The crystalline fl-form of ethylene/propylene random and block copolymers was obtained by crystallizing in the presence of a two-component fl-nucleator. The influence of converting the crystalline copolymers from the c~-form to the fl-form on the drawing behaviour and impact strength was studied. The results show that the fl-phase copolymer has higher impact strength, slightly lower yield strength and a higher degree of stress whitening than the ~-phase copolymer. A stretching-induced or impact-induced fl-~ transformation in parallel with micro-crazing was also noticed
Посилання на статтю:
Effect of converting the crystalline form from to/Y on the mechanical properties of ethylene/propylene random and block copolymers / Xiaodong Zhang and Guanyi Shi // Polymer. – 1994. – Vol 35. – P. 5067-5072.