl peroxide.
Condensation polymerization involves monomers with functional groups like alcohols and carboxylic acids. During condensation polymerization, these functional groups react to form polymer chains, releasing small molecules like water or methanol as byproducts. This results in strong covalent bonds between the monomers, such as amide or ester linkages. Common examples of condensation polymerization are the reaction of a carboxylic acid and amine to form an amide linkage, or a carboxylic acid and alcohol to form an ester linkage. Condensation polymerization is an important process that allows for the production of many plastics and other materials.
Determining molecular weights of polymers is important because it controls properties like solubility, elasticity, and mechanics. Polymers do not have uniform molecular weights but a distribution of different sizes. Molecular weight can be determined through various physical and chemical methods like end group analysis, light scattering, viscosity measurements, and gel permeation chromatography. These methods provide information about the number average molecular weight and distribution across molecules in a sample.
Polymer behaviour in solution & effect of molecular weight in polymerSyed Minhazur Rahman
Polymer chains of varying molecular weights exhibit different behaviors in solution. Higher molecular weight polymers swell more before dissolving and produce highly viscous solutions even at low concentrations. Their long, entangled chains confer properties like high strength, impact resistance, and chemical resistance. Lower molecular weight polymers dissolve immediately and yield low viscosity solutions. Their short chains act as plasticizers and impart softness, flexibility, and increased molecular mobility. A polymer's molecular weight determines the length of its chains and significantly impacts its solution behavior and material properties.
The presentation gives a brief idea about polymers,its definition,types of polymers,common examples of polymers,polymerization and its types,polymer processing and applications of polymers.
Emulsion polymerization involves radical chain polymerization where monomers are dispersed as droplets in water and polymerize within micelles. It allows for high molecular weight polymers to form at high reaction rates. The process involves four main components: 1) monomers, 2) a dispersion medium (water), 3) an emulsifier, and 4) a water-soluble initiator. Polymerization occurs only within the micelles. The mechanism proceeds in three stages: initiation within the micelles, monomer diffusion into particles as conversion increases, and consumption of monomer droplets. Emulsion polymerization produces polymer latex particles and addresses heat transfer and viscosity issues relative to other polymerization methods.
This document provides an overview of polymer chemistry course content including synthesis of polymers, characterization of polymer molecules, molecular weight determination, and polymer structures. It discusses different types of polymers such as thermoplastics, thermosets, elastomers, and their properties. The key topics covered are polymerization reactions, molecular weight averages, polymer configurations including isotactic, syndiotactic and atactic, nomenclature, and the importance of molecular weight on polymer properties.
The document discusses polymers including their classification, types of polymerization, characteristics, and applications. Polymers can be classified based on source, structure, polymerization method, and molecular forces. There are two main types of polymerization - addition and condensation. Polymers have characteristics like low density, corrosion resistance, and moldability. They have wide applications in medicine, consumer products, industry, and sports equipment.
This document summarizes key aspects of polymer science including polymerization, monomers, and polymerization mechanisms. It discusses that polymerization is the process that links monomer molecules into polymer chains. There are different polymerization mechanisms including chain-growth and free radical polymerization. Chain-growth polymerization proceeds through initiation, propagation, and termination steps. Free radical polymerization uses initiators to generate free radicals to start the polymerization reaction. The document provides examples of monomers and initiators and discusses how functionality of monomers affects the structure of the resulting polymer chains.
This document provides an introduction to polymers. It discusses that polymers are formed through polymerization reactions where small monomer units join together to create large polymer molecules. There are two main types of polymerization - addition and condensation polymerization. Polymers can be classified as homopolymers, formed from one monomer, or copolymers, formed from multiple monomers. The document also discusses important polymer properties like glass transition temperature, molecular weight, types of polymers including thermoplastics and thermosets, and basic mechanical properties.
This document provides an introduction to polymers. Polymers are macromolecules formed by linking many smaller molecules called monomers through a process called polymerization. Polymers can be classified based on their structure as linear, branched or cross-linked. Polymerization occurs through either addition or condensation reactions. Addition polymers are formed without the loss of small molecules, while condensation polymers are formed with the loss of small molecules like water or ammonia. Common examples of addition and condensation polymers are also provided.
Introduction, types, raw material, reaction mechanism, manufacturing process, flow sheet of production process, properties, applications, industries in India, commercial name
This document provides an introduction to polymers including their classification, structure, common types, and mechanisms of polymerization. Polymers are macromolecules composed of repeating structural units connected through polymerization reactions. They can be classified based on their structure as linear, branched, or cross-linked. Common addition polymers include polyethylene, polypropylene, polyvinyl chloride, and nylon. Condensation polymers include polyethylene terephthalate and polyamides. Polymerization occurs primarily through either addition or condensation reactions. Free radical addition polymerization follows initiation, propagation, and termination steps.
Polyester can be produced through various polymerization techniques such as self-condensation, condensation of polyhydroxy compounds with polybasic acids, ester exchange, and ring opening of lactones. Polyester has properties including susceptibility to hydrolysis, proton acceptor ester groups, and increased flexibility. Unsaturated polyester resins are produced from glycols and diacids and provide sites for cross-linking. Polyethylene terephthalate is a widely used polyester produced through ester exchange and polycondensation. It has applications as fibers, films, and bottles. Other polyesters include polybutylene terephthalate and aromatic polyesters.
Miscibility and Thermodynamics of Polymer BlendsAbhinand Krishna
Presentation includes classification of polymer blends based on miscibility, phase diagram of polymer blends and thermodynamics polymer blends which includes Gibbs energy theory and Flory-Huggins Theory
The document discusses various topics related to polymers including their classification, types, mechanisms of polymerization, and methods of polymerization. Polymers can be classified based on their chain structure, chemical composition, source, and backbone. The main types are thermoplastics, thermosets, and elastomers. Polymerization can occur via addition or condensation reactions and methods include bulk, solution, suspension, and emulsion polymerization.
Polymer science deals with large macromolecules made of repeating monomer units. Polymers can be classified in several ways, including by their origin (synthetic, biopolymer, etc.), monomer composition (homopolymer, copolymer like statistical, alternating, block, and graft), chain structure (linear, branched, cross-linked, network), and thermal behavior (thermoplastics and thermosets). Polymerization can occur through step-growth or chain-growth mechanisms. Polymers degrade through various means including chemical, biological, mechanical, chlorine-induced, thermal, and photo degradation which can impact properties like strength, color, and shape over time.
This document discusses polymer science and technology, specifically kinetics and thermodynamics. It covers various topics related to polymer structure, properties, synthesis and characterization. The document contains an outline of chapter topics, including basic principles of polymerization processes, step-reaction polymerization, chain-reaction polymerization, nomenclature of polymers, and examples of industrial polymers like polyethylene, polyvinyl chloride and polystyrene.
Urea formaldehyde is a thermosetting plastic produced from the condensation reaction of urea and formaldehyde. It is commonly used in adhesives, finishes, and particle board. The manufacturing process involves precisely weighing and mixing urea and formaldehyde in an aqueous solution with ammonia as a catalyst. The resulting colorless solution can be spray dried or mixed with fillers. Upon heating and curing, the prepolymers crosslink to form a rigid three-dimensional polymer network. Urea formaldehyde resins have high strength but lower heat resistance compared to other plastics, and releases toxic fumes when heated, though it remains widely used in wood composites and moldings due to its low cost.
This document discusses polymer characteristics and classifications. It defines polymers as long molecules composed of repeating monomer units bonded together, and describes different polymer structures like linear, branched and crosslinked. Polymers are classified as thermoplastics, elastomers or thermosets based on their properties when heated. Thermoplastics can be remelted and reshaped, elastomers stretch and snap back, and thermosets become rigid after forming and cannot be remelted. The document also outlines different polymer synthesis reactions like polycondensation and polyaddition.
Polymer Molecular weight and its Measurement methods.pptxErozgarProfile2227
- There are several methods to measure the average molecular weight of polymers, including end-group analysis, colligative properties, light scattering, and ultracentrifugation.
- The molecular weight distribution and average molecular weights determine important properties like viscosity and processability.
- Common averages include the number-average molecular weight (Mn), weight-average molecular weight (Mw), and viscosity-average molecular weight (Mv). The ratio of Mw/Mn is called the polydispersity index (PDI).
- Techniques like end-group analysis and colligative properties work best for lower molecular weights, while light scattering and ultracentrifugation can measure wider ranges up to 100,
Polymers are macromolecules formed by linking together small repeating units called monomers. There are two main types of polymerization: addition and condensation. Addition polymers are formed without the elimination of small molecules when monomers containing carbon-carbon double bonds polymerize via a chain reaction mechanism involving three steps: initiation, propagation, and termination. Condensation polymers are formed with the elimination of small molecules like water or ammonia when bifunctional monomers react. Common examples of addition polymerization include polyethylene formed from ethylene monomers using a free radical initiator like benzoyl peroxide.
Condensation polymerization involves monomers with functional groups like alcohols and carboxylic acids. During condensation polymerization, these functional groups react to form polymer chains, releasing small molecules like water or methanol as byproducts. This results in strong covalent bonds between the monomers, such as amide or ester linkages. Common examples of condensation polymerization are the reaction of a carboxylic acid and amine to form an amide linkage, or a carboxylic acid and alcohol to form an ester linkage. Condensation polymerization is an important process that allows for the production of many plastics and other materials.
Determining molecular weights of polymers is important because it controls properties like solubility, elasticity, and mechanics. Polymers do not have uniform molecular weights but a distribution of different sizes. Molecular weight can be determined through various physical and chemical methods like end group analysis, light scattering, viscosity measurements, and gel permeation chromatography. These methods provide information about the number average molecular weight and distribution across molecules in a sample.
Polymer behaviour in solution & effect of molecular weight in polymerSyed Minhazur Rahman
Polymer chains of varying molecular weights exhibit different behaviors in solution. Higher molecular weight polymers swell more before dissolving and produce highly viscous solutions even at low concentrations. Their long, entangled chains confer properties like high strength, impact resistance, and chemical resistance. Lower molecular weight polymers dissolve immediately and yield low viscosity solutions. Their short chains act as plasticizers and impart softness, flexibility, and increased molecular mobility. A polymer's molecular weight determines the length of its chains and significantly impacts its solution behavior and material properties.
The presentation gives a brief idea about polymers,its definition,types of polymers,common examples of polymers,polymerization and its types,polymer processing and applications of polymers.
Emulsion polymerization involves radical chain polymerization where monomers are dispersed as droplets in water and polymerize within micelles. It allows for high molecular weight polymers to form at high reaction rates. The process involves four main components: 1) monomers, 2) a dispersion medium (water), 3) an emulsifier, and 4) a water-soluble initiator. Polymerization occurs only within the micelles. The mechanism proceeds in three stages: initiation within the micelles, monomer diffusion into particles as conversion increases, and consumption of monomer droplets. Emulsion polymerization produces polymer latex particles and addresses heat transfer and viscosity issues relative to other polymerization methods.
This document provides an overview of polymer chemistry course content including synthesis of polymers, characterization of polymer molecules, molecular weight determination, and polymer structures. It discusses different types of polymers such as thermoplastics, thermosets, elastomers, and their properties. The key topics covered are polymerization reactions, molecular weight averages, polymer configurations including isotactic, syndiotactic and atactic, nomenclature, and the importance of molecular weight on polymer properties.
The document discusses polymers including their classification, types of polymerization, characteristics, and applications. Polymers can be classified based on source, structure, polymerization method, and molecular forces. There are two main types of polymerization - addition and condensation. Polymers have characteristics like low density, corrosion resistance, and moldability. They have wide applications in medicine, consumer products, industry, and sports equipment.
Introduction to pharmaceuitcal polymer chemistryGanesh Mote
The document discusses various types of polymers including their structure, properties, and uses. It defines a polymer as a large molecule formed by the repeated linking of small molecules called monomers. Polymers can be classified based on their source, structure, molecular forces, and mode of polymerization. Common polymers discussed include polyethylene, polypropylene, polystyrene, polyvinyl chloride, teflon, and poly(methyl methacrylate). Their properties and applications in various industries are also summarized.
Polymers are long chains of repeating molecular units called monomers. There are several types of polymers including polyethene, polypropene, nylons, polyurethanes, and polyesters. Polymers are classified based on their structure and production method. Properties depend on factors like chain length and structure. Common applications include plastic containers, clothing, pipes, sports equipment, and medical devices.
Polymer science: preparation and uses of polymersVARSHAAWASAR
Polymers are large molecules formed by combining many smaller molecules called monomers. They are made through polymerization reactions where monomers join together in chains. There are two main types of polymerization - addition and condensation. Polymers have a wide variety of applications including plastics, fibers, elastomers and more. Their properties depend on factors like molecular structure and weight. Thermal analysis techniques are used to characterize polymers and determine properties like glass transition temperature. Biodegradable polymers break down over time and have applications in drug delivery.
This document provides an introduction to polymers for A-level chemistry students. It discusses the two main types of polymerization: addition and condensation. Addition polymerization involves monomers joining together with all atoms incorporated into the polymer chain. Condensation polymerization involves monomers joining together with the elimination of small molecules, so not all original atoms are present. Common examples of addition and condensation polymers are discussed, along with their properties and uses.
Polymer properties and characterisationArchana Nair
This document discusses various techniques used to characterize polymers. It begins with an introduction to polymers and their properties. It then describes several techniques including molecular weight determination using methods like light scattering and gel permeation chromatography. It also discusses vibrational spectroscopy using infrared and Raman spectroscopy. Other techniques covered include nuclear magnetic resonance spectroscopy, microscopy, thermal analysis, x-ray diffraction, and mechanical and rheological analyses. The document provides information on analyzing various properties of polymers including molecular structure, crystallinity, glass transition temperature, and viscoelastic behavior.
Polymer materials are long chain molecules made of repeating monomer units. They include plastics, rubbers, and fibers. Polymers are classified as thermoplastics, thermosets, homopolymers, copolymers, and natural polymers. The structure and properties of polymers depend on factors like chain length, branching, and cross-linking. Polymers have a variety of applications including packaging, insulation, automotive and medical parts due to their low cost, low density, and moldability.
Fine tuning template radical polymerization in micellar nanoreactorsLim Dong Quan
1. The document investigates the effect of micellar core size and overall micelle size on template radical polymerization of vinylbenzyl adenine (VBA) using poly(styrene-b-vinylbenzyl thymine) (PSt-b-PVBT) block copolymers as templates.
2. Various PSt-b-PVBT copolymers were synthesized with different PVBT block lengths and overall molecular weights to control the micellar core size and overall micelle size. Dynamic light scattering showed the micellar core size was similar at around 45 nm for most templates.
3. Template polymerization of VBA yielded daughter polymers with ultrahigh molecular weights over
This document discusses the benefits of exercise for both physical and mental health. It states that regular exercise can improve cardiovascular health, reduce symptoms of depression and anxiety, enhance mood, and reduce stress levels. The document also mentions that even moderate exercise for 30 minutes per day can result in these benefits.
This document introduces Polymer, an open-source JavaScript library for building web components. It discusses how Polymer uses existing web platform APIs like templates, shadow DOM, and custom elements to create reusable components. It also explains that Polymer is not a framework, but a library that can be used to build elements on top of existing standards. Finally, it provides a simple example of creating a new custom element in Polymer and emphasizes that Polymer is production-ready.
Polybutadiene is a synthetic rubber polymerized from the monomer 1,3-butadiene. It was first synthesized in 1910 and accounts for about a quarter of global synthetic rubber production, with around 70% used in tire manufacturing. Polybutadiene can be produced through various polymerization methods and processed through techniques like injection molding. It has good abrasion resistance and flexibility but poor resistance to oil and gasoline. Research articles discussed using sepiolite nanofibers to improve the mechanical properties of polybutadiene rubber composites and emulsion polymerization methods to synthesize polybutadiene nanoparticles. In conclusion, polybutadiene will continue to be widely used in tires and other applications due to its
1 s2.0-s037838121100207 x-main.correlation of thermodynamic modeling and mole...Josemar Pereira da Silva
The document describes a method for correlating thermodynamic modeling and molecular simulations to predict liquid-liquid equilibrium in ternary polymer mixtures. The method uses a modified double lattice theory thermodynamic model combined with molecular simulations to determine interaction energy parameters. Dummy atoms are used to represent polymer segments in the simulations. The method is applied to four real ternary polymer systems, with the energy parameters directly used in the thermodynamic model. The results show good agreement with experimental observations using one or no adjustable parameters.
2 the kinetic of emulsion polymerisationAdzagaAnton
The document discusses the kinetics of emulsion polymerization. It begins with an overview of polymerization techniques and the basic principles of emulsion polymerization, including the role of micelles and monomer droplets.
It then provides more details on the generally accepted kinetics scheme of particle formation and growth. Radical entry into micelles can occur through either diffusion-controlled or propagation-controlled mechanisms. Radical desorption (exit) from particles and its effects on particle growth in homopolymer and copolymer systems are also reviewed.
The kinetics and mechanisms of various stages of emulsion polymerization are examined in depth, including particle formation, particle growth models for homopolymers and copolymers, and monomer concentration within
This document provides information on polymers and plastics. It defines a polymer as being made up of chains of many links. Plastics are polymers where the chains come together to form long chains. The simplest example given is polyethylene, made from ethylene molecules reacting to form chains. Polymers can be made into various products like plastic bottles, sleeping bags, and eyeglasses. The document discusses polymer properties, types including thermoplastics and thermosets, and synthesis methods like chain polymerization. It also covers topics like polymer crystallization, glass transition temperatures, solvent interactions, processing methods like extrusion, and blending of polymers.
This document discusses common features and functions for working with application software in Windows, including how to start and exit programs, work with application windows, switch between open windows, use menus and toolbars, open and save files, change application settings, and access help. Specifically, it covers starting programs from the Start menu or desktop icons, closing programs using the Close button, components of application windows like the title bar and scroll bars, switching between windows using the taskbar, navigating menus and toolbars, opening the ribbon interface in Microsoft Office 2010, and obtaining help directly from the application or online resources.
The document discusses radical chain polymerization, specifically free radical polymerization. It covers the basic mechanisms of initiation, propagation, and termination in free radical polymerization as well as factors that influence these steps such as monomer structure, initiator type, and chain transfer reactions. Chain transfer reactions are described as terminating the growing polymer chain and starting a new chain. The document provides examples of different initiator types and monomers that undergo free radical polymerization.
Polymers are large molecules formed by chemical bonding of many smaller molecules called monomers. There are two main types of polymers: thermoplastics and thermosets. Thermoplastics can be remelted and reshaped, while thermosets harden permanently after heating. Common polymerization reactions include bulk, suspension, solution, and emulsion polymerization. Biodegradable polymers break down into natural byproducts, while bioplastics are made from renewable sources. Polymer properties depend on factors like tacticity, polydispersity index, and glass transition temperature. Examples of important polymers include polyethylene, nylon, polyesters, PVC, Teflon, and conducting polymers.
This document provides an overview of polymers including their types, classifications, characteristics, and applications. It defines polymers as large molecules formed from monomers linking together in chains. Polymers are classified based on their origin, structure, and mode of polymerization. Some key types discussed are natural, homo, co, thermoset, and thermoplastic polymers. Common characteristics include low density, moldability and poor strength. Finally, applications highlighted are in medicine, consumer products, industry, and sports equipment.
This document provides an overview of polymers including their types, classifications, characteristics, and applications. It defines polymers as large molecules formed from monomers linking together in chains. Polymers are classified based on their origin, structure, and mode of polymerization. Some key types discussed are natural, homo, co, thermoset, and thermoplastic polymers. Common characteristics include low density, corrosion resistance, and moldability. Finally, applications highlighted are in medicine, consumer products, industry, and sports equipment.
Polymers play a very important role in human life. Our body is made of lot of polymers, e.g. Proteins, enzymes, etc. Other naturally occurring polymers like wood, rubber, leather and silk are have wide application. Now a day synthetic polymer like useful plastics, rubbers and fiber materials are synthesized. presentation includes introduction classification and preparation methods. Polymers play a very important role in human life. Our body is made of lot of polymers, e.g. Proteins, enzymes, etc. Other naturally occurring polymers like wood, rubber, leather and silk are have wide application. Now a day synthetic polymer like useful plastics, rubbers and fiber materials are synthesized. Leo Baekeland patented the first totally synthetic polymer called Bakelite (1910). Bakelite is a versatile, durable material prepared from low-cost materials phenol and formaldehyde and was the most important synthetic polymer material. In the 1920s Hermann Staudinger showed that polymers were high-molecular-weight compounds held together by normal covalent bonds.
The suffix in polymer ‘mer’ is originated from Greek word meros – which means part. The word polymer is thus coined to mean material consisting of many parts or mers. A macromolecule having high molecular mass (103-107u) and generally not a well-defined structure or molecular weight. The macromolecules formed by joining of repeating structural units on a large scale. The repeating structural units are simple and reactive molecules linked to each other by covalent bonds. This process of formation of polymers from respective monomers is called polymerization. Most of the polymers are basically organic compounds, however they can be inorganic (e.g. silicones based on Si-O network).
Basic Terms : Macromolecule, Monomer , Repeat Unit, Classification of polymers based on Origin, thermal response Polymerisation , Addition and condensation , Degree of Polymerisation, Polymer Structures - Linear , Branched and Cross-linked. Molecular weight of Polymers: Definition and Formulae of Number Average Molecular Weight , Weight Average Molecular weight, Viscosity Average Molecular Weight , Z-average Molecular Weight. Polydispersity Index
This document discusses dental bio-materials, specifically polymers. It defines polymers as long chain molecules made of repeating monomer units. Polymers are classified based on their origin, polymerization reaction, and structural configuration. Common polymers discussed include PMMA, nylon, and polyethylene. The stages of addition polymerization - initiation, propagation, and termination - are explained in detail. Factors that influence polymer properties and techniques like co-polymerization are also summarized.
This document provides information on the objectives and outcomes of chemistry courses related to materials chemistry, polymers, and elastomers. The courses aim to help students correlate material properties with internal structure, apply principles of electrochemistry and corrosion prevention, and discuss different types of polymers for engineering applications. Specific topics covered include polymerization reactions, polyvinyl chloride, bakelite, nylon-6,6, Kevlar, and elastomers. After completing the courses, students will be able to analyze and apply concepts related to batteries, water treatment, corrosion prevention, and different types of polymers and their uses.
The document discusses polymers and their characteristics. It defines polymers as large molecules composed of repeating structural units called monomers. There are two main types of polymerization - addition polymerization and condensation polymerization. Addition polymerization involves monomers adding together in chains, while condensation polymerization involves monomers condensing together with a byproduct. Polymers can be natural or synthetic, organic or inorganic, and used for various applications like plastics, fibers, and adhesives depending on their structure and properties.
This document provides information about polymers and polymerization. It defines a polymer as a long molecule formed by joining thousands of small monomer units through chemical bonds. The degree of polymerization refers to the number of repeating monomer units in the polymer chain. Polymers can be classified based on their source, structure, tacticity, monomer units, end uses, conductance, environmental impact, and behavior when heated. The two main types of polymerization are addition polymerization and condensation polymerization. Examples of daily use polymers like polyethylene, polyvinyl chloride, nylon, bakelite etc. are also discussed along with their properties and applications.
Polymers are large molecules formed by combining many small molecules called monomers. There are two main types of polymerization: addition and condensation. Addition polymers form without releasing any byproducts while condensation polymers form with the release of small molecules like water. Polymers can be classified based on their source, structure, and thermal properties. Common polymerization techniques include bulk, solution, suspension, and emulsion which depend on factors like physical state and reaction mechanism. Bulk polymerization involves only monomer and initiator while solution polymerization dissolves the monomer in a solvent.
The document discusses various types of polymers including thermoplastics like polyethylene, polypropylene, polyvinyl chloride, polystyrene; thermosetting plastics; polymerization methods like addition, condensation and their mechanisms; classification of polymers; properties and applications of common polymers like polyethylene, polystyrene, polyvinyl chloride and teflon. It also discusses polymer structure, degree of polymerization, tactics and various additives used in plastics.
Polymer chemistry involves the study of polymers, which are large molecules composed of many repeating structural units connected by covalent bonds. The monomers that make up polymers are linked through polymerization reactions. Polymers can be classified based on their structure, source, number of monomers, arrangement of monomers, and configuration. Common types of polymers include linear, branched, and cross-linked polymers. Polymers are also classified as natural, semi-synthetic, or synthetic based on their source. Polymerization reactions are either addition polymerization, involving chain growth, or condensation polymerization, involving step growth. Important conducting polymers include intrinsically conducting polymers and extrinsically conducting polymers. Biopolymers include nucleic acids, proteins,
Polymer chemistry involves the study of polymers, which are large molecules composed of many repeating structural units connected by covalent bonds. The monomers that make up polymers are linked through polymerization reactions. Polymers can be classified based on their structure, source, number of monomers, arrangement of monomers, and configuration. Common types of polymers include linear, branched, and cross-linked polymers. Polymers are also classified as natural, semi-synthetic, or synthetic based on their source. Polymerization reactions are either addition polymerization, involving chain growth, or condensation polymerization, involving step growth. Polymers have a variety of applications and properties depending on their structure and bonding forces.
Polymers are macromolecules formed by combining many small molecules (monomers) through covalent bonds. Common examples include polyethylene, polypropylene, polyvinyl chloride, nylon, and rubber. Polymers can be classified based on their source (natural, semi-synthetic, synthetic), structure (linear, branched, cross-linked), or the polymerization process used to create them (addition, condensation). Polymerization involves monomers combining in chains through addition or condensation reactions with or without the loss of small molecules as byproducts. The type of polymerization determines the properties and applications of the resulting polymers.
This document discusses polymers, including their classification, types of polymerization, characteristics, and applications. Polymers can be classified based on their source, structure, polymerization method, or molecular forces. The main types of polymerization are addition and condensation. Polymers have properties like low density, corrosion resistance, and moldability. They are used widely in applications such as medicine, consumer products, industry, and sports equipment.
This document discusses polymers, including their classification, characteristics, properties, strengths, and applications. It begins with an introduction to polymers being long chains of repeating monomer units. It then covers the main topics of types of polymers like polyethene and nylon, how they are classified based on composition and reaction, their characteristics like low density and good moldability. Properties depend on chain length and structure. Strength increases with longer chains and higher crystallinity. Finally, applications of polymers in areas like packaging, textiles, construction, medicine and pharmaceuticals are outlined.
Polymer science concerns large molecules called polymers that include rubbers, plastics, and fibers. Polymers are made of repeating molecular units and have high molecular weights. There are over 60,000 scientists working with polymers today to develop new materials with customized properties. Common polymers include polypropylene, polyethylene, and nylons. Polymers can be categorized based on their molecular structure as thermoplastics, thermosets, or elastomers, which determine how they respond to heat.
Polymers are large molecules formed by combining many smaller subunits called monomers. They can be found naturally or made synthetically. Polymers are formed through polymerization reactions where monomers bond together into long chains or networks. There are several ways polymers can be classified, including by their source, structure, type of polymerization reaction, monomers used, intermolecular forces, backbone composition, and atomic arrangement. The functionality and degree of polymerization also provide information about polymers' structure and properties.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
2. PolymersPolymers
What is a polymer?What is a polymer?
Very Large molecules structures chain-like inVery Large molecules structures chain-like in
nature.nature.
PolyPoly mermer
manymany repeat unitrepeat unit
Adapted from Fig. 14.2, Callister 7e.
C C C C C C
HHHHHH
HHHHHH
Polyethylene (PE)
ClCl Cl
C C C C C C
HHH
HHHHHH
Polyvinyl chloride (PVC)
HH
HHH H
Polypropylene (PP)
C C C C C C
CH3
HH
CH3CH3 H
repeat
unit
repeat
unit
repeat
unit
3. Ancient Polymer HistoryAncient Polymer History
Originally natural polymers were usedOriginally natural polymers were used
WoodWood – Rubber– Rubber
CottonCotton – Wool– Wool
LeatherLeather – Silk– Silk
4. Polymer CompositionPolymer Composition
Most polymers are hydrocarbonsMost polymers are hydrocarbons
–– i.e. made up of H and Ci.e. made up of H and C
Saturated hydrocarbonsSaturated hydrocarbons
Each carbon bonded to four other atomsEach carbon bonded to four other atoms
CCnnHH2n+22n+2
C C
H
H H
H
H
H
5.
6. Unsaturated HydrocarbonsUnsaturated Hydrocarbons
Double & triple bonds relatively reactive – can formDouble & triple bonds relatively reactive – can form
new bondsnew bonds
Double bondDouble bond – ethylene or ethene - C– ethylene or ethene - CnnHH2n2n
C C
H
H
H
H
8. Unsaturated HydrocarbonsUnsaturated Hydrocarbons
AnAn aromatic hydrocarbonaromatic hydrocarbon (abbreviated(abbreviated
as AH) oras AH) or arenearene is a hydrocarbon, ofis a hydrocarbon, of
which the molecular structure incorporateswhich the molecular structure incorporates
one or more planar sets of six carbonone or more planar sets of six carbon
atoms that are connected by delocalisedatoms that are connected by delocalised
electrons numbering the same as if theyelectrons numbering the same as if they
consisted of alternating single and doubleconsisted of alternating single and double
covalent bondscovalent bonds
10. Unsaturated HydrocarbonsUnsaturated Hydrocarbons
What is actually found is that all of theWhat is actually found is that all of the
bond lengths in the benzene rings arebond lengths in the benzene rings are
1.397 angstroms1.397 angstroms
This is roughly intermediate between theThis is roughly intermediate between the
typical lengths of single bonds (~1.5typical lengths of single bonds (~1.5
angstroms) and double bonds (~1.3angstroms) and double bonds (~1.3
angstroms)angstroms)
11. IsomerismIsomerism
IsomerismIsomerism
two compounds with same chemical formula cantwo compounds with same chemical formula can
have quite different structures/atomic arrangementhave quite different structures/atomic arrangement
Ex: CEx: C88HH1818
n-octanen-octane
2-methyl-4-ethyl pentane (isooctane)2-methyl-4-ethyl pentane (isooctane)
C C C C C C C CH
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H H3C CH2 CH2 CH2 CH2 CH2 CH2 CH3=
H3C CH
CH3
CH2 CH
CH2
CH3
CH3
H3C CH2 CH3( )
6
⇓
12. Chemistry of PolymersChemistry of Polymers
Free radical polymerizationFree radical polymerization
InitiatorInitiator: example - benzoyl peroxide: example - benzoyl peroxide
C
H
H
O O C
H
H
C
H
H
O2
C C
H H
HH
monomer
(ethylene)
R +
free radical
R C C
H
H
H
H
initiation
R C C
H
H
H
H
C C
H H
HH
+ R C C
H
H
H
H
C C
H H
H H
propagation
dimer
R= 2
13. Chemistry of PolymersChemistry of Polymers
Adapted from Fig.
14.1, Callister 7e.
Note: polyethylene is just a long HC
- paraffin is short polyethylene
18. Range of PolymersRange of Polymers
Traditionally, the industry has producedTraditionally, the industry has produced
two main types of synthetic polymer –two main types of synthetic polymer –
plastics and rubbers.plastics and rubbers.
Plastics are (generally) rigid materials atPlastics are (generally) rigid materials at
service temperaturesservice temperatures
Rubbers are flexible, low modulusRubbers are flexible, low modulus
materials which exhibit long-rangematerials which exhibit long-range
elasticity.elasticity.
19. Range of PolymersRange of Polymers
Plastics are further subdivided intoPlastics are further subdivided into
thermoplastics and thermosetsthermoplastics and thermosets
22. Range of PolymersRange of Polymers
Another way of classifying polymers is inAnother way of classifying polymers is in
terms of their form or functionterms of their form or function
24. Synthesis of PolymersSynthesis of Polymers
There are a number different methodsThere are a number different methods
of preparing polymers from suitableof preparing polymers from suitable
monomers, these aremonomers, these are
step-growth (or condensation)step-growth (or condensation)
polymerisationpolymerisation
addition polymerisationaddition polymerisation
insertion polymerisation.insertion polymerisation.
25. Types of PolymerizationTypes of Polymerization
Chain-growth polymers, also known as
addition polymers, are made by chain
reactions
26. Types of PolymerizationTypes of Polymerization
Step-growth polymers, also called
condensation polymers, are made by
combining two molecules by removing a
small molecule
27. Addition Vs. CondensationAddition Vs. Condensation
PolymerizationPolymerization
Polymerisation reactions can generally bePolymerisation reactions can generally be
written aswritten as
x-mer + y-merx-mer + y-mer (x +y)-mer(x +y)-mer
In a reaction that leads toIn a reaction that leads to condensationcondensation
polymerspolymers, x and y may assume any value, x and y may assume any value
i.e. chains of any size may react togetheri.e. chains of any size may react together
as long as they are capped with theas long as they are capped with the
correct functional groupcorrect functional group
28. Addition Vs. CondensationAddition Vs. Condensation
PolymerizationPolymerization
InIn addition polymerizationaddition polymerization although xalthough x
may assume any value, y is confined tomay assume any value, y is confined to
unityunity
i.e. the growing chain can react only with ai.e. the growing chain can react only with a
monomer molecule and continue itsmonomer molecule and continue its
growthgrowth
29. ThermodynamicsThermodynamics
Thermodynamics of polymerizationThermodynamics of polymerization
determines the position of the equilibriumdetermines the position of the equilibrium
between polymer and monomer(s).between polymer and monomer(s).
The well known thermodynamicThe well known thermodynamic
expression:expression:
∆∆G =G = ∆∆H - TH - T∆∆SS
yields the basis for understandingyields the basis for understanding
polymerization/depolymerization behavior.polymerization/depolymerization behavior.
30. ThermodynamicsThermodynamics
For polymerization to occur (i.e., to beFor polymerization to occur (i.e., to be
thermodynamically feasible), the Gibbsthermodynamically feasible), the Gibbs
free energy of polymerizationfree energy of polymerization ∆∆GGpp < 0< 0..
IfIf ∆∆GGpp > 0> 0, then depolymerization will be, then depolymerization will be
favored.favored.
31. ThermodynamicsThermodynamics
Standard enthalpy and entropy changes,Standard enthalpy and entropy changes,
∆∆HHoo
p andp and ∆∆SSoo
p are reported for reactantsp are reported for reactants
and products in their appropriate standardand products in their appropriate standard
states. Generally:states. Generally:
Temperature = 25Temperature = 25oo
C = 298KC = 298K
Monomer – pure, bulk monomer or 1 MMonomer – pure, bulk monomer or 1 M
solutionsolution
Polymer – solid amorphous or slightlyPolymer – solid amorphous or slightly
crystallinecrystalline
32. ThermodynamicsThermodynamics
Polymerization is an association reactionPolymerization is an association reaction
such that many monomers associate tosuch that many monomers associate to
form the polymerform the polymer
Thus:Thus: ∆∆Sp < 0 for nearly all polymerizationSp < 0 for nearly all polymerization
processesprocesses
33. ThermodynamicsThermodynamics
Since depolymerization is almost alwaysSince depolymerization is almost always
entropicallyentropically favored, thefavored, the ∆∆HHpp must then bemust then be
sufficientlysufficiently negativenegative to compensate for theto compensate for the
unfavorable entropic term.unfavorable entropic term.
Only then will polymerization beOnly then will polymerization be
thermodynamically favored by thethermodynamically favored by the
resulting negativeresulting negative ∆∆Gp.Gp.
34. ThermodynamicsThermodynamics
In practice:In practice:
Polymerization is favored at lowPolymerization is favored at low
temperatures: Ttemperatures: T∆∆Sp is smallSp is small
Depolymerization is favored at highDepolymerization is favored at high
temperatures: Ttemperatures: T∆∆Sp is largeSp is large
35. ThermodynamicsThermodynamics
Therefore, thermal instability of polymersTherefore, thermal instability of polymers
results whenresults when TT∆∆SSpp overridesoverrides ∆∆HHpp and thusand thus
∆∆GGpp > O> O; this causes the system to; this causes the system to
spontaneously depolymerize (spontaneously depolymerize (if kineticif kinetic
pathway existspathway exists).).
36. ThermodynamicsThermodynamics
the activation energy for thethe activation energy for the
depropagation reaction is higher,depropagation reaction is higher,
Compared to the propagation reaction itsCompared to the propagation reaction its
rate increases more with increasingrate increases more with increasing
temperaturetemperature
As shown below, this results in a ceilingAs shown below, this results in a ceiling
temperature.temperature.
37. ThermodynamicsThermodynamics
ceiling temperatureceiling temperature
the temperature at which the propagation andthe temperature at which the propagation and
depropagation reaction rates are exactlydepropagation reaction rates are exactly
equal at a given monomer concentrationequal at a given monomer concentration
300 350 400 450 500 550 600
0
1
2
3
4
5
6
Tc
kp
[M] - kdp
kp
[M]
kdp
k,sec
-1
Temperature,
o
K
38. ThermodynamicsThermodynamics
At long chain lengths, the chainAt long chain lengths, the chain
propagation reactionpropagation reaction
is characterized by the followingis characterized by the following
equilibrium expression:equilibrium expression:
+ M
kp
kdp
Pn
* *Pn+1
k
k M
p
dp c
=
−
−
≅+[ P ]
[ P ][M]
n 1
*
n
*
1
[ ]
39. ThermodynamicsThermodynamics
The standard-state enthalpy and entropyThe standard-state enthalpy and entropy
of polymerization are related to theof polymerization are related to the
standard-state monomer concentration,standard-state monomer concentration,
[M][M]oo (usually neat liquid or 1 M solution) as(usually neat liquid or 1 M solution) as
follows:follows:
∆ ∆ ∆G H T S RTo o
= − + ln
[ ]
[ ]
M
M
o
40. ThermodynamicsThermodynamics
At equilibrium,At equilibrium, ∆∆G = 0, and T = TG = 0, and T = Tcc
(assuming that(assuming that ∆∆HHpp
oo
andand ∆∆SSpp
oo
areare
independent of temperature).independent of temperature).
Or:Or:
∆ ∆H T S RT
[M]
[M]
o
c
o
c
o
c
− = − ln
T
H
S Rln
[M]
[M]
c
o
o c
o
=
+
∆
∆
43. ThermodynamicsThermodynamics
Notice the large variation in the -Notice the large variation in the -∆∆HH
values.values.
ethylene > isobutylene - attributed to stericethylene > isobutylene - attributed to steric
hinderance along the polymer chain, which decreaseshinderance along the polymer chain, which decreases
the exothermicity of the polymerization reaction.the exothermicity of the polymerization reaction.
ethylene > styrene >ethylene > styrene > αα-metylstyrene - also due to-metylstyrene - also due to
increasing steric hinderance along the polymer chain.increasing steric hinderance along the polymer chain.
Note, however, that 2,4,6-trimethylstyrene has theNote, however, that 2,4,6-trimethylstyrene has the
same -same -∆∆H value as styrene. Clearly, the major effectH value as styrene. Clearly, the major effect
occurs for substituents directly attached to theoccurs for substituents directly attached to the
polymer backbone.polymer backbone.
44. Types of AdditionTypes of Addition
PolymerizationPolymerization
Free RadicalFree Radical
CationicCationic
AnionicAnionic
45. Free Radical PolymerizationFree Radical Polymerization
Usually, many low molecular weightUsually, many low molecular weight
alkenes undergo rapid polymerizationalkenes undergo rapid polymerization
reactions when treated with small amountsreactions when treated with small amounts
of a radical initiator.of a radical initiator.
For example, the polymerization ofFor example, the polymerization of
ethyleneethylene
50. Thermodynamic considerations forThermodynamic considerations for
the free radical polymerizationthe free radical polymerization
Chain growthChain growth
Activation energy for chain growth muchActivation energy for chain growth much
lower than for initiation.lower than for initiation.
i.e. Growth velocity less temperaturei.e. Growth velocity less temperature
dependent than initiationdependent than initiation
53. Macromonomer/ComonomerMacromonomer/Comonomer
Copolymerization Kinetics : free radicalCopolymerization Kinetics : free radical
In such copolymerizations, owing to the large differences in
molar mass between Macromonomer M and Comonomer A, the
monomer concentration is always very small : consequently the
classical instantaneous copolymerization equation
][]([r][
][][]([
][d
][d
M AMM
MArA
M
A a
+
+
=
Reduces to
][
][
][d
][d
M
Ar
M
A a
=
As in an « ideal » copolymerization the reciprocal of the radical reactivity
of the comonomer is a measure of the macromonomer to take part in the
process
Controlled Free Radical Copolymerization
54. Ionic PolymerizationIonic Polymerization
Ionic polymerization is more complex thanIonic polymerization is more complex than
free-radical polymerizationfree-radical polymerization
55. Ionic PolymerizationIonic Polymerization
Whereas free radical polymerization isWhereas free radical polymerization is
non-specific, the type of ionicnon-specific, the type of ionic
polymerization procedure and catalystspolymerization procedure and catalysts
depend on the nature of the substituentdepend on the nature of the substituent
(R) on the vinyl (ethenyl) monomer.(R) on the vinyl (ethenyl) monomer.
56. Ionic PolymerizationIonic Polymerization
Cationic initiation is therefore usuallyCationic initiation is therefore usually
limited to the polymerization of monomerslimited to the polymerization of monomers
where the R group is electron-donatingwhere the R group is electron-donating
This helps stabilise the delocation of theThis helps stabilise the delocation of the
positive charge through the p orbitals ofpositive charge through the p orbitals of
the double bondthe double bond
57. Ionic PolymerizationIonic Polymerization
Anionic initiation, requires the R group toAnionic initiation, requires the R group to
be electron withdrawing in order tobe electron withdrawing in order to
promote the formation of a stablepromote the formation of a stable
carbanion (ie, -M and -I effects helpcarbanion (ie, -M and -I effects help
stabilise the negative charge).stabilise the negative charge).
60. Ionic PolymerizationIonic Polymerization
M is a Monomer Unit.M is a Monomer Unit.
As these ions are associated with aAs these ions are associated with a
counter-ion or gegen-ion the solvent hascounter-ion or gegen-ion the solvent has
important effects on the polymerizationimportant effects on the polymerization
procedure.procedure.
61. Ionic PolymerizationIonic Polymerization
(ii) Chain Propagation depends on :(ii) Chain Propagation depends on :
Ion separationIon separation
The nature of the SolventThe nature of the Solvent
Nature of the counter IonNature of the counter Ion
62. Anionic PolymerizationAnionic Polymerization
Involves the polymerization of monomersInvolves the polymerization of monomers
that have strong electron-withdrawingthat have strong electron-withdrawing
groups, eg, acrylonitrile, vinyl chloride,groups, eg, acrylonitrile, vinyl chloride,
methyl methacrylate, styrene etc. Themethyl methacrylate, styrene etc. The
reactions can be initiated by methods (b)reactions can be initiated by methods (b)
and (c) as shown in the sheet on ionicand (c) as shown in the sheet on ionic
polymerizationpolymerization
64. Anionic PolymerizationAnionic Polymerization
The gegen-ion may be inorganic orThe gegen-ion may be inorganic or
organic and typical initiators includeorganic and typical initiators include
KNH2, n-BuLi, and Grignard reagentsKNH2, n-BuLi, and Grignard reagents
such as alkyl magnesium bromidessuch as alkyl magnesium bromides
65. Anionic PolymerizationAnionic Polymerization
If the monomer has only a weak electron-If the monomer has only a weak electron-
withdrawing group then a strong basewithdrawing group then a strong base
initiator is required, eg, butyllithium; forinitiator is required, eg, butyllithium; for
strong electron-withdrawing groups only astrong electron-withdrawing groups only a
weak base initiator is required, eg, aweak base initiator is required, eg, a
Grignard reagent.Grignard reagent.
66. Anionic PolymerizationAnionic Polymerization
Initiation mechanism (c) requires the directInitiation mechanism (c) requires the direct
transfer of an electron from the donor totransfer of an electron from the donor to
the monomer in order to form a radicalthe monomer in order to form a radical
anion.anion.
This can be achieved by using an alkaliThis can be achieved by using an alkali
metal eg.,metal eg.,
71. Anionic Polymerization of StyreneAnionic Polymerization of Styrene
The activation energy for transfer is larger than
for propagation, and so the chain length
decreases with increasing temperature.
72. Anionic KineticsAnionic Kinetics
A general description of the kinetics isA general description of the kinetics is
complicated however some usefulcomplicated however some useful
approximations may be attained.approximations may be attained.
73. Anionic KineticsAnionic Kinetics —— approximationsapproximations
1.1. The rate of polymerization will be proportionalThe rate of polymerization will be proportional
to the product of the monomer concentration ofto the product of the monomer concentration of
growing chain ends.growing chain ends.
2.2. Under conditions of negligible association eachUnder conditions of negligible association each
initiator molecule will start a growing chaininitiator molecule will start a growing chain
3.3. In the absence of terminating impurities theIn the absence of terminating impurities the
number of growing chain ends will always equalnumber of growing chain ends will always equal
the number of initiator molecules addedthe number of initiator molecules added
74. Anionic KineticsAnionic Kinetics
1.1. If propagation is rate controlingIf propagation is rate controling
(11-1)(11-1)[ ] [ ][ ]0IMk
dt
Md
r pp =
−
=
75. Anionic KineticsAnionic Kinetics
2.2. In BuLi polymerization at highIn BuLi polymerization at high
concentrations in non polar solvents, theconcentrations in non polar solvents, the
chain ends are present almostchain ends are present almost
exclusively as inactive dimmers, whichexclusively as inactive dimmers, which
dissociate slightly according to thedissociate slightly according to the
equilibriumequilibrium( ) +−+−
→← LiBuMLiBuM x
k
x 22
76. Anionic KineticsAnionic Kinetics
Where K=Where K=
3.3.The concentration of active chain ends isThe concentration of active chain ends is
thenthen
(11-3)(11-3)
Now it takes two initiator molecules toNow it takes two initiator molecules to
make one inactive chain dimmer, somake one inactive chain dimmer, so
(11-4)(11-4)
[ ] ( )[ ] 1/ 2
2
〈〈+−+−
LiBuMLiBuM xx
[ ] ( )[ ] 2/1
2
2
1
+−+−
= LiBuMKLiBuM xx
( )[ ] [ ] [ ]
22
0
2
IBuLi
LiBuM x ==+−
77. Anionic KineticsAnionic Kinetics
The rate of polymerisation then becomesThe rate of polymerisation then becomes
(11-5)(11-5)
The low value of K, reflecting the presence of most chainThe low value of K, reflecting the presence of most chain
ends in the inactive association state, gives rise to theends in the inactive association state, gives rise to the
low rates of polymerisation in nonpolar solvents. At verylow rates of polymerisation in nonpolar solvents. At very
high concentrations, association may be even greaterhigh concentrations, association may be even greater
and the rate essentially independent of [Iand the rate essentially independent of [I00]]
[ ] [ ] 2/1
02/1
2
=
−
=
I
Kk
dt
Md
r pp
79. Cationic PolymerizationCationic Polymerization
(ii) PropagationChain growth takes place(ii) PropagationChain growth takes place
through the repeated addition of athrough the repeated addition of a
monomer in a head-to-tail manner to themonomer in a head-to-tail manner to the
ion with retention of the ionic characterion with retention of the ionic character
throughoutthroughout
81. Cationic PolymerizationCationic Polymerization
(iii) Termination(iii) Termination
Termination of cationic polymerizationTermination of cationic polymerization
reactions are less well-defined than inreactions are less well-defined than in
free-radical processes. Two possibilitiesfree-radical processes. Two possibilities
exist as follows:exist as follows:
83. Cationic PolymerizationCationic Polymerization
Hydrogen abstraction occurs from theHydrogen abstraction occurs from the
growing chain to regenerate the catalyst-growing chain to regenerate the catalyst-
co-catalyst complex.co-catalyst complex.
Covalent combination of the active centreCovalent combination of the active centre
with a catalyst-co-catalyst complexwith a catalyst-co-catalyst complex
fragment may occur giving two inactivefragment may occur giving two inactive
species.species.
84. Cationic PolymerizationCationic Polymerization
The kinetic chain is terminated and theThe kinetic chain is terminated and the
initiator complex is reduced - a moreinitiator complex is reduced - a more
effective route to reaction termination.effective route to reaction termination.
86. Cationic PolymerizationCationic Polymerization
The kinetics of these reactions is not wellThe kinetics of these reactions is not well
understood, but they proceed very rapidlyunderstood, but they proceed very rapidly
at extremely low temperatures.at extremely low temperatures.
87. Polymerization Processes
TWO USEFUL DISTINCTIONS ;
BETWEEN BATCH AND CONTINUOUS
AND BETWEEN SINGLE - PHASE AND
MULTI -PHASE
SINGLE - PHASE
Bulk or Melt Polymerization
Solution Polymerization
89. Bulk PolymerizationBulk Polymerization
The simplest techniqueThe simplest technique
Gives the highest-purity polymerGives the highest-purity polymer
Only monomer, a monomer solubleOnly monomer, a monomer soluble
initiator and perhaps a chain transferinitiator and perhaps a chain transfer
agent are usedagent are used
This process can be used for many freeThis process can be used for many free
radical polymerizations and some step-radical polymerizations and some step-
growth (condensation) polymerisation.growth (condensation) polymerisation.
91. Bulk PolymerizationBulk Polymerization
Advantages:Advantages:
High yield per reactor volumeHigh yield per reactor volume
Easy polymer recoveryEasy polymer recovery
The option of casting the polymerisationThe option of casting the polymerisation
mixture into final product formmixture into final product form
92. Bulk PolymerizationBulk Polymerization
Limitations:Limitations:
Difficulty in removing the last traces ofDifficulty in removing the last traces of
monomermonomer
The problem of dissipating heat producedThe problem of dissipating heat produced
during the polymerizationduring the polymerization
In practice, heat dissipated during bulkIn practice, heat dissipated during bulk
polymerization can be improved by providingpolymerization can be improved by providing
special bafflesspecial baffles
93. Solution PolymerizationSolution Polymerization
Definition:Definition: A polymerization process inA polymerization process in
which the monomers and thewhich the monomers and the
polymerization initiators are dissolved in apolymerization initiators are dissolved in a
nonmonomeric liquid solvent at thenonmonomeric liquid solvent at the
beginning of the polymerization reaction.beginning of the polymerization reaction.
The liquid is usually also a solvent for theThe liquid is usually also a solvent for the
resulting polymer or copolymer.resulting polymer or copolymer.
94. Solution PolymerizationSolution Polymerization
Heat removed during polymerization canHeat removed during polymerization can
be facilitated by conducting thebe facilitated by conducting the
polymerization in an organic solvent orpolymerization in an organic solvent or
waterwater
95. Solution PolymerizationSolution Polymerization
Solvent Requirements:Solvent Requirements:
Both the initiator and the monomer beBoth the initiator and the monomer be
soluble in itsoluble in it
The solvent have acceptable chainThe solvent have acceptable chain
transfer characteristics and suitabletransfer characteristics and suitable
melting and boiling points for themelting and boiling points for the
conditions of the polymerization andconditions of the polymerization and
subsequent solvent-removal step.subsequent solvent-removal step.
96. Solution PolymerizationSolution Polymerization
Solvent choice may be influenced by otherSolvent choice may be influenced by other
factors such as flash point, cost andfactors such as flash point, cost and
toxicitytoxicity
Reactors are usually stainless steel orReactors are usually stainless steel or
glass linedglass lined
98. Suspension PolymerizationSuspension Polymerization
Definition:Definition: A polymerization process inA polymerization process in
which the monomer, or mixture ofwhich the monomer, or mixture of
monomers, is dispersed by mechanicalmonomers, is dispersed by mechanical
agitation in a liquid phase, usually water,agitation in a liquid phase, usually water,
in which the monomer droplets arein which the monomer droplets are
polymerized while they are dispersed bypolymerized while they are dispersed by
continuous agitation. Used primarily forcontinuous agitation. Used primarily for
PVC polymerizationPVC polymerization
99. Suspension PolymerizationSuspension Polymerization
If the monomer is insoluble in water, bulkIf the monomer is insoluble in water, bulk
polymerization can be carried out inpolymerization can be carried out in
suspended droplets, i.e., monomer issuspended droplets, i.e., monomer is
mechanically dispersed.mechanically dispersed.
The water phase becomes the heatThe water phase becomes the heat
transfer medium.transfer medium.
100. Suspension PolymerizationSuspension Polymerization
So the heat transfer is very good. In thisSo the heat transfer is very good. In this
system, the monomer must be eithersystem, the monomer must be either
1) insoluble in water or1) insoluble in water or
2) only slightly soluble in water, so that when2) only slightly soluble in water, so that when
it polymerizes it becomes insoluble in water.it polymerizes it becomes insoluble in water.
101. Suspension PolymerizationSuspension Polymerization
The behavior inside the droplets is veryThe behavior inside the droplets is very
much like the behavior of bulkmuch like the behavior of bulk
polymerizationpolymerization
Since the droplets are only 10 to 1000Since the droplets are only 10 to 1000
microns in diameter, more rapid reactionmicrons in diameter, more rapid reaction
rates can be tolerated (than would be therates can be tolerated (than would be the
case for bulk polymerization) withoutcase for bulk polymerization) without
boiling the monomer.boiling the monomer.
102. Emulsion PolymerizationEmulsion Polymerization
Emulsion polymerizationEmulsion polymerization is a type ofis a type of
radical polymerization that usually startsradical polymerization that usually starts
with an emulsion incorporating water,with an emulsion incorporating water,
monomer, and surfactant.monomer, and surfactant.
103. Emulsion PolymerizationEmulsion Polymerization
The most common type of emulsionThe most common type of emulsion
polymerization is an oil-in-water emulsion,polymerization is an oil-in-water emulsion,
in which droplets of monomer (the oil) arein which droplets of monomer (the oil) are
emulsified (with surfactants) in aemulsified (with surfactants) in a
continuous phase of water.continuous phase of water.
Water-soluble polymers, such as certainWater-soluble polymers, such as certain
polyvinyl alcohols or hydroxyethylpolyvinyl alcohols or hydroxyethyl
celluloses, can also be used to act ascelluloses, can also be used to act as
emulsifiers/stabilizers.emulsifiers/stabilizers.
105. Emulsion PolymerizationEmulsion Polymerization
Advantages of emulsion polymerization include:Advantages of emulsion polymerization include:
High molecular weight polymers can be made atHigh molecular weight polymers can be made at
fast polymerization rates. By contrast, in bulkfast polymerization rates. By contrast, in bulk
and solution free radical polymerization, there isand solution free radical polymerization, there is
a tradeoff between molecular weight anda tradeoff between molecular weight and
polymerization rate.polymerization rate.
The continuous water phase is an excellentThe continuous water phase is an excellent
conductor of heat and allows the heat to beconductor of heat and allows the heat to be
removed from the system, allowing manyremoved from the system, allowing many
reaction methods to increase their rate.reaction methods to increase their rate.
106. Emulsion PolymerizationEmulsion Polymerization
Advantages Continued:Advantages Continued:
Since polymer molecules are containedSince polymer molecules are contained
within the particles, viscosity remainswithin the particles, viscosity remains
close to that of water and is not dependentclose to that of water and is not dependent
on molecular weight.on molecular weight.
The final product can be used as is andThe final product can be used as is and
does not generally need to be altered ordoes not generally need to be altered or
processed.processed.
107. Emulsion PolymerizationEmulsion Polymerization
Disadvantages of emulsion polymerization include:Disadvantages of emulsion polymerization include:
For dry (isolated) polymers, water removal is anFor dry (isolated) polymers, water removal is an
energy-intensive processenergy-intensive process
Emulsion polymerizations are usually designedEmulsion polymerizations are usually designed
to operate at high conversion of monomer toto operate at high conversion of monomer to
polymer. This can result in significant chainpolymer. This can result in significant chain
transfer to polymer.transfer to polymer.
113. ExampleExample
Suggest a polymer and fabrication
process suitable to produce the following
items. Support your choice by contrasting
it with other possible alternatives.
Car bumper
Carry bag
Machine gear
Shower curtain
Tooth brush stand
114. SolutionSolution
i) Car bumper
Polyurethane is one of the suitable materials for car
bumpers. another suitable material is PP. Reaction
injection molding process is suitable to produce
polyurethane bumpers. Polyurethane is molded by
mixing of highly reactive liquids (isocyanateandpolyol).
Because the materials are very reactive liquids, Other
molding processes such as injection molding and
compression molding can not be used for this purpose.
However, injection molding and compression molding
methods can be used to make PP bumpers.
115. SolutionSolution
ii) Carry bag
Polyethylene (PE)is used widely for making
carry bags. Blown film extrusion methodis best
suitable to produce carry bags. Calendering
method also can be applied for the same
purpose. However, considering the production
rate and thickness range that can be produced,
blown film extrusion method is ideal to produce
carry bags.
Editor's Notes
Polymer- can have various lengths depending on number of repeat units
Relatively few polymers responsible for virtually all polymers sold – these are the bulk or commodity polymers