Effect of polymer structural factors on the mechanical properties
•Download as PPTX, PDF•
2 likes•1,339 views
This document discusses how various structural factors affect the mechanical properties of polymers. It examines the effects of molecular weight, cross-linking, crystallinity, polarity, copolymerization, and steric factors. Higher molecular weight, cross-linking density, crystallinity, and polarity generally increase the glass transition temperature and modulus. Crystallinity has a more pronounced effect above the glass transition temperature. Copolymerization can result in properties between the homopolymers or phase separation depending on the type of copolymer. Long flexible side chains decrease properties while branched side chains increase them.
Report
Share
Report
Share
Recommended
Crystallization and crystallinity of polymers
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.
Polymer properties and characterisation
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.
Crystallinity in polymers
The document discusses crystallinity in polymers. It defines crystalline and amorphous regions in polymers, and explains that polymers exist as a mixture of crystalline and amorphous phases. It describes how polymer chains fold and organize into crystalline lamellae and spherulites. The degree of crystallinity affects various material properties, and can be measured using techniques like DSC and X-ray diffraction. A higher crystallinity leads to properties like increased hardness, strength and barrier properties.
Glass transition temperature (tg)
Brief intro about crystalline and amorphous structures,
glass transition temperature,
free volume theory of glass transition temperature,
factors effecting glass transition temperature etc.
Polymer Additives and Blends
This document discusses fundamentals of polymer engineering, specifically polymer additives and blends. It defines additives as any substance added in small amounts to polymers to improve properties, facilitate processing, or reduce costs. Common additives include stabilizers, lubricants, fillers, plasticizers, and flame retardants. Fillers extend materials at low cost and can improve mechanical properties when well-dispersed. Polymer blends combine two or more polymers and offer benefits like extended temperature ranges, lighter weight, and improved toughness or barrier properties compared to the individual polymers. The classifications, functions, and examples of additives and blends in various polymer applications are covered in detail.
Miscibility and Thermodynamics of Polymer Blends
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
UNIT 2 Polymer Blends and Alloys.pptx
This document discusses polymer blends and alloys. It defines a polymer blend as a mixture of two or more polymers blended to create a new material with different physical properties. There are five main types of polymer blends that are categorized based on miscibility and methods of preparation such as mechanical, solution casting, and latex blends. Polymer blends can improve material properties such as cost, temperature range, toughness, and processability. They are classified as either miscible or immiscible based on whether a single or multiple glass transition temperatures are observed. Compatibilizers and graft copolymerization can be used to improve adhesion between immiscible polymer phases in a blend.
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...
additives of plastic.
uses of filler in plastic.
types of a heat stabilizer.
types of lubricant.
types of plasticizer in plastic.
plastic in antioxidant.
Recommended
Crystallization and crystallinity of polymers
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.
Polymer properties and characterisation
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.
Crystallinity in polymers
The document discusses crystallinity in polymers. It defines crystalline and amorphous regions in polymers, and explains that polymers exist as a mixture of crystalline and amorphous phases. It describes how polymer chains fold and organize into crystalline lamellae and spherulites. The degree of crystallinity affects various material properties, and can be measured using techniques like DSC and X-ray diffraction. A higher crystallinity leads to properties like increased hardness, strength and barrier properties.
Glass transition temperature (tg)
Brief intro about crystalline and amorphous structures,
glass transition temperature,
free volume theory of glass transition temperature,
factors effecting glass transition temperature etc.
Polymer Additives and Blends
This document discusses fundamentals of polymer engineering, specifically polymer additives and blends. It defines additives as any substance added in small amounts to polymers to improve properties, facilitate processing, or reduce costs. Common additives include stabilizers, lubricants, fillers, plasticizers, and flame retardants. Fillers extend materials at low cost and can improve mechanical properties when well-dispersed. Polymer blends combine two or more polymers and offer benefits like extended temperature ranges, lighter weight, and improved toughness or barrier properties compared to the individual polymers. The classifications, functions, and examples of additives and blends in various polymer applications are covered in detail.
Miscibility and Thermodynamics of Polymer Blends
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
UNIT 2 Polymer Blends and Alloys.pptx
This document discusses polymer blends and alloys. It defines a polymer blend as a mixture of two or more polymers blended to create a new material with different physical properties. There are five main types of polymer blends that are categorized based on miscibility and methods of preparation such as mechanical, solution casting, and latex blends. Polymer blends can improve material properties such as cost, temperature range, toughness, and processability. They are classified as either miscible or immiscible based on whether a single or multiple glass transition temperatures are observed. Compatibilizers and graft copolymerization can be used to improve adhesion between immiscible polymer phases in a blend.
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...
additives of plastic.
uses of filler in plastic.
types of a heat stabilizer.
types of lubricant.
types of plasticizer in plastic.
plastic in antioxidant.
Ppp8 2 Factors Affecting Tg
1. The document discusses the physical properties of polymers, specifically focusing on their glass transition temperature (Tg) and the factors that influence Tg.
2. Tg is affected by a polymer's chemical structure, molecular weight, addition of plasticizers, and whether it is a co-polymer. Flexible chains and side groups lower Tg, while increased polarity, crystallinity and bulky groups raise Tg.
3. Plasticizers reduce intermolecular forces and increase segmental motion, thereby decreasing Tg. Tg also increases with pressure and is generally correlated with, though separate from, a polymer's melting point.
Techniques of Polymerization
This document discusses various techniques of polymerization including bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and gas phase polymerization. It provides details on the process, advantages, disadvantages, and applications of each technique. The key techniques discussed are bulk, suspension, emulsion and gas phase polymerization which are widely used for industrial production of polymers.
Glass transition tempreature
A polymer is a large molecule, or macromolecule, composed of many
repeated subunits. The structure of a polymer is defined in terms of
crystallinity. This might also be thought of as the degree of order or regularity
in how the molecules are packed together. A well-ordered polymer is
considered crystalline. The opposite is an amorphous polymer. Almost
all amorphous polymers possess a temperature boundary. Above this
temperature the substance remains soft, rubbery and flexible, and below
this temperature it becomes hard, glassy and brittle.
The temperature, below which a polymer is hard and above which
it is soft is called the glass transition temperature.
For example:-
When an ordinary natural rubber ball if cooled below -70oC becomes so
hard and brittle that it will break into several pieces like a glass ball falling on a
hard surface.
This happens because there is a temperature boundary for amorphous.
The transition from the rubber to the glass-like state is an important feature of
polymer behavior, marking as it does a region where dramatic changes in the
physical properties, such as hardness and elasticity, are observed.
The hard, glassy, brittle state is known as the glassy state and the soft,
rubbery, flexible state is the rubbery or viscoelastic state. The glass transition
temperature is denoted by Tg.
Tf is another term for temperature, when a polymer is heated further, it forms
a viscous liquid and starts flowing, this state is known as viscous-fluid state
and the temperature is termed as flow temperature (Tf).
Tg is an important characteristic property of any polymer as it has an
important bearing on the potential application of a polymer.
Structure property relationship in polymer
This document discusses the relationship between polymer structure and properties such as solubility, glass transition temperature, thermal stability, and tensile strength. It explains that solubility decreases with longer branches or crosslinking. Glass transition temperature decreases with increased chain flexibility or bulky side groups but increases with crosslinking. Thermal stability is highest in polymers with aromatic or fluorine groups. Tensile strength follows the order branched < linear < crosslinked.
Glass transition temperature
The document discusses the glass transition temperature (Tg) of polymers. Tg is the temperature at which an amorphous polymer transitions from a brittle, glassy state to a rubbery, flexible state. It depends on factors like the polymer's chemical structure, molecular weight, and presence of plasticizers. Knowing the Tg is important as it indicates the physical state of the polymer and suitable processing conditions. It also provides information about the polymer's flexibility and how it will respond to mechanical stresses.
Dynamic mechanical analysis (DMA)
Dynamic Mechanical Analysis (DMA) is a technique that is widely used to characterize a material’s properties as a function of temperature, time, frequency, stress, atmosphere or a combination of these parameters.
Introduction to Polymer composites
This document provides an introduction to polymer composites. It defines composites as materials made of two or more chemically and physically distinct phases separated by a distinct interface. Composites combine materials to achieve properties not attainable by the individual components alone. The matrix phase holds the dispersed reinforcing phase and shares the applied load. Polymer composites offer advantages like high strength and stiffness, as well as good impact and corrosion resistance. Properties depend on factors like interfacial adhesion between phases, shape and orientation of the dispersed phase, matrix properties, and size and concentration of the dispersed phase. Processing methods for polymer composites include hand lay-up, injection molding, and pultrusion. Dental composites contain resin
Polymer nanocomposites, nanofillers and their applications
This content describes the different methods of fabrication and application of polymer nanocomposites
Polymers
- 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.
CHAPTER 5 behavior of polymers XX.ppt
This document discusses the properties of polymers. It begins by introducing the topics that will be covered, including physical, thermal, electrical, mechanical, thermo-mechanical, and chemical properties of polymers. It then provides details on various physical properties such as molecular weight and density. Thermal properties like glass transition temperature and melting point are explained. Factors that influence properties like mechanical strength and electrical conductivity of polymers are also described. The document aims to explain the different types of properties exhibited by polymers and factors that impact these properties.
Processing polymer
This document discusses various polymer processing techniques. It begins by outlining three general phases of plastics processes: heating, shaping/forming under constraint, and cooling. It then describes specific processes like thermoforming, compression and transfer molding, rotational molding, extrusion and extrusion-based processes, injection molding, and blow molding. For each process, it provides details on how it works, its advantages and disadvantages, and common applications.
Presentation dynamic mechanical analysis (dma)
Intro
Principle
How it works
Types of dynamic Experiments
Instrumentation
Construction
Preparation of samples
Types of analysers
DMA of glass transition of polymers
Advantages
Applications
Limitations
Latest Research
References
Polymers and its Viscoelastic Nature
This document discusses polymers and their viscoelastic properties. It begins with definitions of monomers, oligomers, and polymers. It then covers various classifications of polymers based on origin, monomer composition, chain structure, polymerization type, and applications. Fabrication methods like compression molding and injection molding are also presented. The document discusses characterization techniques including SEM, DSC, and tensile testing. Mechanical behavior concepts like stress relaxation and creep are introduced. Models for viscoelasticity such as the Maxwell and Kelvin-Voigt models are covered. The document ends with the latest research on self-healing polymers and conductive polymers.
POLYIMIDES
Polyimides are strong, heat and chemically resistant polymers formed from acid dianhydrides and diamines. They have applications as coatings, insulators, and mechanical parts due to their strength and durability. Polyimides are synthesized through a two-step polyaddition and dehydration reaction of acid anhydrides and diamines. They can replace metals and glass in applications due to their high heat resistance, strength, and transparency to microwaves.
Introduction to Polymers
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.
Lecture: Polymer Processing
The document discusses various plastic manufacturing processes including compression molding, transfer molding, injection molding, extrusion molding, blow molding, calendaring, thermoforming, and polymer foaming. It provides details on each process such as how it works, advantages, disadvantages, and applications. Key plastic types are also discussed including thermoplastics, thermosets, and different polymer foams.
Polymerization techniques
This PPT is related to the techniques utilized for polymerization process.
It can be useful to understand the basic concept of polymerization.
Calendering
A calender is a machine that processes polymer melts into sheets or films using heat and pressure between rollers. It works by softening the polymer and passing it through nips between two or more rollers to form a continuous sheet, with the thickness determined by the gap between the last rollers. Common uses of calendered sheets include flooring, rainwear, wall coverings, and signage. Thermoplastics are well-suited for calendering as they can soften without fully melting. Different roller configurations like I, L, and Z types address issues like separating forces between rollers. Calendering is advantageous for heat-sensitive materials but high capital costs and achieving precise thickness can be challenges
Addition polymerization, its examples and uses
Addition polymerization involves monomers joining together through a chain reaction without producing any byproducts. Common addition polymers include polyethylene, polyvinyl chloride, polyisoprene, polypropylene, and polystyrene. Addition polymerization can occur through bulk or solution polymerization. Bulk polymerization uses only the monomers while solution polymerization uses a solvent. Both methods have advantages like control over molecular weight but also disadvantages like poor heat transfer during bulk polymerization.
Crystallisability in polymer
This document discusses crystallinity and factors that affect crystallizability in polymers. It defines crystalline and amorphous solids, and explains that polymers exist as both crystalline and amorphous regions. Crystallinity refers to the amount of crystalline regions relative to amorphous regions. Crystallizability is the maximum crystallinity achievable at a given temperature. Factors that affect crystallizability include the polymer's molecular structure, molecular weight, branching, cis/trans configuration, homo- or co-polymer composition, polarity, and presence of bulky side groups. Homopolymers with linear and alternating structures tend to be more crystalline, while randomness, branching, and bulky groups inhibit crystallization.
Keshob's ppt
this ppt contain physical, mechanical and chemical properties of the polymer compound and their mechanical weight distribution. this ppt make an idea about all of the mentioned agenda.
MATERIALS TECHNOLOGY
This document provides an overview of materials technology and mechanical properties. It discusses how metals, plastics, and ceramics have different properties requiring different production technologies. Key mechanical properties like stress, strain, elasticity, strength, and toughness are defined. The document also summarizes different types of material deformation including elastic, plastic, viscoelastic, and superplastic deformation. Different strengthening mechanisms are described such as work hardening, solid solutioning, and dispersion hardening.
More Related Content
What's hot
Ppp8 2 Factors Affecting Tg
1. The document discusses the physical properties of polymers, specifically focusing on their glass transition temperature (Tg) and the factors that influence Tg.
2. Tg is affected by a polymer's chemical structure, molecular weight, addition of plasticizers, and whether it is a co-polymer. Flexible chains and side groups lower Tg, while increased polarity, crystallinity and bulky groups raise Tg.
3. Plasticizers reduce intermolecular forces and increase segmental motion, thereby decreasing Tg. Tg also increases with pressure and is generally correlated with, though separate from, a polymer's melting point.
Techniques of Polymerization
This document discusses various techniques of polymerization including bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and gas phase polymerization. It provides details on the process, advantages, disadvantages, and applications of each technique. The key techniques discussed are bulk, suspension, emulsion and gas phase polymerization which are widely used for industrial production of polymers.
Glass transition tempreature
A polymer is a large molecule, or macromolecule, composed of many
repeated subunits. The structure of a polymer is defined in terms of
crystallinity. This might also be thought of as the degree of order or regularity
in how the molecules are packed together. A well-ordered polymer is
considered crystalline. The opposite is an amorphous polymer. Almost
all amorphous polymers possess a temperature boundary. Above this
temperature the substance remains soft, rubbery and flexible, and below
this temperature it becomes hard, glassy and brittle.
The temperature, below which a polymer is hard and above which
it is soft is called the glass transition temperature.
For example:-
When an ordinary natural rubber ball if cooled below -70oC becomes so
hard and brittle that it will break into several pieces like a glass ball falling on a
hard surface.
This happens because there is a temperature boundary for amorphous.
The transition from the rubber to the glass-like state is an important feature of
polymer behavior, marking as it does a region where dramatic changes in the
physical properties, such as hardness and elasticity, are observed.
The hard, glassy, brittle state is known as the glassy state and the soft,
rubbery, flexible state is the rubbery or viscoelastic state. The glass transition
temperature is denoted by Tg.
Tf is another term for temperature, when a polymer is heated further, it forms
a viscous liquid and starts flowing, this state is known as viscous-fluid state
and the temperature is termed as flow temperature (Tf).
Tg is an important characteristic property of any polymer as it has an
important bearing on the potential application of a polymer.
Structure property relationship in polymer
This document discusses the relationship between polymer structure and properties such as solubility, glass transition temperature, thermal stability, and tensile strength. It explains that solubility decreases with longer branches or crosslinking. Glass transition temperature decreases with increased chain flexibility or bulky side groups but increases with crosslinking. Thermal stability is highest in polymers with aromatic or fluorine groups. Tensile strength follows the order branched < linear < crosslinked.
Glass transition temperature
The document discusses the glass transition temperature (Tg) of polymers. Tg is the temperature at which an amorphous polymer transitions from a brittle, glassy state to a rubbery, flexible state. It depends on factors like the polymer's chemical structure, molecular weight, and presence of plasticizers. Knowing the Tg is important as it indicates the physical state of the polymer and suitable processing conditions. It also provides information about the polymer's flexibility and how it will respond to mechanical stresses.
Dynamic mechanical analysis (DMA)
Dynamic Mechanical Analysis (DMA) is a technique that is widely used to characterize a material’s properties as a function of temperature, time, frequency, stress, atmosphere or a combination of these parameters.
Introduction to Polymer composites
This document provides an introduction to polymer composites. It defines composites as materials made of two or more chemically and physically distinct phases separated by a distinct interface. Composites combine materials to achieve properties not attainable by the individual components alone. The matrix phase holds the dispersed reinforcing phase and shares the applied load. Polymer composites offer advantages like high strength and stiffness, as well as good impact and corrosion resistance. Properties depend on factors like interfacial adhesion between phases, shape and orientation of the dispersed phase, matrix properties, and size and concentration of the dispersed phase. Processing methods for polymer composites include hand lay-up, injection molding, and pultrusion. Dental composites contain resin
Polymer nanocomposites, nanofillers and their applications
This content describes the different methods of fabrication and application of polymer nanocomposites
Polymers
- 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.
CHAPTER 5 behavior of polymers XX.ppt
This document discusses the properties of polymers. It begins by introducing the topics that will be covered, including physical, thermal, electrical, mechanical, thermo-mechanical, and chemical properties of polymers. It then provides details on various physical properties such as molecular weight and density. Thermal properties like glass transition temperature and melting point are explained. Factors that influence properties like mechanical strength and electrical conductivity of polymers are also described. The document aims to explain the different types of properties exhibited by polymers and factors that impact these properties.
Processing polymer
This document discusses various polymer processing techniques. It begins by outlining three general phases of plastics processes: heating, shaping/forming under constraint, and cooling. It then describes specific processes like thermoforming, compression and transfer molding, rotational molding, extrusion and extrusion-based processes, injection molding, and blow molding. For each process, it provides details on how it works, its advantages and disadvantages, and common applications.
Presentation dynamic mechanical analysis (dma)
Intro
Principle
How it works
Types of dynamic Experiments
Instrumentation
Construction
Preparation of samples
Types of analysers
DMA of glass transition of polymers
Advantages
Applications
Limitations
Latest Research
References
Polymers and its Viscoelastic Nature
This document discusses polymers and their viscoelastic properties. It begins with definitions of monomers, oligomers, and polymers. It then covers various classifications of polymers based on origin, monomer composition, chain structure, polymerization type, and applications. Fabrication methods like compression molding and injection molding are also presented. The document discusses characterization techniques including SEM, DSC, and tensile testing. Mechanical behavior concepts like stress relaxation and creep are introduced. Models for viscoelasticity such as the Maxwell and Kelvin-Voigt models are covered. The document ends with the latest research on self-healing polymers and conductive polymers.
POLYIMIDES
Polyimides are strong, heat and chemically resistant polymers formed from acid dianhydrides and diamines. They have applications as coatings, insulators, and mechanical parts due to their strength and durability. Polyimides are synthesized through a two-step polyaddition and dehydration reaction of acid anhydrides and diamines. They can replace metals and glass in applications due to their high heat resistance, strength, and transparency to microwaves.
Introduction to Polymers
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.
Lecture: Polymer Processing
The document discusses various plastic manufacturing processes including compression molding, transfer molding, injection molding, extrusion molding, blow molding, calendaring, thermoforming, and polymer foaming. It provides details on each process such as how it works, advantages, disadvantages, and applications. Key plastic types are also discussed including thermoplastics, thermosets, and different polymer foams.
Polymerization techniques
This PPT is related to the techniques utilized for polymerization process.
It can be useful to understand the basic concept of polymerization.
Calendering
A calender is a machine that processes polymer melts into sheets or films using heat and pressure between rollers. It works by softening the polymer and passing it through nips between two or more rollers to form a continuous sheet, with the thickness determined by the gap between the last rollers. Common uses of calendered sheets include flooring, rainwear, wall coverings, and signage. Thermoplastics are well-suited for calendering as they can soften without fully melting. Different roller configurations like I, L, and Z types address issues like separating forces between rollers. Calendering is advantageous for heat-sensitive materials but high capital costs and achieving precise thickness can be challenges
Addition polymerization, its examples and uses
Addition polymerization involves monomers joining together through a chain reaction without producing any byproducts. Common addition polymers include polyethylene, polyvinyl chloride, polyisoprene, polypropylene, and polystyrene. Addition polymerization can occur through bulk or solution polymerization. Bulk polymerization uses only the monomers while solution polymerization uses a solvent. Both methods have advantages like control over molecular weight but also disadvantages like poor heat transfer during bulk polymerization.
Crystallisability in polymer
This document discusses crystallinity and factors that affect crystallizability in polymers. It defines crystalline and amorphous solids, and explains that polymers exist as both crystalline and amorphous regions. Crystallinity refers to the amount of crystalline regions relative to amorphous regions. Crystallizability is the maximum crystallinity achievable at a given temperature. Factors that affect crystallizability include the polymer's molecular structure, molecular weight, branching, cis/trans configuration, homo- or co-polymer composition, polarity, and presence of bulky side groups. Homopolymers with linear and alternating structures tend to be more crystalline, while randomness, branching, and bulky groups inhibit crystallization.
What's hot (20)
Polymer nanocomposites, nanofillers and their applications
Polymer nanocomposites, nanofillers and their applications
Similar to Effect of polymer structural factors on the mechanical properties
Keshob's ppt
this ppt contain physical, mechanical and chemical properties of the polymer compound and their mechanical weight distribution. this ppt make an idea about all of the mentioned agenda.
MATERIALS TECHNOLOGY
This document provides an overview of materials technology and mechanical properties. It discusses how metals, plastics, and ceramics have different properties requiring different production technologies. Key mechanical properties like stress, strain, elasticity, strength, and toughness are defined. The document also summarizes different types of material deformation including elastic, plastic, viscoelastic, and superplastic deformation. Different strengthening mechanisms are described such as work hardening, solid solutioning, and dispersion hardening.
Tg
This document discusses polymer crystallinity and glass transition temperature. It begins by explaining that most polymers are either amorphous or semi-crystalline, with crystalline polymers having a sharp melting point and amorphous polymers lacking one. The degree of crystallinity refers to the amount of crystalline material in a polymer sample, which can be measured using methods like density measurements. Factors like molecular weight, symmetry, and branching affect crystallinity. The glass transition temperature (Tg) is the temperature at which an amorphous polymer transitions from hard and brittle to soft and flexible. The Williams-Landel-Ferry equation describes the relationship between viscosity and temperature above Tg. Factors like chain flexibility, intermolecular forces
Lecture: Microstructures in polymers
Lecture notes on Structure and Properties of Engineering Polymers
Course Objectives:
The main objective is to introduce polymers as an engineering material and emphasize the basic concepts of their nature, production and properties. Polymers are introduced at three levels; namely, the molecular level, the micro level, and macro-level. Through knowledge of all three levels, student can understand and predict the properties of various polymers and their performance in different products. The course also aims at introducing the students to the principles of polymer processing techniques and considerations of design using engineering polymers.
Polymer structures
Polymers can be either crystalline, semicrystalline, or amorphous depending on their molecular structure and processing conditions. Crystallinity affects key properties - semicrystalline polymers are opaque and have a melting point range, while amorphous polymers are clear with no defined melting point. The degree of crystallinity influences mechanical properties, with stiffness and strength increasing with crystallinity but ductility decreasing. Processing can induce crystallinity through molecular orientation. While crystallinity boosts some properties, it also makes them directionally dependent.
4. Introduction to PMC (1).pptx
This document discusses polymer matrix composites (PMCs). It defines PMCs and describes the two main types of polymer matrices: thermosets and thermoplastics. Thermosets cure irreversibly while thermoplastics can be remelted and reshaped. Common thermoset matrices include epoxies and unsaturated polyesters, while common thermoplastics include nylons and polyethylenes. The document also discusses different types of fillers/reinforcements like fibers, flakes and particulates that are added to polymers to improve mechanical properties. Finally, it examines different bonding mechanisms at the interface between the filler and matrix like mechanical, chemical, electrostatic and interdiffusion bonding that influence the
Plasticizer class ppt
Plasticizers are substances added to polymers to make them softer and more flexible. They work by inserting themselves between polymer chains and reducing intermolecular forces and friction. This lowers the glass transition temperature of the polymer. Common plasticizers are esters such as phthalates, adipates, and trimellitates. They are added to things like plastics, cosmetics, and pharmaceutical films to modify properties.
Molecular Weight affecting the Glass Transition temperature of Polymer
This is note about on the factors affecting glass transition temperature.
by Molecular weight in detail
advanced materials-converted-1.pdf
The document discusses the functions and desired properties of matrices in composite materials. Matrices hold fibers together, protect them from the environment, distribute loads evenly between fibers, and improve properties like impact resistance. Desired matrix properties include low moisture absorption, shrinkage, and thermal expansion. The document also discusses polymer matrix composites, classifications of polymers, factors affecting composite properties, and manufacturing processes for composites with thermoplastic and thermosetting matrices.
Polymers
This document discusses key concepts related to polymers and their biomedical applications. It defines thermoplastics and thermosets, and lists some common biomedical uses of polymers like PMMA, UHMWPE, PET, and silicones. It also summarizes polymer synthesis methods, including addition and condensation polymerization. Finally, it covers structural properties of polymers like crystallinity and morphology, as well as models for polymer behavior like reptation theory.
Polymer
polymerization is a process of bonding monomer, or "single units" together through a variety of reaction mechanisms to form longer chains named Polymer.
Evaluation of polymer
1. The document evaluates various physical properties of polymers including molecular weight, molecular shape, stereoregularity, branching, end-to-end distance, crystallinity, glass transition temperature, and tensile strength.
2. Several techniques for characterizing polymers are described, such as osmometry, light scattering, viscometry, and gel permeation chromatography for determining molecular weight, as well as differential scanning calorimetry and thermogravimetric analysis for analyzing thermal properties.
3. The physical properties of polymers depend on factors like molecular weight, chain structure, crystallinity, and temperature, and understanding these properties is important for evaluating polymers for different applications.
Introductions Polymers .pdf
This document provides an overview of polymers and rubber. It defines key polymerization terms like monomer, polymer, degree of polymerization, and discusses different types of polymerization including addition, condensation, and copolymerization. Natural rubber is made of polyisoprene and has limitations like low strength and reactivity which are addressed by vulcanization through crosslinking with sulfur. Commercial rubbers like Buna-S are discussed which is a styrene-butadiene copolymer used to make tires and insulation due to its tough mechanical properties.
Glass transition temperature
This slide is about the Glass transition temperature. This term used in Polymer Science.
Glass Transition Temperature
Chemistry
Polymer Science
Composites.ppt
Composite materials are made from two or more constituent materials that remain separate within the finished structure. They combine the strength of a reinforcement material like fibers with the toughness of a matrix material like polymer or metal. Common reinforcements include fibers, particles, and sheets, while matrix materials include polymer, metal, and ceramic. The arrangement and properties of the reinforcement and matrix provide composites with high strength, stiffness, corrosion resistance, and other desirable properties for applications in structures, aircraft, and vehicles.
Composites in Aviation.ppt
Composite make them best contenders to be used in aviation industry. Composites have revolutionized the aircraft industry through their properties especially regarding their strength & light in weight nature.
Composites.ppt
Composite materials are made from two or more constituent materials that remain separate within the finished structure. They combine the strength of the reinforcement material with the toughness of the matrix material. Common reinforcement materials are fibers, particles, or sheets that are embedded in a matrix such as polymer, metal, or ceramic. The properties of the composite depend on the types and amounts of reinforcement and matrix used. Composites are used in many applications that require high strength and stiffness combined with low weight, such as buildings, bridges, boats, and aircraft.
The Fundamentals of Rheology
This document discusses the fundamentals of rheology and how rheological tests can help with polymer processing and development. It describes different types of rheometers including capillary, rotational, and extensional rheometers. Capillary rheology provides information about how materials behave when melted and correlates flow parameters to mechanical properties. Capillary rheology can determine optimal processing parameters and investigate issues. The document also discusses how rheological properties relate to molecular weight and processing techniques like extrusion, injection molding, and blow molding that can be simulated using a capillary rheometer.
Super hard coatings
Recent advances in superhard nanocomposite coatings were presented. Nanocomposite coatings can be designed using various methods like combining two nanocrystalline phases or embedding nanocrystalline phases in an amorphous matrix to improve hardness and toughness. Coatings are synthesized using methods like chemical vapor deposition or magnetron sputtering. Properties are evaluated through nanoindentation, scratch adhesion testing, and measuring fracture toughness. Designing coatings with optimal parameters can yield both high hardness and toughness for industrial applications.
Super hard coatings
Recent advances in superhard nanocomposite coatings were presented. Nanocomposite coatings can be designed using various methods like combining two nanocrystalline phases or embedding nanocrystalline phases in an amorphous matrix to improve hardness and toughness. Coatings are synthesized using methods like chemical vapor deposition or magnetron sputtering. Properties are evaluated through nanoindentation, scratch adhesion testing, and measuring fracture toughness. Designing coatings with optimized parameters can provide both high hardness and toughness making nanocomposite coatings suitable for industrial applications.
Similar to Effect of polymer structural factors on the mechanical properties (20)
Molecular Weight affecting the Glass Transition temperature of Polymer
Molecular Weight affecting the Glass Transition temperature of Polymer
More from Vishal K P
Latex carpet backing
Latex is often used as a backing for carpets to improve anchorage of the pile and provide anti-slip characteristics. There are three main methods for applying latex to carpet backs: the lick-roll method, knife-over blanket spreading, and spraying. The lick-roll method involves coating the back of the carpet with latex from a revolving lick roller as it is pulled through an assembly. Knife-over blanket spreading similarly applies latex but uses a spreader instead of a roller. Spraying involves a spray gun that reciprocates above the moving carpet to uniformly coat its back with latex.
Epoxy resin composites
Epoxy resins are thermosetting polymers containing at least two epoxide groups. They are prepared through the reaction of bisphenol A and epichlorohydrin to form bisphenol A diglycidyl ethers. Epoxy resins can be cured through reaction with amines, acids, or anhydrides, forming a cross-linked three dimensional network structure. Common applications include surface coatings, composites with fibers like carbon and glass, which provide high strength and stiffness with lighter weight than metals.
Poly vinyl carbazole
Poly(vinyl carbazole) is known as a photoconductive material whose electrical conductivity increases with light exposure. It has good heat and chemical resistance and softens at 150°C. The monomer vinyl carbazole is prepared through a reaction of carbazole with acetylene and polymerized using initiators like di-tert-butyl peroxide. Poly(vinyl carbazole) is insoluble in many solvents and difficult to process, requiring high temperatures of 300°C for injection molding. Its main application is in electrostatic dry copying machines where it is used as the photoconductive layer in xerography.
Dyes for fibers
This document discusses different types of dyes. It begins with an introduction to dyes, noting that they are colored substances that bond to substrates and are often water-soluble. It then covers the main types of dyes including reactive dyes, which form covalent bonds; disperse dyes, which are used for synthetic fibers; azo dyes containing the R-N=N-R' group; sulfur dyes for cotton; and vat dyes which are insoluble but become soluble during the dyeing process. The document provides details on the characteristics and applications of each dye type.
Calibration systems for extruded pipes
This document discusses calibration systems used for extruded plastic tubes. There are two main types of calibration systems - external and internal. External calibrators employ a water-cooled forming tube that the extrudate slides against to harden, while internal calibrators use a tapered, water-cooled mandrel inside the tube. A combination system can provide smooth surfaces both inside and out. Proper sizing is important and factors like calibrator length, mandrel temperature, and vacuum assistance are considered to minimize defects during cooling and hardening of the extrudate.
Rubber footwears
This document provides information on the production of rubber footwear. It discusses the traditional hand assembly process and more modern direct moulding and injection moulding techniques. It describes the various materials used such as natural rubber, synthetic rubbers, fillers and chemicals. Specific compound formulations are provided for shoe uppers, soles and industrial boots. The production process involves preparing lasts, assembling parts, varnishing, and vulcanization. Compression moulding and injection moulding of soles and heels are also summarized.
Environmental issues related to polymer industries: Local and regional issues
Various local and regional impacts of polymer industries on the environment like acidification, littering, municipal solid wastes, smog, etc...
Electrospinning of nanofibers
The electrospinning technique of polymer nanofibers- Equipments, Factors affecting spinning, Applications.
Energy applications of polymer nanocomposites
Different applications of the polymer nanocomposites in energy applications such as batteries, capacitors, supercapacitors, etc..
More from Vishal K P (9)
Environmental issues related to polymer industries: Local and regional issues
Environmental issues related to polymer industries: Local and regional issues
Recently uploaded
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
The debris of the ‘last major merger’ is dynamically young
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
bordetella pertussis.................................ppt
Bordettela is a gram negative cocobacilli spread by air born drop let
3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
3D Particle-In-Cell (PIC) algorithm,
Plasma expansion in the dipole magnetic field.
Deep Software Variability and Frictionless Reproducibility
Deep Software Variability and Frictionless ReproducibilityUniversity of Rennes, INSA Rennes, Inria/IRISA, CNRS
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
SAR of Medicinal Chemistry 1st by dk.pdf
In this presentation include the prototype drug SAR on thus or with their examples .
Syllabus of Second Year B. Pharmacy
2019 PATTERN.
What is greenhouse gasses and how many gasses are there to affect the Earth.
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...
In this book, we use conservation of energy techniques on a fluid element to derive the Modified Bernoulli equation of flow with viscous or friction effects. We derive the general equation of flow/ velocity and then from this we derive the Pouiselle flow equation, the transition flow equation and the turbulent flow equation. In the situations where there are no viscous effects , the equation reduces to the Bernoulli equation. From experimental results, we are able to include other terms in the Bernoulli equation. We also look at cases where pressure gradients exist. We use the Modified Bernoulli equation to derive equations of flow rate for pipes of different cross sectional areas connected together. We also extend our techniques of energy conservation to a sphere falling in a viscous medium under the effect of gravity. We demonstrate Stokes equation of terminal velocity and turbulent flow equation. We look at a way of calculating the time taken for a body to fall in a viscous medium. We also look at the general equation of terminal velocity.
ESR spectroscopy in liquid food and beverages.pptx
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
BREEDING METHODS FOR DISEASE RESISTANCE.pptx
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
原版制作(carleton毕业证书)卡尔顿大学毕业证硕士文凭原版一模一样
原版纸张【微信：741003700 】【(carleton毕业证书)卡尔顿大学毕业证】【微信：741003700 】学位证，留信认证（真实可查，永久存档）offer、雅思、外壳等材料/诚信可靠,可直接看成品样本，帮您解决无法毕业带来的各种难题！外壳，原版制作，诚信可靠，可直接看成品样本。行业标杆！精益求精，诚心合作，真诚制作！多年品质 ,按需精细制作，24小时接单,全套进口原装设备。十五年致力于帮助留学生解决难题，包您满意。
本公司拥有海外各大学样板无数，能完美还原海外各大学 Bachelor Diploma degree, Master Degree Diploma
1:1完美还原海外各大学毕业材料上的工艺：水印，阴影底纹，钢印LOGO烫金烫银，LOGO烫金烫银复合重叠。文字图案浮雕、激光镭射、紫外荧光、温感、复印防伪等防伪工艺。材料咨询办理、认证咨询办理请加学历顾问Q/微741003700
留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
Orion Air Quality Monitoring Systems - CWS
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Leaf Initiation, Growth and Differentiation.pdf
Leaf initiation, growth and differentiation, genetic control of leaf development.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/Recently uploaded (20)
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...
The debris of the ‘last major merger’ is dynamically young
The debris of the ‘last major merger’ is dynamically young
bordetella pertussis.................................ppt
bordetella pertussis.................................ppt
3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
mô tả các thí nghiệm về đánh giá tác động dòng khí hóa sau đốt
mô tả các thí nghiệm về đánh giá tác động dòng khí hóa sau đốt
Deep Software Variability and Frictionless Reproducibility
Deep Software Variability and Frictionless Reproducibility
What is greenhouse gasses and how many gasses are there to affect the Earth.
What is greenhouse gasses and how many gasses are there to affect the Earth.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...
ESR spectroscopy in liquid food and beverages.pptx
ESR spectroscopy in liquid food and beverages.pptx
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
Effect of polymer structural factors on the mechanical properties
- 1. EFFECTS OF STRUCTURAL FACTORS ON MECHANICAL PROPERTIES Presented by, Vishal K.P. Dept. of PS&RT CUSAT
- 2. Introduction • When polymers are in to application , the mechanical properties should be analyzed for safety factors. • The properties includes strength, stiffness, ultimate tensile strength, modulus etc.. • Various structural factors also affect the mechanical properties of a polymer.
- 3. Structural Properties • Molecular weight • Cross-linking • Crystallinity • Polarity • Copolymerization • Steric factors
- 4. Effect of molecular weight • Tg-glassy to rubbery transition • Tfl-rubber to melt flow transition • The molecular weight has no effect on modulus in the glassy region(below Tg) • Tfl is dependant on molecular weight
- 5. Effect of Cross-linking • Smaller the value of Mc-a measure of cross- link density, higher the cross-link density. • Cross-links restricts the molecular mobility hence increases the ability to resist deformation under load i.e., increase modulus. • When cross-link density increases, restriction on molecular mobility increases and hence the Tg.
- 6. Effect of Crystallinity • Crystallinity-Molecules held together in an orderly manner by secondary valence bonds. • Crystallites have more modulii than amorphous segments • The effect on modulus below Tg is insignificant, but has a pronounced effect above the Tg. • The modulus will be high for polymers with higher percentage of crystallinity
- 7. Effect of crystallinity on the modulus-temperature curve
- 8. Effect of Polarity • The polarity increases the Tg of the polymers e.g.: Tg of polar PVC is 97°C higher than non- polar polypropylene • The modulus of polar polymer is much higher than non-polar polymers • Introduction of polar forces increases the modulus because the modulus in the glassy state is determined by the secondary bonding forces
- 9. Effect of copolymerization • Isomorphous systems *Homogeneous copolymers *The modulus will be in between that of two homopolymers • Non-Isomorphous system *random & alternating copolymers-same effect of isomorphous system *graft & block copolymers-two phases as dispersion >If dispersing medium is of high Tg,modulus will be higher. >If dispersing medium is of low Tg,modulus will be lower.
- 10. Effect of Steric factors • Long flexible side chains decreases the Tg and steric hinderance as a result of increasing free volume. • Branched side chains increases Tg and hence increases the modulus in the amorphous polymers.
- 11. Reference • POLYMER SCIENCE and TECHNOLOGY-Robert O.Ebewele: Chapman & Hall. Pg no.362-372
- 12. THANK YOU
Editor's Notes
- Viscous flow represents the complete mobility of the molecular chains. High M.W-high entanglements-high temperature needed to initiate mobility of chains.
- Mc-avg molecular weight between crosslinks
- Crystallinity-a form of physical cross-linking(thermoreverisble)
- The polarity increases modulus in only glassy region and not in rubbery region because after Tg the side chains starts movement and distance of polar groups increases frm main chain,which decreases the effect.