Benzene dicarboxylates , aromatic polymers

One super fiber is Kevlar, an aromatic polyamide. It is a polymer of 1,4-benzene-dicarboxylic acid and 1,4-diaminobenzene. Aromatic polyamides are called aramides. 

Aramids are formed through step growth polymerization of aromatic diacid chlorides with aromatic diamines in a polar aprotic solvent such as N, -dimethylformamide pMF) to a DP of 100-250. The meta- and para-substi-tuted benzene dicarboxylic acid chlorides and diamines are characteristically used for aramid fibers presently in production, but other fully aromatic ring systems are possible future sources of aramid polymers for fi bers ... 

The most familiar condensation polymers arepolyamides.polyesters, andpolycarbonates. Tlie aramids, polyamides in which aromatic rings are joined by amide bonds, are one class of condensation polymer. Heating 1,4-benzenediamine and the acyl chloride of benzene-1,4-dicarboxylic acid (terephthalic acid) gives the aramid Kevlar with loss of hydrogen chloride. 

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