Question

3. a. Use the open literature to give three examples of each polymers formed by step (condensation) polymerization and by add ition (chain) polymerization. Describe the monomers, structural unit(s) and repeating unit in each case.

Answer 1

L'olymer is a large molecule, which is forin small repeating units which are known as monomer (a) xample of a synthetic addition polymer: In addition polytheri Ulior, the TICHICILLET als are ucided clirecủy to each other, hooking together like boxcars on a train to form the polytice. The TOTKOVNICTS for taking addition polyers usually contain one or more C-C double bond (a)A synthetic condensation polymer: Condensation polymers are formed by condensation polymerization caction between monomers. Unlike addition polymerization reactions, condensation polymerization reactions do not depend on the presence of a double boud in the reactie molecules. Rather, Condensation) polymerization reactions generally require two different functional roups present in the sanne Toomier in wo dilleretil monomers. Each of the two monomers has a functional group at cach end of the monomer. As the functional groups at cach end of One monomer react with the groups of the other tormer, long- chain condensation polymers are produced. For example, molecule with two carboxylic acid groups (-COOH), such as tereplıthalic acid, and other molecules with two alcohol groups, such as cthylene glycol, can react with cach other at both ends to fon ester linkages. Water is the other product of this condensation polymerization reaction it is proceed during the formation of cach esler litikuge in the polyiller. Polyethylene- The simplest monomer for addition polymerization is cthylenece C,, which polymerizes to form polyethylene. When heated to 100 to 250°C at a pressure of 1000 to 3000 arm in the presence of a catalyst, etylene forts polyethylene chats with our cusses of up to many thousands Polymerization involves three steps initiation, propagation, and chait tertination For example Polyvinyl acetate is a polymer of vinyl acetate. It is also known as ethenyl ethanoate. : #00C-C H D0H+: H.CH, CH, CH ) 1100C CTI-COO-CH1, C11-00CC,1,COOCII, CHI, O 13.0 The growing replich ulic acid-ethylene glycol polyimler ethery. ethanoate It is used as adhesive, latex and paints. The structural formula for a three-monomer segment of polyvinyl acetate is as follows: Because this product has a -COOH group on one end an - OH group on the other end, the -COOH can react with an OH group of another ethylene glycol molecule. Similarly, the remaining alcohol group on the ester can react with another terephthalic acid molecule. This process continues, fonning long chain of poly (ethylene terephthalate). a polyester commonly known as PET. Polyamides are made by condensing carboxylic acid (-COOH) and amine (NH) functional groups. Nylon : This is a Polyartides polymer which is foru by condensing curboxylic acid (-COIL) und LLLLC (-NH) functional groups Three-monomer segment of polyvinyl acetate When polymer is fomed only one type of monomer then polymer is culled lonio-polyiler. For exatrple PVC. is a turno-polymer, formed by polymerization of vinyl chloride. Polypropylene is also homo-polymer of propylene. The structural formula for a Urre-OUTLOOT segment of polypropylene is as follows: -[c. (C.H,1,C. NHỊCH. NH].- Nylon The most comm. exluple of this class of sytilitelic polymers is byloma; prepared from adipic acid a di-carboxylic acid) and lexuelylenediante (u dale). When polymer is formed more than one type of monomer then polymer is called copolyiket. Kevlar is a copolyTIKT of 1,4 Watu benzte und 1.1-dicarboxybene. In the kevlar these are polymerized in the alterate tend. A c this chain is following: Three-IILOILICT segtett of Polypropylene Segment of Kevlar The structures of 1.1 diaminobenzne and 1,1-dicarboxybene are as follows: The overall reaction for the condensation reaction of Kevlar polymer is us follows: