Condensation Polymers

Polyamides and polyesters are two very important classes of synthetic polymers. Production of each type involves chemistry discussed in this chapter.

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Hexane-1,6-dioyl chloride reacts with 1,6-hexanediamine to form initially an amide, then sequentially many amides. This results in nylon 6,6.

nylon.mol

PET.gif (4414 bytes) Ethanediol reacts with dimethyl terephthalate (dimethyl benzene-1,4-dioic acid) to form ester linkages, and eventually a long chain of polyethylene terephthalate (PET)

pet.mol

Each of these involves the loss of a small molecule (HCl in the case of nylon; MeOH in the case of PET), thus they are called "condensation" polymers. Cyclic molecules may be polymerized in a fashion that does not result in expulsion of a small molecule; an example is Nylon 6, made from caprolactam:

nylon6.gif (5257 bytes) A 7-member ring lactam can be polymerized by base to give Nylon 6.

nylon6.mol