摘要
基于一种功能性Ziegler-Natta催化体系,利用工业丙烯环管聚合工艺,制备了具有β-定向结晶特性的聚丙烯均聚物树脂。这种功能性Ziegler-Natta催化体系的活性与立体定向能力均与目前工业的聚丙烯催化剂基本相当,所得聚合物亦具有良好的颗粒形态。通过调节聚合参数,获得熔体流动指数(10 min)分别为0.42,2.80 g的两个β-定向结晶聚丙烯均聚物树脂试样。WAXD和DSC测试结果表明,聚合得到的粉末试样主要呈现出α结晶特征峰,但经熔融再结晶后,β结晶特征峰明显显现,β结晶含量可达80%左右,且不受试样反复升降温的影响。聚合物中除含有少量较小尺寸的α球晶外,β-定向结晶聚丙烯均聚物树脂主要表现出β晶特有的球晶形貌。力学性能测试结果表明,这种β-定向结晶聚丙烯均聚物树脂具有优异的室温抗冲性能。
β-Crystalline-specified polypropylene（PP） homopolymer resins were synthesized with a novel functional Ziegler-Natta catalyst system in an industrial loop reactor. The functional Ziegler- Natta catalyst exhibited high activity and stereospecificity compared to commercial PP catalysts. The homopolymers showed good particle morphology. Two β-crystalline-specified PP resins with melting indexes（10 min） of 0.42 and 2.80 g were prepared by controlling polymerization parameters. The results of WAXD and DSC revealed that although α-crystallites were the main crystalline structure in the PP powder samples, β-crystallites dominated the crystalline type with approximate content of 80% after a melting-crystallization procedure; this structure was proved to be stable in repeated cooling-heating cycles. The β-crystalline-specified PP resins indicated β-spherocrystal morphology in addition to small amount of α-spherocrystal after crystallization. Mechanical experiments showed that the β-crystallinespecified PP resins had excellent impact-resistance at ambient temperature.
出处
《石油化工》
CAS
CSCD
北大核心
2014年第5期491-497,共7页
Petrochemical Technology
