聚丙烯分子量及分子量分布的化学和机械降解的影响

本文研究了化学和机械降解对聚丙烯分子量和分子量分布的影响。原始聚丙烯树脂的分子量,分子量分布与聚合过程中氢调量、催化剂类型有密切的关系。随着氢调量增加,原始树脂的分子量变小、分子量分布变宽。但是,由原始聚丙烯树脂降解的产物在熔体流动指数(MFI)相同的条件下,氢调量多则降解树脂的分子量大、分子量分布宽,从高效催化聚丙烯得到的降解树脂的分子量、分子量分布都明显低于用普通催化剂产生的降解树脂。通过调节聚合过程中的氢调量、催化剂及聚合后的化学降解程度,可以在较大的范围内选择适合于纺制优质聚丙烯纤维的分子量和分子量分布。

EFFECTS OF CHEMICAL AND MECHANICAL DEGRADATION ON MOLECULAR WEIGHT AND ITS DISTRIBUTION OF POLYPROPYLENE

The effects of chemical and mechanical degradation on molecular weight(MW) and its distribution (MWD) of polypropylene are studied, MW and MWD of degraded PP resin are closely related to the original PP resin, with increasing amount of hydrogen during polymerization of original PP, the MW and width of MWD of degraded PP resin increase under the same melt flow index (MFI). The degraded PP resin obtained from high effecience catalyst show much lower MW and narrower MWD than that from ordinary catalyst, by choosing the suitable catalyst, amount of hydrogen during polymerization and degree of chemical degradation it is possible to produce PP resin for improving fiber spinning process.