Copolymers
Copolymers are polymers composed of two or more different monomers. They are classified based on the arrangement of their monomer units, which can be random, alternating, block, or graft. Copolymers are widely used in various industries, including plastics, adhesives, coatings, and biomedical applications, due to their ability to combine the properties of different monomers.
8 Key excerpts on "Copolymers"
eBook - ePubPrinting on Polymers
Fundamentals and Applications
- Joanna Izdebska-Podsiad?y, Sabu Thomas(Authors)
- 2015(Publication Date)
- William Andrew(Publisher)
...Polymers 33 2.4.1.1 Polyethylene 34 2.4.1.2 Polypropylene 34 2.4.1.3 Polyvinylchloride 35 2.4.1.4 Polystyrene 35 2.4.2 Applications of Engineering Polymers 35 2.4.2.1 Polyamides 35 2.4.2.2 Polybutylene Terephthalate 35 2.4.2.3 Acrylonitrile Butadiene Styrene 36 2.4.2.4 Polyoxymethylene or Polyacetals 36 2.4.3 Polymers for Specialty Applications 36 2.4.3.1 Polymers in Electronic Applications 37 2.4.3.2 Biomedical Applications 37 2.4.3.3 Polymers in Sensor Applications 37 2.5 Conclusion 37 References 37 2.1. Introduction Polymers are materials of the twentieth century. They have substituted other materials in most of the applications because of their wide property spectrum. Nowadays, most of the articles that we use in our day-to-day lives, such as carry bags, packing materials, pens, beverage bottles, containers, cloths, furniture, adhesives, and syringes, are made of polymers. Polymers also have found application in engineering components such as gears and structural components. Their properties can be easily tuned by the selection of a proper synthetic route or conditions and incorporation of additives during product manufacturing. Most polymers can be processed very easily in comparison with other classes of materials. This enables the manufacturer to produce a larger number of goods with less energy consumption. Even though many concerns are arising on the disposal of polymeric waste, it is impossible to find a class of materials that can substitute them. The term polymer is derived from two Greek words: poly means many, and meros means parts. As the name suggests, polymers are large molecules formed by the chemical reaction of smaller molecules or repeating units. These repeating units are termed monomers. The size of the molecule or molar mass can vary from thousands to millions, depending on the monomer- and polymer-synthesizing method. Animal and plant bodies contain many polymeric materials such as cellulose, polypeptides, and starch...
eBook - ePub- Vincent Voet, Jan Jager, Rudy Folkersma(Authors)
- 2021(Publication Date)
- De Gruyter(Publisher)
...2 Introduction to polymer science 2.1 Classification The success of plastics can be attributed to their low costs and wide range of properties that can be changed by tweaking the macromolecular structure. This unique structure–property relationship will receive specific attention in the remainder of this chapter. We will start by discussing various ways to categorize polymer materials. The term polymer is derived from the Greek words π o λ υ ´ ς (polus = “many”) and μ ε ´ ρ o ς (meros = “part”). Polymers can be defined as large molecules, sometimes referred to as macromolecules, composed of a large number of repeating units. The exact number required to meet the definition of a polymer depends on the size and chemical structure, but a good rule of thumb is at least 50 repeating units. Smaller molecules are named oligomers, which translates to “few parts”. The building blocks that form a polymer molecule are called monomers, literally meaning “one part”. Monomers can undergo polymerization, in which they react together to form a polymer chain or network structure. Polymerizations are the subject of Section 2.3. Considering the definition of a polymer, a tremendous amount of possibilities arise: flexible or stiff polymers, polymers derived from nature or those made in factories, polymers that absorb or repel water, polymers applied in airplanes or used in clothing, etc. To create some order, polymers are classified based on various categories, as displayed in Fig. 2.1. Figure 2.1 Classification of polymers based on origin, chemistry, (physical) properties, polymerization route, and application. 2.1.1 Origin A wide variety of macromolecules is present in nature. Polysaccharides like starch and cellulose are formed in plants, while proteins such as silk and casein can be found in animals. Polynucleotides, known as DNA and RNA, play a crucial role in storing, coding, expressing, and regulating genetic information...
eBook - ePub- James G. Speight(Author)
- 2010(Publication Date)
- Gulf Professional Publishing(Publisher)
...Chapter 14. Monomers, Polymers, and Plastics Contents 1. Introduction 499 2. Polymerization 501 3. Polymers 507 3.1. Chain length 511 3.2. Structure 511 3.3. Copolymers 514 3.4. Repeat unit placement 517 3.5. Chemical properties 522 3.6. Polymer degradation 522 3.7. Phase separation 523 3.8. Glass transition temperature 523 3.9. Molecular weight 525 4. Plastics 526 4.1. Classification 527 4.2. Chemical structure 529 4.3. Properties 530 4.3.1. Mechanical properties 530 4.3.2. Chemical properties 531 4.3.3. Electrical properties 533 4.3.4. Optical properties 533 4.4. Thermoplastics 534 4.5. Hydrocarbon fibers 535 References 536 1. Introduction Monomers are the basic molecular form in which polymers and plastics are produced. Polymers consist of repeating molecular units which usually are joined by covalent bonds. Polymerization is the process of covalently bonding the low-molecular-weight monomers into a high-molecular-weight polymer. A polymer may also be referred to as a macromolecule (Ali et al., 2005). For a molecule to be a monomer, it must be at least bifunctional insofar as it has the capacity to interlink with other monomer molecules. While not truly bifunctional in the sense that they contain two functional groups, olefins have the ability to acts as bifunctional molecules though the extra pair of electrons in the double bond. A polymer may be a natural or synthetic macromolecule comprised of repeating units of a smaller molecule (monomers). The terms polymer and plastic are often used interchangeably but polymers are a much larger class of molecules which includes plastics, plus many other materials, such as cellulose, amber, and natural rubber. Examples of hydrocarbon polymers include polyethylene and synthetic rubber (Schroeder, 1983). In the current context, a monomer is a low-molecular-weight hydrocarbon molecule that has the potential of chemically bonding to other monomers of the same species to form a polymer...
eBook - ePubFundamentals of Polymer Science
An Introductory Text, Second Edition
- Michael M. Coleman, Paul C. Painter(Authors)
- 2019(Publication Date)
- CRC Press(Publisher)
...CHAPTER 1 The Nature of Polymeric Materials “He fixed thee mid this dance of plastic circumstance” —Robert Browning A. WHAT ARE POLYMERS—WHAT IS POLYMER SCIENCE? Simply stated, polymers are very large molecules (macromolecules) that are comprised or built up of smaller units or monomers. The arrangements of these units, the various types of chains that can be synthesized and the shapes that these chains can bend themselves into, result in a class of materials that are characterized by an enormous and intriguing range of properties. Some of these are unique to polymers (e.g., rubber elasticity) and, as we shall see, are simply a consequence of their size and chain-like structure. Polymer science is also a relatively new discipline and one that is characterized by extraordinary breadth. It involves aspects of organic chemistry, physical chemistry, analytical chemistry, physics (particularly theories of the solid state and solutions), chemical and mechanical engineering and, for some special types of polymers, electrical engineering. Clearly, no one person has an in-depth knowledge of all these fields. Most polymer scientists seek a broad overview of the subject that is then usually supplemented by a more detailed knowledge of a particular area. This book is a first step towards the former and to give a flavor for the diversity of this subject matter we will commence with an outline of some of the areas we will cover. Polymer Synthesis Many polymer scientists think that it is unlikely that we will ever again see any new thermoplastic take the world by storm (i.e., achieve levels of production comparable to polyethylene or polystyrene), but it should be kept in mind that similar things were being said round about 1950, just before high density polyethylene and isotactic polypropylene made their debut (some of this terminology will be defined shortly). Today, there are two good reasons to think they may be right, however...
- Shashanka Rajendrachari, Orhan Uzun(Authors)
- 2021(Publication Date)
- Bentham Science Publishers(Publisher)
...Polymers R. Shashanka, Orhan Uzun Abstract In the present chapter, we have discussed the classification of polymers, structure, properties, fabrication process, and polymerization mechanism. Generally, polymers are made up of a series of molecules joining together and the average molecular weight of chains ranges from 10,000 to more than one million. The process of chemically joining the monomers together to create giant molecules is called polymerization. In polymers, atoms are joined together by a strong bond called covalent bonding. Many of the polymers are organic (carbon-based polymers) and inorganic (non-carbon based polymers like polysiloxanes, polyphosphazene, polysilanes, etc.). Keywords: Addition and condensation polymerization, Bakelite, Branched and cross-linking polymers, Classification, Homo and co-polymers, Linear, Mechanisms, Molding techniques, Natural polymers, Nylon, Polymers, Properties of polymers, Polyethylene, PVC, Poly propylene, Synthetic polymers, Tacticity, Thermosetting and thermoplastics. 1. INTRODUCTION The word polymer comes from the Greek language “poly” meaning many and “mers” means units. A polymer is defined as a group of many units or it is a combination of a large number of monomers together to form a giant structure. Most of the time the word polymer is used for “plastic” also; but, all plastics are polymers, but not all polymers are plastics [ 2 ]. Fig. (1) shows the polymers [ 1 ]. Polyvinyl chloride (PVC), polyethylene, polymethyl methacrylate (PMMA), nylons, bakelite, etc. are some of the examples of polymers. Polymers are very popular due to their wide range of applications as mentioned below [ 1 ]: Automobile industries Constructional purposes Aerospace applications Medical applications Packaging applications Electronic goods etc. Fig. (1)) Polymers [ 1 ]. 2...
eBook - ePub- S.K. Duggal(Author)
- 2017(Publication Date)
- Routledge(Publisher)
...Chapter 15 POLYMERIC MATERIALS 15.1 Introduction 15.2 Polymerisation Mechanism 15.3 Depolymerisation 15.4 Rubbers 15.5 Plastics 15.6 Constituents of Plastics 15.7 Fabrication of Commercial Articles 15.8 Applications of Plastic 15.9 Properties of Plastics 15.10 Effect of Temperature on Mechanical Properties Exercises 15.1 Introduction High polymers, also known as macromolecules, are large molecules of colloidal dimensions (10 -3 to 10 -6 mm in diameter) have high molecular weight (10,000 to millions). Small molecules called monomers undergo polymerisation reaction and form macromolecules. The examples of polymeric materials are resins, plastics and rubbers. 15.2 Polymerisation Mechanism Polymerisation may be defined as the union of two smaller molecules of similar or different types with or without elimination of water resulting in the formation of new C-C linkages. The mechanism by which polymerisation takes place may be addition or condensation. A monomer for polymerisation should be bi- or poly functional, i.e. it must contain two or more functional groups. Some of the other functional groups are hydroxyl acid, amino acid, di-amino acid, di-acids, di-or polyalcohols. The structures depend on the functionability of monomers. In case of a bi-functional monomer there will be two reactive groups at its ends. These groups may align side by side to form a straight chain like molecule as shown in Fig. 15.1. The monomer units are linked by primary covalent bonds and the different chains are held together by secondary force of molecular attraction. However, during the chain growth side chains may also develop leading to branched chain molecules as shown in Fig. 15.2. In case of poly-functional groups the monomer molecules are connected to each other by covalent bonds and form a three-dimensional network (Fig. 15.3). Fig. 15.1 Linear Chain Polymer Formation by a Reaction of bi-functional Molecule Fig. 15.2 Branched-Chain Polymer Fig...
- Laurence W. McKeen(Author)
- 2019(Publication Date)
- William Andrew(Publisher)
...1 Introduction to Plastics and Polymers Abstract This chapter is an introduction to polymer chemistry. It includes polymerization chemistry and the different types of polymers and how they differ from each other. Discussed are the subjects of Copolymers, branching, cross-linking, steric hindrance, isomerism, crystallinity, and other factors that affect the molecular structures of the polymers used to make plastics. Since plastics are rarely “neat,” reinforcement, fillers, and additives are reviewed. The influence of molecular structure on properties is examined. A basic understanding of plastic and polymer chemistry will make the discussion of plastics easier to understand and it also provides a basis for the introductions of the plastic families in later chapters. Keywords Polymerization; isomers; molecular attractions; amorphous; crystallinity; additives The basic component of plastic and elastomer materials is polymer. The word polymer is derived from the Greek term “many parts.” Polymers are large molecules composed of many repeat units, called monomers that have been chemically bonded into long chains. Since World War II, the chemical industry has developed a large quantity of synthetic polymers to satisfy the material needs for a diverse range of products, including paints, coatings, fibers, films, elastomers, and structural plastics. Literally thousands of materials can be called “plastics,” although the term today is typically reserved for polymeric materials, excluding fibers, which can be molded or formed into solid or semisolid objects. As of the beginning of 2012, IDES The Plastics Web (http://www.ides.com) listed over 85,000 different grades of plastic from over 800 suppliers. There are three introductory chapters to this book. The first chapter is a review of polymer chemistry and plastic formulation. It lays the basis for the discussion on weather processes, property measurement, and all the data chapters...
eBook - ePubThe Science For Conservators Series
Volume 3: Adhesives and Coatings
- Conservation Unit Museums and Galleries Commission(Author)
- 2013(Publication Date)
- Routledge(Publisher)
...2 The chemistry of polymers A Long-chain polymers B Polymerisation C Network polymers D Some important characteristics of polymeric materials D1 Terminology D2 Relating properties to structure The chemistry of polymers polymer monomers long-chain molecules network polymers Polymer is the name given to very large molecules which contain hundreds, thousands, or even millions of atoms and are made up by the successive linking together of one or more types of small molecule. The small molecules are called monomers (from Greek words meaning single part) and they produce a polymer (many parts). Most of the properties of a polymer are strongly influenced by the way in which it is built up from its component monomers, and to help draw out this point it is useful to classify polymers into two types: those which form long-chain molecules and those which form one large continuous molecule consisting of a two-or three- dimensional network, that is, network polymers. In this chapter we will look at each of these in turn. A Long-chain polymers These have the simplest structure and can be envisaged as a poppet-bead necklace in which the monomers are the poppet-beads each of which has a stud that links to another bead, so enabling the long-chain polymer to be built up. Figure 2.1 Schematic representation of monomers (poppet beads) joining to form a polymer (necklace). covalent bond The simplest polymer like this is polyethylene. As its name implies, the monomer is ethylene. It has a double covalent bond : between the carbon atoms (see Book 1, Section 4C) which is highly reactive. In effect, one of these bonds provides the poppet-stud which links to a neighbouring molecule, which links to the next and so on, to create the long-chain polymer (Figure 2.2). Figure 2.2 polymerisation plasticisers The chemical process of joining the monomers together is called polymerisation. This will be looked at a bit more closely in the next section...
