Study of the thermoelastic properties of polymers in open systems: Effect of the used diluent on the energetic ratio f_u/f

Abstract

Effect of diluent on the thermoelastic properties of ethylene-vinyl acetate copolymers was investigated. Dcpendence of the value of ru/f on the thermal coefficient of volume expansion p8, which is a linear function of the thermoelastic point of inversion, was determined. In the case of :I homologous series of diluents values of f,/f were correlated with molar refraction of the diluents used. At determinations of f u / f in the dry state it was found that the values of f,/f are not an additive quantity of the chemical composition of ethylene-vinyl acetate copolymers and that they have maximum values a t the compositions about 50 mole-%. Untersuchung der thermoelastischen Eigenschaften von Polymeren in offenen Systenien: Einflup des Verdunnungsmittels auf das Energieverhultnis fu/fDer EinfluB des Verdunnungsmittels auf die thermoelastisehen Eigcnschaften von Ethylen-Vinylacetat-Copolymeren wurde untersucht. Die Abhangigkeit des Wertcs von f u / f vom thermischen Volumenausdehnungskoeffizienten pa, der eine lineare Funktion des thermoelastisehen Urnkehrpunktes ist, wurde bestimmt. Fur eine homologe Reihe von V A~O and ROMANOV: Study of the thermoelastic properties of polymers in open systems Acta Polymerica 35 (1984) Nr. 9The TSDC-spectra of Kapton-H thermoelectrets in the temperature range 303 to 573 K show three maxima, denoted by j3, a and e, with respective locations around 373, 453 and 553 K and activation energies of 0.14 to 0.34 eV, 0.32 to 0.78 eV and 1.0 to 1.5 eV. These maxima are caused by dipole-orientation, space-charge motion and surface-charge l)