Study of thermoelastic properties of ethylene-vinyl acetate copolymer

Abstract

The thermoelastic properties of the random ethylene-vinyl acetate copolymer crosslinked with dicumyl peroxide were investigated. It was found that the relationships between equilibrium stress and temperature showed a discontinuity in the temperature range 38–42°C which was due to the crystalline character of the samples. The value of energetic contribution fu/ f is negative at elongations ranging from 1.1 to 2.1 while it assumes a relatively high value at greater elongations. The values of relative energetic contribution fu/ f change with elongation and are in agreement with the values of fu/ f calculated from shear modulus for the region of medium elongations in the investigated range. The character of the relationship between f u or fu/ f and elongation indicates that a change in the intra- and inter-molecular interaction energies occurs in the case of uniaxial strain of the investigated copolymer.