极性单体是指带有极性基团的烯烃类单体,主要包括含卤素类极性单体、含氧类极性单体、含氮类极性单体和含磷类极性单体。其中带有乙烯基且与所带极性基团相共轭的极性单体称为极性乙烯基单体,如甲基丙烯酸甲酯、2-乙烯基吡啶和乙烯基磷酸酯等。这类单体所形成的极性乙烯基聚合物是极性基团作为侧链的烯烃聚合物,该类化合物在黏性、韧性、界面性质(染色性和印刷性)、与溶剂或其他聚合物的相容性方面较传统非极性聚烯烃材料有明显的优势。为了使聚合物具有好的物理性能,获得具有一定规整度的聚合物是近年来研究的热点。聚合物的立体结构对其本身的物理性能有着显著的影响,如熔点、玻璃化转变温度和机械性能等。获取立构规整性聚合物的最有效方式是发展催化聚合反应的立体选择性催化剂。本文综述了近几年极性乙烯基单体立体选择性聚合催化剂的研究进展,这里所涉及的极性乙烯基单体包括:丙烯酸酯类、丙烯酸酰胺、乙烯基磷酸酯、乙烯基吡啶和杂原子取代苯乙烯单体。所涉及的聚合体系是配位聚合、路易斯酸碱对和阴离子聚合体系。
The polar monomer is an olefin monomer with polar group. It includes polar monomer with halogen, polar monomer with oxygen atom, polar monomer with nitrogen atom, and polar monomer with phosphorus atom. The polar vinyl monomer is monomer with conjugated vinyl group and polar group. The polymerization of polar vinyl monomer produces a polymer with polar group. This polymer has obvious advantages over the traditional non-polar polyolefin materials in terms of viscosity, toughness, interfacial properties (dyeing and printing), and compatibility with solvents or other polymers. In order to obtain polymer with good physical properties, it is a hot spot to get a polymer with certain degree of regularity. The structure of the polymer has a significant impact on its physical properties, such as melting point, glass transition temperature and mechanical properties. The most effective way to obtain the stereoregular polymer is the development of the stereoselective catalysts for polar vinyl polymeization. This paper reviews the recent research progress in stereoselective catalysts for the polar vinyl monomer polymerization, the polar vinyl monomers involved include: methacrylate, methacrylamide, vinylphosphonate, vinyl pyridine, 2-isopropenyl-2-oxazoline and heteo-atom substituted styrene. The polymerization system includes the coordination polymerization, the Lewis pair, and the anionic polymerization system.