抗冲聚丙烯管材专用树脂的结构与性能

研究了乙丙嵌段共聚聚丙烯(PP-B)管材专用树脂的结构与性能。PP-B具有典型的乙丙嵌段共聚物序列结构,是含有丙烯均聚物(PP-H)、乙丙橡胶(EPR)及可结晶乙丙共聚物的抗冲聚丙烯(PP)；其中,均聚物与共聚物比例合理,形成的EPR多、粒径小,对提高冲击强度有利。提高PP-H的质量分数和等规指数,可有效提高PP- B的刚性。PP-B的熔点与PP-H近似；相对分子质量分布较宽,流变性能好；微观与亚微观结构合理,宏观性能优良。

Structure and properties of the specialty PP for tubing

This paper studied the structure and properties of propylene-ethylene block copolymer(PP-B)as speciality resin for tubing.The PP-B copolymer possessed a typical block sequential structure and comprised segments of propylene homopolymer,ethylene-propylene rubber and crystallizable ethylene-propylene copolymer as impact polypropylene.The proportion between homopolymer and copolymer was reasonable.In the sequential structure,the proportions of propylene,ethylene and propylene-ethylene-propylene chain segments were rather high.The ethylene-propylene rubber in great amount and in smaller particle size was beneficial to increasing the impact strength.The rigidity of PP-B could be raised effectively by increasing mass fraction and isotactic index of propylene homopolymer.The melt point of the PP-B copolymer was similar to that of propylene homopolymer.In addition,the PP-B copolymer featured a wide relative molecular mass,good rheology,rational microstructure and sub-microstructure and eminent macro-performance.