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.
all details about the chemistry of polymerization
Addition polymerization
Chemical Stages of polymerization
induction
propagation
chain transfer
termination
Inhibition of polymerization
Ring-opening polymerization,
Step growth/Condensation polymerization
Copolymerization
Acrylic resins
Methylmethacrylate
Polymethylmethacrylate{PMMA}
Multifunctional Methacrylate and Acrylate resins
All details about the dental polymer
Components and Composition
Molecular Weight
Polydispersity
Structure Of Polymer
Mechanical And Physical Properties Of Polymer,
Rheometric Properties
Solvation and dissolution Properties
Thermal Properties
Requirement Of Dental Resins
Dental Use Of Resins
This document discusses polymers and their use in dentistry. It begins with an introduction and overview of polymers and their increasing applications. It then covers the classification of polymers, including their thermal behavior as thermoplastics or thermosets. The document discusses the requisites and properties needed for dental resins, including biological compatibility, physical properties, and aesthetics. It covers the fundamental nature and chemistry of polymers, including polymerization, copolymerization, and the physical properties of polymers related to their structure and behavior with temperature changes.
This document defines dentures and their components. It discusses the different types of dentures - total versus partial. The main parts of a denture are the denture base and artificial teeth. Heat-cured polymethyl methacrylate (PMMA) is described as the most common denture base material. The setting process and requirements of denture base materials are outlined. Compression molding and injection molding techniques for constructing denture bases are also summarized.
This document provides an overview of different types of dental cements, including their composition, properties, and applications. It discusses zinc phosphate cement, the oldest cement still in use today. It also covers silicate cement, one of the first direct tooth-colored materials; zinc polycarboxylate cement, the first cement with adhesive properties; and zinc oxide eugenol cement, commonly used as a temporary cement. Modified versions of these traditional cements are also presented, along with other contemporary cements like glass ionomer cement and resin cements.
Glass-ionomer cement is used for various dental applications including final cementation, cavity bases, esthetic fillings, and orthodontic bracket cementation. It consists of a powder made of calcium-fluoro-alumino-silicate glass and a liquid containing polyacrylic acid. The acid-base setting reaction involves the glass dissolving in acid to release ions that crosslink the polyacrylic acid chains. Modifications include resin-modified glass-ionomer cement which incorporates resin monomers to form a protective matrix during the acid-base setting reaction.
Elastomeric impression materials include polysulfide, condensation silicone, addition silicone, and polyether rubbers. They set via polymerization reactions, with setting times of 8-12 minutes on average. Polysulfide and condensation silicone set via condensation reactions producing water or alcohol as byproducts, while addition silicone and polyether set via addition reactions without byproducts. Polysulfide has the highest detail reproduction but all materials exhibit some polymerization shrinkage. Materials are available in light, medium, heavy or putty consistencies for use with stock or custom trays. Proper manipulation is required for accurate impressions.
The document provides an overview of base metal alloys used in dentistry. It discusses the history and classification of dental casting alloys including cobalt-chromium, nickel-chromium, and titanium-based alloys. The ideal requirements, composition, properties, applications and references of various base metal alloys are described in detail over multiple pages.
all details about the chemistry of polymerization
Addition polymerization
Chemical Stages of polymerization
induction
propagation
chain transfer
termination
Inhibition of polymerization
Ring-opening polymerization,
Step growth/Condensation polymerization
Copolymerization
Acrylic resins
Methylmethacrylate
Polymethylmethacrylate{PMMA}
Multifunctional Methacrylate and Acrylate resins
All details about the dental polymer
Components and Composition
Molecular Weight
Polydispersity
Structure Of Polymer
Mechanical And Physical Properties Of Polymer,
Rheometric Properties
Solvation and dissolution Properties
Thermal Properties
Requirement Of Dental Resins
Dental Use Of Resins
This document discusses polymers and their use in dentistry. It begins with an introduction and overview of polymers and their increasing applications. It then covers the classification of polymers, including their thermal behavior as thermoplastics or thermosets. The document discusses the requisites and properties needed for dental resins, including biological compatibility, physical properties, and aesthetics. It covers the fundamental nature and chemistry of polymers, including polymerization, copolymerization, and the physical properties of polymers related to their structure and behavior with temperature changes.
This document defines dentures and their components. It discusses the different types of dentures - total versus partial. The main parts of a denture are the denture base and artificial teeth. Heat-cured polymethyl methacrylate (PMMA) is described as the most common denture base material. The setting process and requirements of denture base materials are outlined. Compression molding and injection molding techniques for constructing denture bases are also summarized.
This document provides an overview of different types of dental cements, including their composition, properties, and applications. It discusses zinc phosphate cement, the oldest cement still in use today. It also covers silicate cement, one of the first direct tooth-colored materials; zinc polycarboxylate cement, the first cement with adhesive properties; and zinc oxide eugenol cement, commonly used as a temporary cement. Modified versions of these traditional cements are also presented, along with other contemporary cements like glass ionomer cement and resin cements.
Glass-ionomer cement is used for various dental applications including final cementation, cavity bases, esthetic fillings, and orthodontic bracket cementation. It consists of a powder made of calcium-fluoro-alumino-silicate glass and a liquid containing polyacrylic acid. The acid-base setting reaction involves the glass dissolving in acid to release ions that crosslink the polyacrylic acid chains. Modifications include resin-modified glass-ionomer cement which incorporates resin monomers to form a protective matrix during the acid-base setting reaction.
Elastomeric impression materials include polysulfide, condensation silicone, addition silicone, and polyether rubbers. They set via polymerization reactions, with setting times of 8-12 minutes on average. Polysulfide and condensation silicone set via condensation reactions producing water or alcohol as byproducts, while addition silicone and polyether set via addition reactions without byproducts. Polysulfide has the highest detail reproduction but all materials exhibit some polymerization shrinkage. Materials are available in light, medium, heavy or putty consistencies for use with stock or custom trays. Proper manipulation is required for accurate impressions.
The document provides an overview of base metal alloys used in dentistry. It discusses the history and classification of dental casting alloys including cobalt-chromium, nickel-chromium, and titanium-based alloys. The ideal requirements, composition, properties, applications and references of various base metal alloys are described in detail over multiple pages.
The document provides a history of denture materials and techniques from ancient times to modern day. It begins with early dentures made of materials like wood, bone, ivory and human teeth. Important developments include the introduction of porcelain and vulcanite dentures in the 18th-19th centuries. In the 1930s, polymethyl methacrylate (PMMA) was introduced and became the standard denture material due to its strength, biocompatibility and ease of use. The document also describes the compression molding technique for fabricating PMMA dentures, involving steps like flasking, packing, curing and finishing. Alternative techniques like injection molding are also mentioned.
Dental casting alloys can be categorized as either noble metal alloys or base metal alloys. Noble metal alloys contain precious metals like gold, palladium, or silver and are commonly used to create indirect restorations through lost wax casting. Base metal alloys do not contain precious metals and provide a more economical option for removable partial denture frameworks and other restorations requiring high strength. Both alloy types aim to have suitable mechanical properties for their intended use as well as biocompatibility and corrosion resistance through alloying elements and microstructure design.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document discusses glass ionomer cements, including their definitions, composition, and scientific/clinical development. It defines glass ionomer cement as a cement consisting of a basic glass and an acidic polymer that sets via an acid-base reaction. The basic components are calcium fluoroaluminosilicate glasses containing fluoride. The acidic components are polyelectrolytes made of polymers of unsaturated carboxylic acids like poly(acrylic acid). The document traces the scientific development of glass ionomer cements from early experiments in the 1960s to modern resin-modified varieties.
Composite materials are made of a resin matrix and filler particles. They have superior properties to their individual components. There are several types of composites classified by filler particle size: macrofilled (8-12 μm), small particle (1-5 μm), microfilled (0.04-0.4 μm), and hybrid (1 μm). Macrofilled composites have the largest particles and produce the roughest surfaces, while microfilled composites have the smallest particles and smoothest surfaces. Hybrid composites have a mixture of particle sizes. The different types have various indications for use depending on their mechanical properties and ability to be polished.
This document provides an overview of various types of dental cements. It begins with definitions and a brief history of dental cements. It then classifies cements based on their ingredients and discusses their ideal requirements. The document goes on to describe specific cement types in detail, including their characteristics, properties, and uses. It covers traditional cements like zinc phosphate, as well as contemporary materials like resin-modified glass ionomers. The document provides a comprehensive reference on the formulation and application of different dental cements.
This document discusses casting alloys used in dentistry. It begins with a brief history of casting alloys and their evolution since the 1900s. It then covers the key properties casting alloys must have including biocompatibility, corrosion resistance, hardness, castability and bonding to ceramics. The document classifies casting alloys and discusses commonly used types such as gold alloys, silver-palladium alloys, cobalt-chrome alloys and titanium alloys. It provides details on the composition and characteristics of different alloy groups.
Denture base resins are typically made of polymethyl methacrylate (PMMA) and are fabricated using heat- or chemically- activated resins. PMMA denture bases are hard, transparent, and resistant to discoloration. The resins undergo polymerization shrinkage of around 21% as the monomer methyl methacrylate forms chains and evaporates slightly during processing. Proper mixing and compression molding can minimize porosity and achieve adequate polymerization for optimal denture fit and function.
Dental polymers with recent advancements in dental base techniques 2PoojaKhandelwal45
This document discusses recent advancements in dental polymers and base techniques. It begins with definitions of polymers and polymerization. The history of dental polymers is then reviewed, including the development of synthetic elastomers in the 20th century and the introduction of PMMA and resin-based composites. Various dental applications of polymers are listed. Key aspects of polymers like chain length, branching, copolymer structures, and properties are described. The document concludes with an overview of addition and step-growth polymerization, as well as details on acrylic dental resins.
Cobalt-chromium, nickel-chromium, and titanium alloys are commonly used as alternatives to gold alloys for dental casting. Cobalt-chromium alloys contain cobalt, chromium, and molybdenum as major elements, while nickel-chromium alloys contain nickel, chromium, and molybdenum. Titanium can be used in pure form or as alloys to stabilize its crystal structure. These base metal alloys have higher strength and modulus of elasticity than gold, but are less ductile. They provide excellent corrosion resistance due to the formation of a passive oxide layer on the surface. Casting of titanium and titanium alloys requires special techniques and equipment due to their high melting temperatures and low density
This document discusses dental composites, including their:
- History dating back to the 1940s and developments since then
- Composition of a matrix, fillers, and coupling agent
- Classification based on filler size, curing method, area of use, and generations
- Properties including strength, smoothness, and polymerization shrinkage
- Advantages such as esthetics and bond strength, as well as disadvantages like polymerization shrinkage.
INTRODUCTION
HISTORY
REQUISITES FOR IDEAL DENTURE BASE MATERIAL
CLASSIFICATION
METAL DENTURE BASE
DENTURE BASE POLYMERS
RECENT ADVANCES
CONCLUSION
REFERANCES
The document discusses heat cure acrylic denture base resins. It provides background on the development of denture base materials over time. Polymethyl methacrylate (PMMA) was introduced in 1937 and remains the material of choice due to its superior esthetics, ease of processing, accurate fit, and use with inexpensive equipment. The document describes the composition, chemical basis of polymerization, manipulation techniques including compression molding and injection molding, and physical properties of heat cure acrylic resins. It also compares heat cure resins to self-cure resins and discusses requirements versus clinical performance as well as recent advances in the material.
Physical and Mechanical Properties of CompositesHeatherSeghi
The document discusses various physical and mechanical properties of dental composites, including biocompatibility, strength, wear resistance, polymerization shrinkage, degree of conversion, thermal conductivity, coefficient of thermal expansion, elastic modulus, water sorption, and radiopacity. It describes how properties such as strength, wear, shrinkage, conversion and modulus are affected by the composite's filler content and composition. Strategies for reducing shrinkage like incremental layering and use of prepolymerized filler are also covered.
Calcium hydroxide cements were introduced by Hermann in 1920 as an alternative to viewing exposed pulps as "doomed organs." Calcium hydroxide cements promote healing in clinical situations by creating an alkaline environment. They are formed through a reaction of calcium oxide with water to create calcium hydroxide. Typical calcium hydroxide cements are composed of calcium hydroxide, zinc oxide, zinc stearate, and ethyl toluene sulphonamide. They set through exothermic chemical reactions, have biocompatibility that can destroy bacteria and initiate reparative dentin formation, but have low strength and solubility in moisture.
The document provides an overview of elastomeric impression materials. It begins with an introduction and definitions of key terms like elastomer and elastomeric impression materials. It then discusses the history and classifications of impression materials. The document outlines the ideal requirements for impression materials and their clinical applications. It describes the properties and composition of various elastomers like polysulfide, condensation silicone, addition silicone, and polyether. It discusses recent advances in impression materials and effects of mishandling impressions. In conclusion, the document provides a comprehensive review of elastomeric impression materials.
The document provides information on gold casting alloys used for dental restorations. It discusses the general requirements for these alloys, including physical, chemical, mechanical and biological properties. It also covers terminology related to precious metal alloys and common commercial examples. Processing cycles and potential casting problems are described, such as distortion, surface irregularities and incomplete castings due to factors like investment expansion/contraction, gas inclusions and improper spruing. Copyright and usage information is provided.
The document discusses dental casting alloys, including their history, desirable properties, composition, classification into noble metal alloys and base metal alloys. Key points covered include the importance of biocompatibility, corrosion resistance, aesthetics and thermal properties of alloys. Common metals used in alloys such as gold, palladium, silver and nickel are described.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The document provides a history of denture materials and techniques from ancient times to modern day. It begins with early dentures made of materials like wood, bone, ivory and human teeth. Important developments include the introduction of porcelain and vulcanite dentures in the 18th-19th centuries. In the 1930s, polymethyl methacrylate (PMMA) was introduced and became the standard denture material due to its strength, biocompatibility and ease of use. The document also describes the compression molding technique for fabricating PMMA dentures, involving steps like flasking, packing, curing and finishing. Alternative techniques like injection molding are also mentioned.
Dental casting alloys can be categorized as either noble metal alloys or base metal alloys. Noble metal alloys contain precious metals like gold, palladium, or silver and are commonly used to create indirect restorations through lost wax casting. Base metal alloys do not contain precious metals and provide a more economical option for removable partial denture frameworks and other restorations requiring high strength. Both alloy types aim to have suitable mechanical properties for their intended use as well as biocompatibility and corrosion resistance through alloying elements and microstructure design.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document discusses glass ionomer cements, including their definitions, composition, and scientific/clinical development. It defines glass ionomer cement as a cement consisting of a basic glass and an acidic polymer that sets via an acid-base reaction. The basic components are calcium fluoroaluminosilicate glasses containing fluoride. The acidic components are polyelectrolytes made of polymers of unsaturated carboxylic acids like poly(acrylic acid). The document traces the scientific development of glass ionomer cements from early experiments in the 1960s to modern resin-modified varieties.
Composite materials are made of a resin matrix and filler particles. They have superior properties to their individual components. There are several types of composites classified by filler particle size: macrofilled (8-12 μm), small particle (1-5 μm), microfilled (0.04-0.4 μm), and hybrid (1 μm). Macrofilled composites have the largest particles and produce the roughest surfaces, while microfilled composites have the smallest particles and smoothest surfaces. Hybrid composites have a mixture of particle sizes. The different types have various indications for use depending on their mechanical properties and ability to be polished.
This document provides an overview of various types of dental cements. It begins with definitions and a brief history of dental cements. It then classifies cements based on their ingredients and discusses their ideal requirements. The document goes on to describe specific cement types in detail, including their characteristics, properties, and uses. It covers traditional cements like zinc phosphate, as well as contemporary materials like resin-modified glass ionomers. The document provides a comprehensive reference on the formulation and application of different dental cements.
This document discusses casting alloys used in dentistry. It begins with a brief history of casting alloys and their evolution since the 1900s. It then covers the key properties casting alloys must have including biocompatibility, corrosion resistance, hardness, castability and bonding to ceramics. The document classifies casting alloys and discusses commonly used types such as gold alloys, silver-palladium alloys, cobalt-chrome alloys and titanium alloys. It provides details on the composition and characteristics of different alloy groups.
Denture base resins are typically made of polymethyl methacrylate (PMMA) and are fabricated using heat- or chemically- activated resins. PMMA denture bases are hard, transparent, and resistant to discoloration. The resins undergo polymerization shrinkage of around 21% as the monomer methyl methacrylate forms chains and evaporates slightly during processing. Proper mixing and compression molding can minimize porosity and achieve adequate polymerization for optimal denture fit and function.
Dental polymers with recent advancements in dental base techniques 2PoojaKhandelwal45
This document discusses recent advancements in dental polymers and base techniques. It begins with definitions of polymers and polymerization. The history of dental polymers is then reviewed, including the development of synthetic elastomers in the 20th century and the introduction of PMMA and resin-based composites. Various dental applications of polymers are listed. Key aspects of polymers like chain length, branching, copolymer structures, and properties are described. The document concludes with an overview of addition and step-growth polymerization, as well as details on acrylic dental resins.
Cobalt-chromium, nickel-chromium, and titanium alloys are commonly used as alternatives to gold alloys for dental casting. Cobalt-chromium alloys contain cobalt, chromium, and molybdenum as major elements, while nickel-chromium alloys contain nickel, chromium, and molybdenum. Titanium can be used in pure form or as alloys to stabilize its crystal structure. These base metal alloys have higher strength and modulus of elasticity than gold, but are less ductile. They provide excellent corrosion resistance due to the formation of a passive oxide layer on the surface. Casting of titanium and titanium alloys requires special techniques and equipment due to their high melting temperatures and low density
This document discusses dental composites, including their:
- History dating back to the 1940s and developments since then
- Composition of a matrix, fillers, and coupling agent
- Classification based on filler size, curing method, area of use, and generations
- Properties including strength, smoothness, and polymerization shrinkage
- Advantages such as esthetics and bond strength, as well as disadvantages like polymerization shrinkage.
INTRODUCTION
HISTORY
REQUISITES FOR IDEAL DENTURE BASE MATERIAL
CLASSIFICATION
METAL DENTURE BASE
DENTURE BASE POLYMERS
RECENT ADVANCES
CONCLUSION
REFERANCES
The document discusses heat cure acrylic denture base resins. It provides background on the development of denture base materials over time. Polymethyl methacrylate (PMMA) was introduced in 1937 and remains the material of choice due to its superior esthetics, ease of processing, accurate fit, and use with inexpensive equipment. The document describes the composition, chemical basis of polymerization, manipulation techniques including compression molding and injection molding, and physical properties of heat cure acrylic resins. It also compares heat cure resins to self-cure resins and discusses requirements versus clinical performance as well as recent advances in the material.
Physical and Mechanical Properties of CompositesHeatherSeghi
The document discusses various physical and mechanical properties of dental composites, including biocompatibility, strength, wear resistance, polymerization shrinkage, degree of conversion, thermal conductivity, coefficient of thermal expansion, elastic modulus, water sorption, and radiopacity. It describes how properties such as strength, wear, shrinkage, conversion and modulus are affected by the composite's filler content and composition. Strategies for reducing shrinkage like incremental layering and use of prepolymerized filler are also covered.
Calcium hydroxide cements were introduced by Hermann in 1920 as an alternative to viewing exposed pulps as "doomed organs." Calcium hydroxide cements promote healing in clinical situations by creating an alkaline environment. They are formed through a reaction of calcium oxide with water to create calcium hydroxide. Typical calcium hydroxide cements are composed of calcium hydroxide, zinc oxide, zinc stearate, and ethyl toluene sulphonamide. They set through exothermic chemical reactions, have biocompatibility that can destroy bacteria and initiate reparative dentin formation, but have low strength and solubility in moisture.
The document provides an overview of elastomeric impression materials. It begins with an introduction and definitions of key terms like elastomer and elastomeric impression materials. It then discusses the history and classifications of impression materials. The document outlines the ideal requirements for impression materials and their clinical applications. It describes the properties and composition of various elastomers like polysulfide, condensation silicone, addition silicone, and polyether. It discusses recent advances in impression materials and effects of mishandling impressions. In conclusion, the document provides a comprehensive review of elastomeric impression materials.
The document provides information on gold casting alloys used for dental restorations. It discusses the general requirements for these alloys, including physical, chemical, mechanical and biological properties. It also covers terminology related to precious metal alloys and common commercial examples. Processing cycles and potential casting problems are described, such as distortion, surface irregularities and incomplete castings due to factors like investment expansion/contraction, gas inclusions and improper spruing. Copyright and usage information is provided.
The document discusses dental casting alloys, including their history, desirable properties, composition, classification into noble metal alloys and base metal alloys. Key points covered include the importance of biocompatibility, corrosion resistance, aesthetics and thermal properties of alloys. Common metals used in alloys such as gold, palladium, silver and nickel are described.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
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.
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).
lect dental-polymers.ppt including heat and coldmanjulikatyagi
This document summarizes key information about dental polymers, including the types of resins used in dentistry, how they are classified, and the polymerization process. It discusses the main categories of polymers as thermoplastic and thermoset, and how polymerization occurs through addition and condensation reactions. The stages of polymerization - initiation, propagation and termination - are outlined. Factors that can inhibit polymerization and the physical properties of polymers related to deformation, rheology, solvation and thermal behavior are also summarized.
Macromolecules are large molecules formed by linking many smaller units, or monomers, through covalent bonds. Natural substances like proteins and synthetic polymers are examples of macromolecules. Monomers undergo polymerization to form macromolecules by linking together through addition or condensation reactions. Polymers can be classified in different ways such as natural vs synthetic, organic vs inorganic, thermoplastic vs thermosetting, and linear, branched or cross-linked based on their molecular structure. The process of polymerization and properties of polymers depend on factors like the type of monomers, reaction conditions and molecular architecture.
This document summarizes a seminar presentation on polymer science given to Dr. R. V. Kulkarni. The presentation covered various topics including polymer classification, applications of polymers in controlled drug delivery, biodegradable and natural polymers. Key points discussed include the different methods of polymer classification including by linking method, composition, polymerization method, mechanism and origin. Important polymerization methods like addition, condensation and step-growth were also summarized.
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.
This document summarizes different types of polymers. It discusses the classification of polymers based on source, structure, mode of polymerization, molecular forces, and provides examples. Key polymers discussed include polyethylene, polyvinyl chloride, nylon, bakelite, phenol-formaldehyde, and melamine-formaldehyde. The document also explains the processes of addition, condensation, and step-growth polymerization.
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.
The document discusses various topics related to polymers including their classification, types, mechanisms of polymerization, and polymerization reactions. It classifies polymers based on their chain structure, chemical composition, source, and backbone. The main types discussed are thermoplastics, thermosets, and elastomers. It describes the mechanisms of condensation and addition polymerization. Chain polymerization reactions like free radical, anionic and cationic polymerization are explained in detail with their initiation, propagation and termination steps.
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.
This document discusses polymers, including their classification, types, properties, and applications. Polymers are high molecular mass substances composed of repeating structural units joined by covalent bonds. They can be classified as homopolymers or copolymers depending on the number of monomer units. Polymers are also classified by their polymerization reaction as addition or condensation polymers. Examples of common polymers are discussed. The properties of polymers depend on factors like chain length and branching, which influence strength. Polymers have a wide range of applications, from packaging and clothing to industrial uses like pipes and tanks to sports equipment and medical uses like surgical materials.
This document provides an overview of polymer science. It begins with definitions, noting that a polymer is a large molecule formed by linking small repeating units called monomers. The document then covers various classifications of polymers based on their source, backbone, structure, and polymerization method. Applications of polymers in pharmaceutical formulations and drug delivery are discussed, along with mechanisms of drug release from polymers. The document also addresses viscosity, solvent selection, and common fabrication technologies for polymers.
This document summarizes various ways of classifying polymers. Polymers can be classified based on their structure as linear, branched, or cross-linked. They can also be classified based on their source as natural, semi-synthetic, or synthetic. Additionally, polymers are classified based on the number and arrangement of monomers, their configuration, the intermolecular forces between chains, and the type of polymerization reaction (addition or condensation). The document provides examples for most polymer classifications.
Polymers are giant molecules composed of repeating structural units joined together. They can be classified based on their origin (natural, semi-synthetic, synthetic), thermal response (thermoplastic, thermosetting), structure (linear, branched, cross-linked), and application (rubber, plastic, fibers). Polymerization is the process of linking monomers together to form polymers. It occurs via two main mechanisms: step-growth polymerization (condensation polymerization) and chain-growth polymerization (addition polymerization). Step-growth involves the elimination of a small molecule as monomers react together in a step-wise manner, while chain-growth is a chain reaction with no byproducts as monomers continuously add to the
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.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
1. Dental Bio-materialsDental Bio-materials
Ass. Prof. Dr. Mohamed Abed el-Aziz SouhailAss. Prof. Dr. Mohamed Abed el-Aziz Souhail
Head of Dental Bio-material Department,Head of Dental Bio-material Department,
Faculty of Dental Medicine,Faculty of Dental Medicine,
Al- Azhar University.Al- Azhar University.
2. POLYMERSPOLYMERS
Polymers are Plastic and rubbersPolymers are Plastic and rubbers
Polymers Are long chain molecules consistingPolymers Are long chain molecules consisting
of many (poly) repeating units (mers).of many (poly) repeating units (mers).
A monomer: Is the smallest repeating unit inA monomer: Is the smallest repeating unit in
the polymerthe polymer
PolymerizationPolymerization : Is the chemical reaction by: Is the chemical reaction by
which polymers are formed from monomerswhich polymers are formed from monomers
chain e.g. ethylene monomer.chain e.g. ethylene monomer.
4. The originThe origin
Natural polymersNatural polymers
Agar, celluloseAgar, cellulose
DNA, proteinsDNA, proteins
Natural rubberNatural rubber
Collagen and silkCollagen and silk
5. A) Synthetic PolymersA) Synthetic Polymers
ِِProduced in the laboratory by chemicalProduced in the laboratory by chemical
reactions. e.g. Acrylic resin ,nylon andreactions. e.g. Acrylic resin ,nylon and
polystyrene.polystyrene.
Originally the synthetic polymers regarded asOriginally the synthetic polymers regarded as
substitutes for existing natural polymers suchsubstitutes for existing natural polymers such
as rubber and silk .Nowadays a polymers canas rubber and silk .Nowadays a polymers can
be produced and have medical use such asbe produced and have medical use such as
dialysis and oxygenator membranes anddialysis and oxygenator membranes and
dental application such as filling materialsdental application such as filling materials ..
6. B) Natural PolymersB) Natural Polymers
Proteins polyamides of polypeptidesProteins polyamides of polypeptides
polyisoprenespolyisoprenes
e.g. rubber and gutta-perchae.g. rubber and gutta-percha
polysaccharidespolysaccharides
e.g. starch , cellulose, agar and alginate .e.g. starch , cellulose, agar and alginate .
poly nucleic acidspoly nucleic acids
such as DNA and RNA.such as DNA and RNA.
7. According To Thermal BehaviorAccording To Thermal Behavior
Thermoplastic resinThermoplastic resin
They are polymers which can beThey are polymers which can be
shaped by heat and after coolingshaped by heat and after cooling
they maintain their shape thethey maintain their shape the
reaction is reversible and can bereaction is reversible and can be
repeatedrepeated
8. characteristicscharacteristics
The polymer chains are bonded to each other by secondary bond.The polymer chains are bonded to each other by secondary bond.
They are relatively soft and their mechanical propertiesThey are relatively soft and their mechanical properties
are sensitive to heat.are sensitive to heat.
They dissolve in organic solvent thermosetting polymersThey dissolve in organic solvent thermosetting polymers
They are formed into a permanent shapeThey are formed into a permanent shape
and set by chemical reaction.and set by chemical reaction.
They can not be remelted and reformed into another shape butThey can not be remelted and reformed into another shape but
degrade or decompose up on being heated to high temperature..degrade or decompose up on being heated to high temperature..
Thermoset cannot be fused.Thermoset cannot be fused.
The polymers form network with cross –links between them primaryThe polymers form network with cross –links between them primary
covalent bonds. E.g. PMMA.covalent bonds. E.g. PMMA.
10. b) Thermoset polymersb) Thermoset polymers
Harden during fabrication (irreversible or chemicalHarden during fabrication (irreversible or chemical
reaction).reaction).
ChemicalChemical
Soft hardSoft hard
reactionreaction
Examples are cross-linkedExamples are cross-linked
polymethylmethacrylate, silicons ,and bisphenolpolymethylmethacrylate, silicons ,and bisphenol
A-diacrylates.A-diacrylates.
11. According to the basis of structural or spatialAccording to the basis of structural or spatial
configurationconfiguration
linea
r
copolymer
Simple polymer
Has one type
monomer
homopolymer
Branched
Random
Block
OR
Homo
Copolymer
OR
graftRandom
3 Basic Types
Cross-linked
polymer
12. ))a) Linear polymers
(simple polymer)
This may be homopolymerThis may be homopolymer it has one type ofit has one type of
monomer ,monomer ,or copolymer, this means thator copolymer, this means that it hasit has
more than one type of monomer,more than one type of monomer,
Homopolymer copolymer, randomHomopolymer copolymer, random
blockblock
13. b) Branched polymersb) Branched polymers
This type of polymers show higher strength hardness andThis type of polymers show higher strength hardness and
less water sorption than linear polymer .less water sorption than linear polymer .
Branched polymers are either homo or copolymer TheBranched polymers are either homo or copolymer The
branched copolymer may be random or graft types.branched copolymer may be random or graft types.
Homopolymer copolymer, randomHomopolymer copolymer, random
graftgraft
2
14. C) Cross-LinkingC) Cross-Linking
Polymer chains are cross - linked or attached byPolymer chains are cross - linked or attached by
a cross - linking agent such as glycola cross - linking agent such as glycol
dimethaerylate.dimethaerylate.
Through primary and small degree of crossThrough primary and small degree of cross
linking will limit the amount of movements oflinking will limit the amount of movements of
the polymer chains relative to each other.the polymer chains relative to each other.
When the material is stressed the deformationWhen the material is stressed the deformation
is elastic rather than plastic.is elastic rather than plastic.
15. CharacteristicCharacteristic
1.1. Higher strength and hardness.Higher strength and hardness.
2.2. Higher resistance to crazing which mayHigher resistance to crazing which may
be due to Alcohol drinking or solventsbe due to Alcohol drinking or solvents
3.3. It is the best type used for construction ofIt is the best type used for construction of
denture base and artificial teethdenture base and artificial teeth
4.4. Low water sorptionLow water sorption
16. PolymerizationPolymerization::
The chemical reaction by which polymers are prepared fromThe chemical reaction by which polymers are prepared from
monomersmonomers..
Condensation polymerization
Occurs when two molecules react to form a large molecules
with the elimination of smaller molecule
)Often but not always water(
Addition polymerization
Occurring when a reaction between two molecules
)either the same to form a homopolymer or dissimilar to
form heteropolymer(
produces a large molecule without the elimination of
a smaller molecule such as water
17. Types of polymerizationTypes of polymerization
Most polymerization reactions are of two types condensationMost polymerization reactions are of two types condensation
and addition polymerization.and addition polymerization.
1)Condensation polymerization:1)Condensation polymerization:
The reaction between two molecules to form a largerThe reaction between two molecules to form a larger
molecule with the elimination of a smaller such as watermolecule with the elimination of a smaller such as water
as a by product.as a by product.
condensationcondensation
Polymer + by productPolymer + by product
MonomerMonomer polymerizationpolymerization
ExExample is the polysulphide rubber impression material.ample is the polysulphide rubber impression material.
18. 22((Addition polymerizationAddition polymerization
The reaction between two molecules to giveThe reaction between two molecules to give
a larger molecule without the eliminationa larger molecule without the elimination
of a smaller molecule (no by-product).of a smaller molecule (no by-product).
No change in composition takes place, theNo change in composition takes place, the
structure of the monomer is repeated manystructure of the monomer is repeated many
times in the polymer e.g.times in the polymer e.g.
Poly (ethylene), poly (acrylic acid),Poly (ethylene), poly (acrylic acid),
polymethacrylic acid) poly (methacrylate).polymethacrylic acid) poly (methacrylate).
19. STAGESSTAGES OF ADDITIONOF ADDITION
POLYMERIZATIONPOLYMERIZATION
Initiation
Activation and
initiation (by free
radical mechanism)
STAGES OF ADDITION POLYMERIZATIONSTAGES OF ADDITION POLYMERIZATION
TerminationPropagation
CBA
Direct coupling
Exchange of a hydrogen atom
20. A) Activation and initiationA) Activation and initiation
A free radical is a compound with an unpairedA free radical is a compound with an unpaired
(unshared )electron (very reactive )(unshared )electron (very reactive )
The symbol (c= c) represents four electrons theThe symbol (c= c) represents four electrons the
monomer itself become free radical Benzoyelmonomer itself become free radical Benzoyel
peroxide is a substance most commonly used toperoxide is a substance most commonly used to
generate free radicals before initiationgenerate free radicals before initiation
The activation is done by light, heat or by a chemicalThe activation is done by light, heat or by a chemical
compound such as dimethyl paratoluidine. In thiscompound such as dimethyl paratoluidine. In this
way the peroxide decomposes giving up freeway the peroxide decomposes giving up free
radicals to initiate the polymerization reaction .radicals to initiate the polymerization reaction .
22. B) PropagationB) Propagation
The chain reactions continues with the evolutionThe chain reactions continues with the evolution
of heat until all the monomer has beenof heat until all the monomer has been
changed to a polymerchanged to a polymer And so onAnd so on
R1M +M + R1MM + M +R1MMMR1M +M + R1MM + M +R1MMM
R1MN where n is any integral number.R1MN where n is any integral number.
polymer free radical + monomerpolymer free radical + monomer growing chaingrowing chain
23. C) TerminationC) Termination
The reaction terminated either byThe reaction terminated either by
a) Direct couplinga) Direct coupling
This occurs when two free radicals reactThis occurs when two free radicals react
to form a stable moleculeto form a stable molecule
1- R1MN + R2MM1- R1MN + R2MM R1MNR1MN R2MMR2MM
b) Exchange of a hydrogen atomsb) Exchange of a hydrogen atoms
The chain reactions can be terminated eitherThe chain reactions can be terminated either
by direct coupling or by the exchange ofby direct coupling or by the exchange of
a hydrogen atom.a hydrogen atom.
24. Chain transferChain transfer
H H H H by transfer of
R1Mn – C – C + R2Mm – C – C
H H H H a hydrogen atom
H H H H
R1Mn – C = C + R2Mm – C – C - H
H H H
25. Factors associated withFactors associated with
polymerizationpolymerization
A) Evolution of heat as theA) Evolution of heat as the
reactions is strongly exothermicreactions is strongly exothermic
due to breaking of bonds.due to breaking of bonds.
B) Reduction in volume.B) Reduction in volume.
26. Inhibition of polymerizationInhibition of polymerization
Any impurity in the monomer which can reactAny impurity in the monomer which can react
with free Radicals will inhibit or retard thewith free Radicals will inhibit or retard the
polymerization reactionpolymerization reaction
It can react either with the activated initiatorIt can react either with the activated initiator
or any activated nucleus or with an activatedor any activated nucleus or with an activated
growing chain to prevent further growthgrowing chain to prevent further growth
27. The presence of such inhibitors influences theThe presence of such inhibitors influences the
length of the initiation period, as well aslength of the initiation period, as well as
the degree of polymerization.the degree of polymerization.
The addition of small amount of inhibitorThe addition of small amount of inhibitor
(Hydroquinone) to the monomer(Hydroquinone) to the monomer
(Methyl methacrylate)(Methyl methacrylate)
will inhibit polymerization if no chemicalwill inhibit polymerization if no chemical
initiator is present and it will retard theinitiator is present and it will retard the
polymerization in the presencepolymerization in the presence
of an initiator.of an initiator.
28. Factors affecting the properties ofFactors affecting the properties of
polymerspolymers
Many factors affect the properties of polymersMany factors affect the properties of polymers
1.1. Chemical composition of the chain.Chemical composition of the chain.
2.2. Degree of polymerization.Degree of polymerization.
3.3. The number of branches andThe number of branches and
4.4. The cross – links between polymer chainsThe cross – links between polymer chains..
29. In generalIn general
Longer chains and higher molecular weight polymersLonger chains and higher molecular weight polymers
characterized bycharacterized by
(a) Increased strength, hardness Brittleness and(a) Increased strength, hardness Brittleness and
stiffnessstiffness
(b) Increased resistance to creep.(b) Increased resistance to creep.
For example composite resins highly cross- linkedFor example composite resins highly cross- linked
matrix in which large number of strong covalentmatrix in which large number of strong covalent
linkages between chains transforms the moleculeslinkages between chains transforms the molecules
into a rigid very high molecular weight materialinto a rigid very high molecular weight material
resulting strength, stiffness and withstand occlusalresulting strength, stiffness and withstand occlusal
stresses.stresses.
30. In contrastIn contrast
Elastomeric impression materials composed ofElastomeric impression materials composed of
individual coiled chains with just few cross- linksindividual coiled chains with just few cross- links
this type of molecular structure permits the largethis type of molecular structure permits the large
scale uncoiling and recoiling of chains that givesscale uncoiling and recoiling of chains that gives
these materials high flexibility.these materials high flexibility.
Two basic properties which characterize polymersTwo basic properties which characterize polymers
are glass transition temperature (Tare glass transition temperature (Tgg))
and melting temp.and melting temp.
(T(Tgg ) Is the temperature at which the polymer ceases) Is the temperature at which the polymer ceases
to be glassy , brittle and become rubber – like.to be glassy , brittle and become rubber – like.
31. T g = MwT g = Mw
Molecular weight is another factor which affectsMolecular weight is another factor which affects
(T(T gg))
The two properties is related by an equation:The two properties is related by an equation:
32. Co- polymerizationCo- polymerization
To modify the properties of the polymer , use two orTo modify the properties of the polymer , use two or
more chemically different monomers such asmore chemically different monomers such as
copolymer process enabled chemists tocopolymer process enabled chemists to
““ tailor – make “ molecules of predicted properties fortailor – make “ molecules of predicted properties for
special applications e.g.special applications e.g.
Addition of sufficient amounts of octyl methacrylateAddition of sufficient amounts of octyl methacrylate
results in a copolymer that is soft and flexible atresults in a copolymer that is soft and flexible at
mouth temp.mouth temp.
And that has been used as a soft linerAnd that has been used as a soft liner
1.1. Hydroxyethyl methacrylate increase water sorptionHydroxyethyl methacrylate increase water sorption
and wetability of the copolymer by saliva .and wetability of the copolymer by saliva .
The material become soft and flexible if placed inThe material become soft and flexible if placed in
water or saliva It is used as soft contact lenseswater or saliva It is used as soft contact lenses
and as soft liner for denturesand as soft liner for dentures
33. CROSS-LINKING
Is a chemical bond formed between polymer chains.Is a chemical bond formed between polymer chains.
A chemical compound with two double bonds perA chemical compound with two double bonds per
molecules can act as cross-linking agent since eachmolecules can act as cross-linking agent since each
C =C bond can react with different chain.C =C bond can react with different chain.
This product has superior properties an example isThis product has superior properties an example is
ethylene glycol dimethacrylate .ethylene glycol dimethacrylate .
Small degree of cross-linking limits the amount of theSmall degree of cross-linking limits the amount of the
polymer chains when the material is stressed.polymer chains when the material is stressed.
The deformation is elastic rather than plastic.The deformation is elastic rather than plastic.
The polymer have high glass transition temperature.The polymer have high glass transition temperature.
The polymer is harder more brittle and moreThe polymer is harder more brittle and more
resistance to the action of solventsresistance to the action of solvents
34. PlasticizersPlasticizers
Liquids are able to penetrate between the chains ofLiquids are able to penetrate between the chains of
polymer .The molecules become further apart and thepolymer .The molecules become further apart and the
forces between them become less.forces between them become less.
such liquids is called plasticizerssuch liquids is called plasticizers
CharacteristicsCharacteristics
(a ) Soften the material(a ) Soften the material
(b) Make it more flexible by lowering its glass transition(b) Make it more flexible by lowering its glass transition
temp . if sufficient plasticizers is added to a polymer Ittemp . if sufficient plasticizers is added to a polymer It
becomes flexible , rubbery in the mouth below mouthbecomes flexible , rubbery in the mouth below mouth
temperature. So it is used in producing soft liningtemperature. So it is used in producing soft lining
materialsmaterials
35. Types of copolymersTypes of copolymers
Random copolymer
In which the two monomers enter into the copolymer in a relatively random manner along the co polymer
chain:
M1-M2 – M2 - M2 – M1 – M2-M2-M1
Alternating copolymer
Contains the two monomer units in equimolar amount in regular alternating distribution .
M1-M2 – M1 - M2
Block copolymer
Is a linear copolymer with one or more long uninterrupted sequences of each polymeric species
M1-M1 – M1- M1 – M2 – M2 –M2 – M2
Graft copolymer
Is a branched copolymer with a back bone of one monomer to which
are Attached one or more side chains of another monomer .
M1-M1 – M1- M1 –M1
M1
M1
M1
36. Application of polymers inApplication of polymers in
dentistrydentistry
Denture base materials.Denture base materials.
Artificial teeth.Artificial teeth.
Tooth restorativeTooth restorative
materials.materials.
Cements.Cements.
Crown and bridgeCrown and bridge
facings.facings.
Impression materials.Impression materials.
DiesDies..
Endodontic fillingsEndodontic fillings..
Mouth protectorsMouth protectors..
Maxillofacial prosthesisMaxillofacial prosthesis..
VarnishesVarnishes,,
pit and fissure sealantpit and fissure sealant
38. Dental Bio-materialsDental Bio-materials
Ass. Prof. Dr. Mohamed Abed el-Aziz SouhailAss. Prof. Dr. Mohamed Abed el-Aziz Souhail
Head of Dental Bio-material Department,Head of Dental Bio-material Department,
Faculty of Dental Medicine,Faculty of Dental Medicine,
Al- Azhar University.Al- Azhar University.
39. Non – metallic Denture base materialsNon – metallic Denture base materials
Heat cured
PMMA
Auto polymerized
PMMA
Injection
Molded
Conventional
High impact
PMMA
Polycarbonate
Nylon
Unfilled
Reinforced
Glass fiberCarbon
41. Acrylic resinAcrylic resin
Is made by addition processIs made by addition process
free radical additionfree radical addition
polymerizationpolymerization
a denture consists of denture
base and artificial teeth,
different materials have been
made to construct a denture
bases
42.
43. The ideal requirement of denture baseThe ideal requirement of denture base
materialmaterial
1-Acrylic resin more aesthetics.1-Acrylic resin more aesthetics.
2-High impact strength , fatigue strength, stiffness and hardness.2-High impact strength , fatigue strength, stiffness and hardness.
3-Good thermal conductivity to maintain healthy tissues.3-Good thermal conductivity to maintain healthy tissues.
4- Low density to help denture retention.4- Low density to help denture retention.
5-Easy to repair.5-Easy to repair.
6-Easy to manipulate.6-Easy to manipulate.
7-Goog shelf life.7-Goog shelf life.
8-Inexpensive.8-Inexpensive.
9-Dimensionally stable and maintain surface details.9-Dimensionally stable and maintain surface details.
10-Good retention to base metals ,porcelain teeth and acrylic teeth.10-Good retention to base metals ,porcelain teeth and acrylic teeth.
11-Radio-opaque to be seen in x-ray if swallowed.11-Radio-opaque to be seen in x-ray if swallowed.
21-Not toxic or irritant to the oral tissues.21-Not toxic or irritant to the oral tissues.
44. Composition of acrylicComposition of acrylic
resinresin
An acrylic resin denture is made by theAn acrylic resin denture is made by the
process of free radical additionprocess of free radical addition
polymerization to formpolymerization to form
polymethylmethacrylate.polymethylmethacrylate.
The monomer is methylmethacrylate.The monomer is methylmethacrylate.
The resins are available in either heat curedThe resins are available in either heat cured
or self-cured.or self-cured.
45. Composition Of Heat Cured Resin
Powder
1.1. Beads or granules of polymethyl methacrylate.Beads or granules of polymethyl methacrylate.
The granules dissolve more rapidly and henceThe granules dissolve more rapidly and hence
shorten the dough time.shorten the dough time.
2.2. Benzyl peroxide- Initiator.Benzyl peroxide- Initiator.
3.3. Plasticizers - dibutyl phthalate. to produce a lessPlasticizers - dibutyl phthalate. to produce a less
brittle.brittle.
4.4. Opacifiers- Titanium / zinc oxides .to be seen inOpacifiers- Titanium / zinc oxides .to be seen in
the x-ray if swallowed.the x-ray if swallowed.
5.5. Pigments / dyes to give the natural tissue likePigments / dyes to give the natural tissue like
appearance.appearance.
6.6. Synthetic fibers - nylon / Acrylic. to simulateSynthetic fibers - nylon / Acrylic. to simulate
blood vessels of the oral tissues.blood vessels of the oral tissues.
46. LiquidLiquid
1.1. Methylmethacrylate monomerMethylmethacrylate monomer
2.2. Inhibitor - Hydroquinone to reactInhibitor - Hydroquinone to react
with any free radical that may formwith any free radical that may form
in the liquid.in the liquid.
3.3. Cross - linking agent - ethyleneCross - linking agent - ethylene
glycol dimethacrylate cross linkingglycol dimethacrylate cross linking
agent ,to improve the mechanicalagent ,to improve the mechanical
propertiesproperties..
47. ManipulationManipulation
1-proportioning:1-proportioning: The polymer /powder ratio is 3:1 byThe polymer /powder ratio is 3:1 by
volume or 2.5:1 by weight,volume or 2.5:1 by weight,
Using this ratio will decrease the polymerizationUsing this ratio will decrease the polymerization
shrinkage from 21 % to 6-7 %shrinkage from 21 % to 6-7 %
Too Much PowderToo Much Powder
Could result in under - wetting of the polymer beads byCould result in under - wetting of the polymer beads by
the monomer resulting in a weak material .the monomer resulting in a weak material .
Too Much MonomerToo Much Monomer
will produce excessive polymerization shrinkage and awill produce excessive polymerization shrinkage and a
loss of quality of fit to the denture bearing area surfaceloss of quality of fit to the denture bearing area surface
48. Polymerization stagesPolymerization stages
1.1. Sandy stageSandy stage :It is incoherent mass is formed like sand:It is incoherent mass is formed like sand
2.2. Sticky or fibrous stage: The polymer begins toSticky or fibrous stage: The polymer begins to
dissolve in the monomer .dissolve in the monomer .
3.3. Dough stage :The material becomes smooth and doesDough stage :The material becomes smooth and does
not stick to the mixing gar or hands and it is easilynot stick to the mixing gar or hands and it is easily
manipulatedmanipulated ,,this is the ideal stage for packing.this is the ideal stage for packing.
4.4. Rubbery stage: The material can not be shaped.Rubbery stage: The material can not be shaped.
5.5. Stiff stage:Stiff stage: If the material is left longer it becomesIf the material is left longer it becomes
stiff.stiff.
49. PackingPacking
When the material reaches the dough stage it is readyWhen the material reaches the dough stage it is ready
for packing in the flaskfor packing in the flask
If packed in sandy or sticky stages the material will beIf packed in sandy or sticky stages the material will be
of high fluidity and will flow out of the flask resultingof high fluidity and will flow out of the flask resulting
in denture porosity.in denture porosity.
If packed in rubbery o stiff stage, the material will notIf packed in rubbery o stiff stage, the material will not
flow under pressure, this result denture withoutflow under pressure, this result denture without
details and with fractured teeth.details and with fractured teeth.
The acrylic should be packed with excess to decreaseThe acrylic should be packed with excess to decrease
polymerization shrinkage from 7 %to0.2 %polymerization shrinkage from 7 %to0.2 %
Sufficient pressure should be applied on the mold toSufficient pressure should be applied on the mold to
avoid shrinkage porosity.avoid shrinkage porosity.
50. CuringCuring
After packing the flask underAfter packing the flask under pressure is placed inpressure is placed in
water path at 72water path at 72 00C using eitherC using either
long or short curing cycleslong or short curing cycles
Under curing will result in a denture with highUnder curing will result in a denture with high
residual monomer lead to tissue irritation andresidual monomer lead to tissue irritation and
inferior properties.inferior properties.
Over curing will result in boiling of the monomerOver curing will result in boiling of the monomer
(100.3(100.3 00C )C )due to added of heat of polymerizationdue to added of heat of polymerization
and as a result the monomer will vaporize leavingand as a result the monomer will vaporize leaving
pores inside the denture (gaseous porosity).pores inside the denture (gaseous porosity).
51. Cooling- Deflasking- Finishing andCooling- Deflasking- Finishing and
polishingpolishing
The flask should be cooled slowly to release the internal stressesThe flask should be cooled slowly to release the internal stresses
DeflaskingDeflasking
Should be done with care to avoid breaking of the denture.Should be done with care to avoid breaking of the denture.
Finishing and polishingFinishing and polishing
PropertiesProperties
Residual monomerResidual monomer
Even in a properly cured acrylic denture,0.2- 0.5 %of theEven in a properly cured acrylic denture,0.2- 0.5 %of the
monomer remains curing at too low temperature or formonomer remains curing at too low temperature or for
too short time results in higher residual monomer thistoo short time results in higher residual monomer this
should be avoided because it is more irritant to the oralshould be avoided because it is more irritant to the oral
tissues, it act as plasticizer and make the denture moretissues, it act as plasticizer and make the denture more
flexible and weakerflexible and weaker
52. Types of PorosityTypes of Porosity
It is undesirable effects on both strength and opticalIt is undesirable effects on both strength and optical
properties of the dentureproperties of the denture
53. Water sorptionWater sorption
Acrylic dentures absorb water by 2% of its weight, eachAcrylic dentures absorb water by 2% of its weight, each
1% increase in weight causes a liner expansion of 0.221% increase in weight causes a liner expansion of 0.22
%.%.
Also drying out the acrylic dentures is associated withAlso drying out the acrylic dentures is associated with
shrinkage.shrinkage.
Water sorption is an advantage to compensate theWater sorption is an advantage to compensate the
processing shrinkageprocessing shrinkage
which is 0.44 % (the polymerization and the thermalwhich is 0.44 % (the polymerization and the thermal
shrinkage occurring when cooling from (72shrinkage occurring when cooling from (72 00C toC to
2020 00C )So dentures should be kept wet all the time whenC )So dentures should be kept wet all the time when
not in service.not in service.
54. CrazingCrazing
Is an actual mechanical separation of the polymer chainsIs an actual mechanical separation of the polymer chains
or group of chains under tensile stresses.or group of chains under tensile stresses.
And it has weakening effect on the denture.And it has weakening effect on the denture.
Causes:Causes:
a- Continuous stresses due to repeated drying and wettinga- Continuous stresses due to repeated drying and wetting
of the denture.of the denture.
b-b- Difference in coefficiency of thermal expansionDifference in coefficiency of thermal expansion
between acrylic denture base and porcelain teeth.between acrylic denture base and porcelain teeth.
c- Action of solvents e.g. alcohol ,acetone chloroform ,c- Action of solvents e.g. alcohol ,acetone chloroform ,
monomer when a denture is repaired and may causemonomer when a denture is repaired and may cause
crazing.crazing.
55. Mechanical propertiesMechanical properties
Thermal conductivity:Thermal conductivity:
Is very low thermal conductivity, and thisIs very low thermal conductivity, and this
is disadvantages.is disadvantages.
Coefficient of thermal expansion:Coefficient of thermal expansion:
It is quite high and this does not problem,It is quite high and this does not problem,
except that porcelain teeth in denture baseexcept that porcelain teeth in denture base
may gradually loosen and lost.may gradually loosen and lost.
UsesUses: Denture bases and artificial teeth.: Denture bases and artificial teeth.
56. Control Of ColorControl Of Color
The coloring pigment is usually incorporate in theThe coloring pigment is usually incorporate in the
polymer powder, but in some cases it may simply bepolymer powder, but in some cases it may simply be
on the surface of the polymer beads and may beon the surface of the polymer beads and may be
washed off by too rapid contact of the monomer inwashed off by too rapid contact of the monomer in
this case.this case.
Produce too light a shadProduce too light a shad
Should be added to the monomer slowly too littleShould be added to the monomer slowly too little
powder will mould -liningpowder will mould -lining
Separating medium must be employed to preventSeparating medium must be employed to prevent
adhering to the mould nowadays.adhering to the mould nowadays.
The separating medium is usually a solution of sodiumThe separating medium is usually a solution of sodium
alginate, although some still recommend the use ofalginate, although some still recommend the use of
tinfoil.tinfoil.
57. ProcessingProcessing
Two problems in the processing of acrylics for theTwo problems in the processing of acrylics for the
dentures .dentures .
1) Porosity: Is the presence of processing strains .1) Porosity: Is the presence of processing strains .
During Processing Stage
Causes of porosityCauses of porosity
a)a) Polymerization shrinkagePolymerization shrinkage
(Contraction porosity )(Contraction porosity )
1.1. Volatilization of the monomerVolatilization of the monomer
( gaseous porosity( gaseous porosity
58. Contraction PorosityContraction Porosity
A monomer contracts by some 20% during processing byA monomer contracts by some 20% during processing by
using powder / liquid system the contraction isusing powder / liquid system the contraction is
minimized 5-8% (high linear shrinkage ) volumetricminimized 5-8% (high linear shrinkage ) volumetric
contraction (1.2-2%) thermal contraction (0.2-0.5%)contraction (1.2-2%) thermal contraction (0.2-0.5%)
from curing contraction .from curing contraction .
at the curing temperatureat the curing temperature
The resin is able to flow into the spaces created by theThe resin is able to flow into the spaces created by the
curing contraction.curing contraction.
Cold cure resins should give a better fit for the denture asCold cure resins should give a better fit for the denture as
the processing temp . is considerably lower ( aroundthe processing temp . is considerably lower ( around
60co compared to 100co for the heat cured resin ).60co compared to 100co for the heat cured resin ).
59. Localized PorosityLocalized Porosity
Due to poor mixing of the components or to packing theDue to poor mixing of the components or to packing the
mould before the doughy stage is reached gaseousmould before the doughy stage is reached gaseous
porosity .porosity .
due to exothermic reaction the temp, of the resindue to exothermic reaction the temp, of the resin
increase above the boiling temp., which is just aboveincrease above the boiling temp., which is just above
100 co .100 co .
Cracks
The relief of internal strain can produce tiny surfaceThe relief of internal strain can produce tiny surface
crakes in the resin these are known as crazes and oncrakes in the resin these are known as crazes and on
be identified by a hazy or foggy appearance the crakesbe identified by a hazy or foggy appearance the crakes
may be visible .may be visible .