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以甲基丙烯酸甲酯(MMA)为单体、二乙烯基苯(DVB)为支化剂和十二硫醇(C12SH)为链转移剂,采用半连续乳液聚合法制备了一系列低凝聚率高支化的PMMA(聚甲基丙烯酸甲酯)。着重探讨了不同单体配比对该乳液的稳定性、支化度(DB)、玻璃化转变温度(Tg)、相对分子质量及其分布等影响。结果表明:高支化PMMA乳液的粒径较小、粒径分布较窄;当n(DVB):n(C12SH)=1:2时,DVB和C12SH总用量越多[或当n(MMA):n(DVB)=100:10时,C12SH用量越多],聚合物的DB越高、相对分子质量越小、相对分子质量分布越窄且Tg越低。
A series of low coacervation rates were prepared by semi-continuous emulsion polymerization using methyl methacrylate (MMA) as monomer, divinylbenzene (DVB) as branching agent and dodecanethiol (C12SH) as chain transfer agent Hyperbranched PMMA (Polymethylmethacrylate). The effects of different monomer ratios on the stability, branching degree (DB), glass transition temperature (Tg), relative molecular mass and their distribution of the emulsion were discussed emphatically. The results showed that the particle size of the hyperbranched PMMA emulsion was small and the particle size distribution was narrow. When n (DVB): n (C12SH) = 1: 2, the total amount of DVB and C12SH was more [ : n (DVB) = 100: 10, the more C12SH is used], the higher the DB of the polymer, the smaller the relative molecular mass, the narrower the relative molecular mass distribution and the lower the Tg.