Synthesis of isotactic polypropylene-based block copolymers

以乙二烯双(4，5，6，7-四氢-1-吲基)二氯化锆-甲基铝氧烷为催化剂体系，合成了端亚乙烯基团为数均相对分子质量为5,300，熔点为114ﾟC的等规聚丙烯(PP)。所得聚合物在甲苯中用硼烷-二甲基硫醚处理，然后与正戊烷-1，5-二(溴化镁)反应得到溴化镁封端的等规聚PP，聚合物与碘接触得到链末端含碘的等规聚PP，产率约85%。在-78ﾟC下，以溴化镁为引发剂，进行甲基丙烯酸甲酯的聚合反应，合成了等规聚PP-嵌段-聚甲基丙烯酸甲酯。为了将该方法应用于合成A-B-A型嵌段共聚物，尝试合成了α，omega-二乙烯基PP。我们曾报道，在TiCl3-AlEt2Cl-ZNET2催化剂下得到的PP的锌聚合物键是…的通过与烯丙基溴的偶联反应，以较高的产率将更多的n转化为乙烯基。因此，我们合成了双(3-丁烯基)锌(BBZ)和双(7-辛烯基)锌(BOZ)作为助催化剂和/或链转移剂与TiCl3结合，得到熔点在160ﾟC左右的等规聚丙烯。双(烯基)锌化合物作为链转移剂合成了低相对分子质量的端锌聚合物。但没有观察到3-丁烯基，这可能是由于咬背环化所致。此外，BOZ还可以与丙烯发生共聚反应，得到侧链上含锌碳键的PP。通过与烯丙基溴偶联，将末端的锌碳键和侧链转化为乙烯基，得到具有少量8-壬烯基的α，omega-二乙烯基PP作为侧链，现在正在用上述方法从α，omega-二乙烯基PP合成嵌段共聚物。较少

Isotactic poly (propene) (PP) having a terminal vinylidene group (number average molecular weight=5,300, melting point=114ﾟC) was prepared with the ethylenebis (4,5,6,7-tetrahydro-1-indenyl) zirconium dichloride-methylaluminoxane catalyst system. The polymer produced was treated with borane-dimethylsulfide in toluene, followed by reacting with pentane-1,5-di (magnesium bromide) to obtain magnesium bromide (MgBr) -terminated isotactic PP.The polymer was brought into contact with iodine to give isotactic PP having an iodine group at the chain end in about a 85% yield. Polymerization of methyl methacrylate was then conducted at -78ﾟC using the MgBr-terminated PP as an initiator to synthesize isotactic PP-block-poly (methyl methacrylate) copolymer.In order to apply this method to the synthesis of A-B-A type block copolymers, an attempt was made to prepare alpha, omega-divinyl PP.We have previously reported that the Zn-polymer bonds of PP obtained with the TiCl_3-AlEt_2Cl-ZnEt_2 catalyst ca … More n be converted to vinyl groups in fairly good yield by the coupling reaction with allyl bromide. Therefore, bis (3-butenyl) zinc (BBZ) and bis (7-octenyl) zinc (BOZ) were synthesized and used as cocatalyst and/or chain transfer reagent combined with TiCl_3. These catalyst systems gave isotactic poly (propene), of which melting points were around 160ﾟC.The bis (alkenyl) zinc compounds acted as a chain transfer reagent to give zinc-terminated polymers with low molecular weight.IR,^1H NMR and ^<13>C NMR analyzes of the produced polymers indicated the incorporation of 7-octenyl group at the initiation chain end. However, 3-butenyl group was not observed, which may be probably due to back-biting cyclization. In addition, BOZ could copolymerize with propene to give PP which had Zn-carbon bonds in side chains. The zinc-carbon bond at the termination end and the side chains were converted to vinyl groups by coupling with allyl bromide to obtain alpha, omega-divinyl PP having a small amount of 8-nonenyl groups as side chain.Synthesis of block copolymers from the alpha, omega-divinyl PP by the method described above are now being carried out. Less