无规共聚聚丙烯PPR管材专用料结构与性能研究

采用13C NMR、升温淋洗分级(TREF)、差热扫描量热法(DSC)、凝胶渗透色谱(GPC)等分析技术对无规共聚聚丙烯(PPR)管材专用料的结构与性能进行研究。结果表明,PPR管材专用料具有典型的无规共聚物序列结构,PPE和PEP含量高;乙烯较均匀地分布在共聚物链上,乙烯含量低的共聚物相对分子质量大,相对分子质量分布宽;结晶形态发生变化,形成α晶与γ晶的混合晶型,使聚合物的结晶度、结晶温度、结晶速率和熔点均降低。

Study on Structure and Properties of Ethylene - Propylene Random Copolymer Special for Pipes

Structure and properties of ethylene - propylene random copolymer was studied by 13 C NMR, TREF,DSC and GPC. PPR was a specialty resin for pipes,had random copolymer sequence structure, whose PPE and PEP content were high. Ethylene distributed evenly in copolymer chains. Copolymers with low ethylene content have relatively high relative molecular mass while copolymers with high ethylene content have lower relative molecular mass. Besides,relative molecular mass distribution was broad. Crystal defects formed owing to even entrance of ethylene into the molecule chain of the random copolymer. Crystalline form of copolymer changed into a blending of a and y crystals. Consequently, crystal dimension, crystallinity, crystallization temperature and velocity and melting point decreased. PPR' s sequence configuration, together with above mentioned distinguishable features of crystalline form determined its outstanding performance as piping material.