Influence of tensile deformation on the crystalline organization of ethylene copolymers

The influence of tensile deformation on the crystalline properties of ethyl ene copolymers (ethylene-vinyl acetate [EVA] copolymers) was investigated b y differential scanning calorimetry (DSC). The consequence of drawing on th e mobility of the amorphous phase also was investigated through the study o f the glass transition temperature. The results indicate that more disorgan ized crystals, melting at a lower temperature, are present after the tensil e deformation, reducing the mobility of the amorphous chains, as shown by a n increase of the glass transition temperature. For the lowest molecular we ight copolymer, less crystal line changes are observed after the tensile te st, probably due to the fact that no stiffening appears during the drawing.