β Scribed by K. Ueberretter; V.-H. Karl; A. Altmeyer
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Heats of fusion of polyethylene-adipate, pimelate, suberate and azelaate have been determined by two methods, viz. DTA and the pressure dependence of the melting point up to 6000 bar. Degrees of crystallization were measured dilatometrically. Entropies of fusion were divided into volume and conformational entropy terms, only the latter alternates. Alternation of melting points depends on enthalpy of fusion AH=, entropy of fusion ASm and volume change Av on melting; influence of the functions increases thus AV,. < AH,. < ASm and ASm is dominant. Entropy and heat of fusion alternation is explained by the conformational change on melting governed by the driving force of maximum H-bridge formation.
π SIMILAR VOLUMES
A~traet--The results obtained in a study of the heat and entropy of fusion, and a few data on the crystallization kinetics, of poly-/3-propiolactone and poly-@caprolactone are reported. Attention is focused on the entropy data for the two polymers. A comparative, theoretical analysis of the constant
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