Linear aliphatic chains, motion

The Hammett equation also fails for open-chain aliphatic derivatives. For example, there is no simple linear relationship between log K for a scries of substituted ethanoic acids (RCH2C02H) and log k for the hydrolysis rates of similarly substituted ethyl ethanoates (RCH2C02C2H5). The freedom of motion available to a flexible open-chain compound permits a much wider range of variations in steric effects than for meta- and para-substituted aromatic compounds. 

The polymers considered in Sects. 4 to 6, i.e. polyethylene fere-phthalalc), bisphenol A polycarbonate and aryl-aliphatic polyamides, are linear polymers or copolymers without side chains, in which molecular motions occur in the glassy state. Detailed analysis of the transitions, mostly the ft transition, reveals that several processes are involved in this ft transition and that the co-... 

The discussion of the behavior of eondis crystals of flexibte linear macromolecules and some of the homolc ous oUgcaners covers a witte range of cdisorder-effects and accompanying motion. For many of the macromolecules in the eondis phase chain-extension afto- erystallization with chain folding is possible [polyethylene, polytetrafluOToethylene, poly(vinylidene fluoride), polydilorotrifluoro-ethylene, some aliphatic nylons and polyphosphazenes]. Stx h extended ehain crystals are exceptionally stable and elose to equlibrium. 

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