Early Encounters with Condensation Polymers

Lourengo also prepared poly-(ethylene succinate) 

Although this was not an explicit representation of the structure, Lourengo clearly comprehended the complexity of his products. 

Only four years after Kekule proposed the ring structure for benzene, and before the configuration of salicylic acid was established, Kraut concluded on the basis of sound chemical evidence that the products obtained on heating acetylsalicylic acid possess chain structures formed through intermolecular esterification. He assigned the dimeric and tetrameric formulas 

The preparation of polymers in this early phase of synthetic organic chemistry seems not to have been uncommon. It must not be concluded from the above citations, however, that their polymeric nature usually was comprehended. In the vast majority of instances this was not the case. 

Marcker reported in 1862 on the formation of a product in the pyrolysis of salicylide which melted at 103°C and possessed the empirical formula C6H4O. These observations were confirmed by Kraut,and the product was given the name phenylene oxide. Unquestionably it was polymeric but, like numerous other polymers encountered by accident, it has never been investigated as such. 

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