エチレン-スチレン共重合体の機械的練込みによる高次構造の変化と絶縁破壊特性

抄録

Relation between morphological change, induced by copolymerized benzene rings or by kneading, and the dielectric strength of ethylene-styrene copolymer was studied. In unkneaded samples, the lamellar thickness decreases and the lattice constant along the a-axis increases with increasing styrene content. However, in kneaded samples, the lamellar thickness and the lattice constant remain constant up to the styrene content of 3.10wt%. Spherulite is observed with a polarizing microscope in unkneaded samples, but it disappears in kneaded samples. Kneaded samples, especially the kneaded sample with the styrene content of 3.10wt%, have higher breakdown strength than unkneaded samples. Styrene content of the sample showing the highest breakdown strength increases as the temperature decreases. At -50°C or -80°C the sample with the styrene content of 15.40wt% has the highest breakdown strength of all the samples. It is considered that benzene rings are moved to the interfacial region between lamellar and amorphous parts by kneading and hinder the acceleration of electrons along the lamellar. This effect of benzene rings becomes pronounced in low temperature region as the breakdown process is electronic.