Abstract
Abstract From the study of the viscosity of aliphatic long-chain polyesters over a wide range of temperatures, the following results have been obtained : (1) Among aliphatic long-chain polyesters with ether bonds in the main chains, several crystalline polyesters have been obtained. (2) Accordingly, it has been possible to compare the temperature dependence of the viscosity of the amorphous and the crystalline polyesters with similar chemical structures. (3) When the temperature is raised, every apparent activation energy for viscous flow (E\eweq) approaches a fixed value, independently of the chemical structure of the polyester. (4) However, the viscous flow state of the amorphous polyester changes discontinuously in connection with the chemical structure near the melting point of the corresponding crystalline polyester. (5) In the “transition area” for viscous flow, the viscosity and the apparent activation energy (E\eweq) are, respectively, about 10 poises and 11 kcal./mol.
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