低收缩聚丙烯制备原理综述  

Review of Preparation Principles of Low-Shrinkage Polypropylene

作　　者：钱丽 QIAN Li(Sinopec(Beijing)Research Institute of Chemical Industry Co.,Ltd.,Beijing 100013,China)

机构地区：[1]中石化(北京)化工研究院有限公司,北京100013

出　　处：《塑料工业》2024年第7期1-8,15,共9页China Plastics Industry

摘　　要：聚丙烯(PP)作为半结晶性通用高分子材料,其制品通常具有较高的成型收缩率。随着精密注塑成型和制件大尺寸的发展,工业界对低收缩聚丙烯的需求也与日俱增。从物理因素上分类,PP的收缩率受到结晶和分子链取向的影响。结晶收缩与PP的结晶度呈正比,分子链取向引起的收缩与内应力以及体系取向程度成正比。低收缩PP的制备方法可总结为PP基体树脂性能调控、无机填料填充改性及烯烃共混改性等。PP基体性能调控原理是通过调控PP的晶型、分子量及分子量分布、共聚单体等,获得低结晶度及低取向体系,从而降低材料收缩率。无机填料填充改性的原理可概括为无机填料的异相成核效应、无机填料形状与分布对PP分子链取向的诱导/阻碍效应及填料填充效应。烯烃共混改性原理可总结为分散相对基体结晶的影响作用与分散相在基体中的形状及分布对PP分子链取向的诱导/阻碍作用。综上,虽然低收缩PP的制备方法各有不同,但原理均为通过调控PP及其作为基体的复合材料的结晶及分子链段的取向,达到阻碍基体结晶,细化球晶及使分子链沿特定方向取向结晶等目的。Polypropylene(PP)is a semi-crystalline general polymer material,and its products usually have a high shrinkage rate.With the developments of precision and large-sized injection molding,the demands for low-shrinkage PP increase rapidly.From a physical perspective,the shrinkage rate of PP is influenced by crystallization and molecular chain orientation.The crystallization shrinkage is directly proportional to the crystallinity of PP,and the shrinkage caused by molecular chain orientation is directly proportional to the internal stress and the degree of system orientation.The preparation methods of low-shrinkage PP could be summarized as the performance control of PP matrix resin,filling modification with inorganic particles,and olefin blending modification.The principle of regulating the performances of PP matrix is to obtain a low-crystallinity and low-orientation system by regulating the crystal form,molecular weight,molecular weight distribution,and copolymer monomers of PP,resulting to reduce the material shrinkage rate.The principle of filling modification with inorganic particles could be summarized as the heterogeneous nucleation effect of inorganic particles,the induction/hindrance effects of the shape and distribution of inorganic particles on the orientation of PP molecular chains,and the filling effect of particles.The principle of olefin blending modification could be summarized as the influences of dispersed phase on matrix crystallization and the inducing/hindering effects of the shape and distribution of dispersed phase in the matrix on the orientation of PP molecular chains.In summary,although the preparation methods of low shrinkage PP vary,the principle is to regulate the crystallization and molecular chain orientation of PP and its composite materials,achieving the goal of hindering matrix crystallization,refining spherical crystals,and directing molecular chains to crystallize in specific directions.

关 键 词：低收缩聚丙烯 聚丙烯结晶 分子链取向 烯烃共混改性 无机填料填充改性 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]