Synthesis of isotactic polypropylene-based block copolymers

以二氯乙烯（4,5,6,7-四氢-1-茚二基）锆-甲基铝氧烷为催化剂体系制备了端为偏乙烯基的等规聚丙烯（PP）（平均分子量为5,300，熔点为114 C）。用溴二甲基硫化物在甲苯中处理聚合物，然后与戊烷-1,5-二（溴化镁）反应得到端部溴化镁（MgBr）的等规PP，再与碘接触得到链端有碘基团的等规PP，产率约为85%。然后，以端接mbr的PP为引发剂，在-78℃的温度下聚合甲基丙烯酸甲酯，合成了等规PP-嵌段聚甲基丙烯酸甲酯共聚物。为了将此方法应用于A-B-A型嵌段共聚物的合成，我们尝试制备α， ω -二乙烯基PP。以前有报道称，用TiCl_3-AlEt_2Cl-ZnEt_2催化剂制备的PP的zn -聚合物键可以与烯丙基溴偶联反应，以较好的收率将更多的n转化为乙烯基。因此，合成了双（3-丁烯基）锌（BBZ）和双（7-辛烯基）锌（BOZ），并与TiCl_3结合作为助催化剂和/或链转移试剂。这些催化剂体系产生了等规聚丙烯，其熔点在160℃左右。双（烯基）锌化合物作为链转移试剂得到低分子量的端锌聚合物。所得聚合物的IR、1H NMR和13>C NMR分析表明，在起始链端加入了7-辛烯基。但没有观察到3-丁烯基，这可能是由于背咬环。此外，BOZ还能与丙烯共聚得到侧链上有锌碳键的PP。末端的锌碳键和侧链通过与烯丙基溴偶联转化为乙烯基，得到具有少量8-壬烯基为侧链的α， ω -二乙烯基PP。用上述方法从α， ω -二乙烯基PP合成嵌段共聚物。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