短支链PP对长支链PP加工流变行为的影响及机理

Effects and Mechanism of Short Chain Branched PP on the Rheology Behavior of Long Chain Branched PP

研究了线型等规聚丙烯(iPP)和短支链聚丙烯(SCBPP)的引入对长支链聚丙烯(LCBPP)加工流变行为的影响。结果表明:将线型iPP引入LCBPP相当于降低了长支链分子在共混体系中的含量;而当SCBPP引入LCBPP时,由于短支链的隔离作用会使LCBPP分子链间距增大,并且阻碍了LCBPP长支链分子间的缠结,而未缠结的长支链则起到类似增塑剂的作用。因此,线型iPP和SCBPP的引入均会使LCBPP的剪切黏度降低,其中在用量相同的条件下,SCBPP对LCBPP剪切黏度的降低效果明显优于线型iPP。

The influence of linear isotactic polypropylene（iPP） and short chain branched polypropylene（SCBPP） on the rheology of long chain branched polypropylene（LCBPP） was studied.The results show that： the iPP decreased the content of long chain branched molecules when iPP was blended with LCBPP.The segregation effect of SCBPP increased the distance between molecules of LCBPP and weakening the entanglement of long chain branched molecules when SCBPP was blended with LCBPP,moreover,non-entangled molecules of LCBPP would act as the plasticizer.All of that decreased the shear viscosity of LCBPP.Under the same blending quantity,the viscosity-reducing effect of SCBPP was much more obvious than that of iPP.