以十二烷基磺酸钠(SDS)为乳化剂,将2种茂金属化合物CpTiCl3和CpZrCl3·DME成功应用于甲基丙烯酸甲酯(MMA)和苯乙烯(S)水相均聚及共聚合反应中,以^1H-NMR和GPC表征了聚合物.详细考察了时间和温度对聚合反应的影响.在聚合反应温度为55 ℃、反应时间为15 h、用水量为10 mL以及 CpTiCl3和单体的物质的量比为1∶100的条件下,甲基丙烯酸甲酯(MMA)聚合转化率高达92%,聚甲基丙烯酸甲酯(PMMA)和聚苯乙烯(PS)的重均相对分子质量分别为7.78×10^5和10.50×10^5,相对分子质量分布分别为4.39和3.35,PMMA的间同摩尔分数为56%.当投料比(即苯乙烯和MMA的物质的量比)为1∶1,而其他条件不变时,所得共聚物的重均相对分子质量为15.00×10^5,相对分子质量分布为3.45.在聚合反应温度为55 ℃、反应时间为15 h、用水量为20 mL以及CpZrCl3·DME和单体的物质的量比为1∶100的条件下,PMMA和PS的重均相对分子质量分别为15.00×10^5和4.27×10^5,相对分子质量分布分别为3.50和5.85.
Two metallocene complexes, CpTiCl3 and CpZrCl3·DME, were successfully used to initiate the homo- and co-polymerization of methyl methacrylate (MMA) and styrene (S) with an anionic surfactant, sodium n-dodecyl sulfate (SDS), in aqueous medium. All polymers were characterized by hydrogen nuclear magnetic resonance spectrometry (^1H-NMR) and gel-permeation chromatography (GPC). Influences of reaction parameters, such as temperature and time, were studied in detail. When the temperature was 55 ℃, the reaction lasted 15 h, the mole ratio of CpTiCl3 to MMA was 1 : 100, and the volume of water consumed was 10 mL, the conversion of MMA was as high as 92%, the syndiotactic mole fraction of PMMA was 56%, and both poly (methyl methacrylate) (PMMA) and poly (styrene) (PS) had large molecular weight and broad molecular weight distribution (MWD) (PMMA: Mw = 7.78×10^5, MWD= 4.39; PS: Mw= 10.50×10^5, MWD=3.35). The copolymerization was carried out at the same condition above with the mole ratio of MMA to styrene being 1 to produce copolymer with Mw being 15.00×10^5 and MWD being 3.45. When the temperature was 55 ℃, the reaction lasted 15 h,the mole ratio of CpZrCl3·DME to monomer was 1 : 100,and the volume of water consumed was 20 mL, the polymerization catalyzed by CpZrCl·DME was as effective as that catalyzed by CpTiCl3 to produce PMMA and PS with large molecular weight and broad molecular weight distribution (PMMA: Mw = 15. 00×10^5, MWD=3. 50; PS: Mw = 4.27×10^5,MWD=5.85).