颗粒内受限聚合法制备PP/POE/PS合金

摘要

Polypropylene/ethylene octene copolymer/polystyrene ( PP/POE/PS) ternary alloys were prepared via diffusion and subsequent polymerization of styrene ( St) in PP/POE alloy granules. St could diffuse into the center of the PP/POE alloy granules and PS phases mostly included in POE phases with a particle size from several tens of nanometers to several hundred nanometers. The size of PS particles was influenced by the amount of styrene adsorbed and the size of the POE phases. The PS particles in POE phases formed in the center of the granules were the smallest. The diffusion and polymerization process of St in PP/POE ( mass ratio, 80: 20) was studied. The diffusion rate and the maximum adsorption of styrene in PP/POE were larger than those in pure PP as existence of amorphous POE phase was beneficial for diffusion of monomer. The content of PS in PP/POE/PS alloys can be tailored by changing the amount of monomer. Incorporation of PS into POE domains made the POE domains bigger and then resulted in lower melting temperatures and crystalline temperatures of PP, and PS dispersed in PP/POE/PS with a high PS content acted as a nucleation agent of PP.%以等规聚丙烯/乙烯-辛烯共聚物(PP/POE)合金颗粒为扩散基体,苯乙烯(St)为扩散单体,利用颗粒内受限聚合法制备了PP/POE/PS三元合金.结果表明,对于POE质量分数为20％～40％的PP/POE合金颗粒,St均可扩散至直径为4 mm的颗粒中心部位,在POE非晶相中生成相尺寸为几十至几百纳米的PS球.在PP/POE合金颗粒的不同部位,因POE相尺寸及单体的吸附量不同,生成的PS相尺寸也不同,在颗粒中心部位生成的PS球最小.研究了St在PP/POE(质量比80∶20)颗粒中的扩散-聚合行为,结果表明,St在合金颗粒中的扩散速率和扩散饱和值远大于在纯PP颗粒中的扩散速率和饱和值,这主要是因为PP/POE合金颗粒中的非晶POE相有利于扩散.改变单体投料量可以获得具有不同PS含量的PP/POE/PS三元合金.结晶性能研究结果表明,PS在非晶POE相中的优先分布会使POE相体积增大,从而使PP的结晶温度和熔融温度降低.随着PS量的进一步增大,分布在PP中的PS对PP有结晶成核作用.