The crude low isotactic polypropylene (LIPP) was fractionated by subsequent extractions with boiling ethyl ether, n - hexane, and n - heptane.

• 用溶剂分级法对低等规聚丙烯(LIPP)进行了分级,测定了各级分的含量、分子量及其分布、特性粘数、分子链规整度及序列分布等分子性质。