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Condensation polymerisation. Characteristics. Occur via condensation reactions. A small molecule is eliminated – usually water . This means that the empirical formula of the polymer is not the same as that of the monomers.
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Characteristics • Occur via condensation reactions. • A small molecule is eliminated – usually water. • This means that the empirical formula of the polymer is not the same as that of the monomers. • Generally condensation polymers have two different monomers, each of which have two functional groups.
Terylene Benzene 1,4 di carboxylic acid Two different monomers; Ethan 1,2 diol
Alcohol and carboxylic acid groups react together to form esters. So the monomers are linked by ester bonds.
Free carboxylic acid group + H2O The unused functional group on each of the linked monomers allows the chain to keep growing… Free hydroxyl group.
As it contains many ester groups Terylene is known as a polyester. Giving a repeat; -[OC(O)-C6H4-C(O)OCH2CH2]-
Nylon Hexane 1,6 diamine Two monomers; Hexane 1,6 dioyl chloride
Amine and acid chloride groups react to link together by amide bonds, similar to peptide bonds in proteins.
Unreacted functional groups allow the chain to keep growing. Linking monoers with an amide bond. Free amine group Free acid chloride group On polymerisation a molecule of hydrogen chloride is removed.
Giving a repeat; [HN(CH2)6N(H)-C(O)(CH2)4(O)C-] As both monomers have6 carbon atomsthis is referred to asNylon 6,6.
Comparing nylon and proteins • 1) Nylon consists of two different monomers; • 2HN(CH2)6NH2 • Hexane 1,6 diamine • ClC(O)-(CH2)4-(O)CCl • Hexane 1,6 dioyl chloride • Proteins have twenty different monomers; • 2HNCH(R)CO2H
2) Each monomer in both nylon and proteins has two functional groups. • But in nylon they are the same; either two amines or two acid chlorides; 2HN(CH2)6NH2 ClC(O)-(CH2)4-(O)CCl But in proteins they are different; • 2HNCH(R)CO2H
3) Both nylon and proteins are condensation polymers. • But in nylon HCl is eliminated. 2HN(CH2)6 NHC(O)(CH2)4(O)CCl +HCl • Whereas in proteins it is H2O. • 2HNCH(R)COHNCH(R)CO2H + H2O
Kevlar • Kevlar has two different monomers; • 2HN(C6H4)NH2 • 1,4 diamino benzene • H2OC-C6H4-CO2H • Benzene 1,4 dicarboxylic acid • Giving a repeat; • -[HN(C6H4)6NHC(O)-C6H4-C(O)]-