钼系催化体系制备高乙烯基含量丁苯共聚物的研究

以磷酸三丁酯(TBP)为配体改性的五氯化钼(MoCl5)为主催化剂、二丁基镁[Mg(Bu)2]为助催化剂组成二元催化体系,在丁二烯(Bd)物质的量浓度为2.6×103 mol·L-1和Bd/苯乙烯(St)质量比为3的条件下进行丁苯共聚物的配位聚合,研究催化体系和聚合条件对聚合反应的影响,并采用凝胶渗透色谱、傅里叶变换红外光谱、核磁共振氢谱、差示扫描量热法等对共聚物的微观结构进行分析。试验得出的最佳反应条件为:TBP/MoCl5物质的量比2,MoCl5/单体物质的量比1×10-3,Mg(Bu)2/MoCl5物质的量比3,聚合温度70℃,聚合时间12 h。在该条件下,Bd和St聚合活性较高,共聚物的数均相对分子质量为1.24×105,相对分子质量分布较宽,Bd单元中1,2-结构物质的量分数大于0.85,聚合产物为高乙烯基含量无规丁苯共聚物。

Study on Preparation of Bd-St Copolymer with High Vinyl Content by Molybdenum Catalytic System

The coordination polymerization of butadiene(Bd)and styrene(St)was carried out with binary molybdenum catalytic system which consisted of the main catalyst of molybdenum pentachloride(MoCl5)modified by tributyl phosphate(TBP)ligands and co-catalyst dibutyl magnesium[Mg(Bu)2]under the condition that the mole concentration of Bd was 2.6×103 mol·mL-1 and the mass ratio of Bd/St was 3.The effects of the catalytic system and polymerization conditions on the polymerization reaction were investigated,and the microstructure of the copolymer was analyzed by GPC,FTIR,1 H MNR and DSC.The results showed that,the optimum reaction conditions were as follows:the mole ratio of TBP/MoCl5 was 2,the mole ratio of MoCl5/monomer was 1×10-3,the mole ratio of Mg(Bu)2/MoCl5 was 3,the polymerization temperature was 70℃,and the polymerization time was 12 h.Under these conditions,the copolymerization activity of Bd and St was relatively high,the number average molecular weight of the copolymer was up to 1.24×105,the relative molecular weight distribution was wide,and Bd unit was mainly 1,2-structure with mole fraction over 0.85.The polymerization product was random Bd-St copolymer with high vinyl content.