轧制聚丙烯取向结构及分布的表征

CHARACTERIZATION OF THE ORIENTATION STRUCTURE AND DISTRIBUTION IN ROLLED POLYPROPYLENE

用偏光显微镜、扫描电镜及广角 X射线衍射法对轧制聚丙烯的取向结构进行了研究 ,其球晶结构轧制后成为一种“饼”状 ,并沿轧制方向排列。用 X射线极角扫描法 (透射 )可以得到聚合物结晶的 c轴取向分布。Legendre多项式中的偶数项系数〈Pn(cosχ)〉c描述了聚合物分子链的取向分布 ,以近仿射形变理论计算出〈Pn〉c(n从 2至 1 0 ) ,其结果与实验数据有较好吻合。

The polymer orientation structure in rolled polypropylene sheets was studied by DSC, SEM and WAXD. The DSC rusults show that the crystallinity of polymer increased with the rolling reduction ratio. The study of fracture surface according to the photos of SEM displays that the initial isotropic structrue is displaced by layer or fibril at high deformation. Even order 〈 P n(cos χ )〉 c coefficients of the Legendre polynomial series for n form 2 to 10 describing the c axis or orientation distribution of the molecular chains were determined from measurements of polar angle scan with transmission technique. The 〈 P n〉 c for n from 2 to 10 curves calculated from the psuedo affine defromation theory are in good agreement with the experimental data.