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CHAPTER #2. Polymers and Polymerization. Polymers. Polymers are large molecules that are formed by linking many smaller molecules called monomers . The monomers and types of linkages can be controlled to produce polymers with specific properties (strength, flexibility etc.)
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CHAPTER #2 Polymers and Polymerization
Polymers • Polymers are large molecules that are formed by linking many smaller molecules called monomers. • The monomers and types of linkages can be controlled to produce polymers with specific properties (strength, flexibility etc.) • There are natural polymers such as carbohydrates, proteins, and DNA; and synthetic polymers such as plastics. • Monomers may be identical or they may be different molecules arranged in a repeating pattern
Polymerization & Polymers • Polymerization is the process of linking monomers to form a polymer. • Polymers are of two types: • Addition Polymers • Condensation polymers
Addition Polymers • Result from the addition reactions of small subunits containing double or triple carbon – carbon bonds • The small monomers link because the multiple bonds break apart as the molecules join Example • Addition polymerization of ethene to form polyethene (aka polyethylene)
Condensation Polymers • Monomers are linked together by formation of ester or amide bonds • Water is usually produced in this reaction • Each monomer must have two functional groups – one at each end of the molecule • Condensation polymers containing amide bonds are called nylons, while those containing ester bonds are called polyesters Example: • 1,6-diaminohexane + hexanedioic acid (aka adipic acid) forms nylon 6, 6 • Video of nylon formation
Answer the following questions • Addition polymers are often used for containers for chemicals, solvents and foods. Explain why. • Why are plastics flexible and moldable? • Teflon, an addition polymer, is used for a nonstick surface for cookware. What property of Teflon explains the nonstick ability of this polymer? • Plexiglas, an addition polymer, is often used in place of glass, but is easily damaged by organic solvents such as acetone. Why? • Polymethylacrylate, a polymer of sodium methylacrylate, is used in disposable diapers. How does this polymer able to absorb up to 400 times its mass in water?
Check your Understanding!! • The proper term used to describe a polymer made by combining large numbers of identical monomers is which of the following? a. natural polymer b. addition polymer c. thermoset polymer d. condensation polymer e. thermoplastic polymer ANS: B
Read Chapter 2.1 and 2.2 and answer the questions in the chapter.