半连续乳液聚合法制备高支化聚甲基丙烯酸甲酯

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。

Hyperbranched PMMA prepared by semi-continuous emulsion polymerization

With methyl methacrylate(MMA) as monomer,divinylbenzene(DVB) as branching agent,dodecanethiol(C12SH) as chain transfer agent,a series of PMMA(polymethyl methacrylate) with lower agglomeration ratio and higher DB(degree of branching) were prepared by semi-continuous emulsion polymerization.The influences of different monomer ratios on some emulsion properties such as stability,DB,glass transition temperature(Tg),molecular weight and its distribution were emphatically discussed.The results showed that the hyperbranched PMMA emulsion had smaller particle size and narrower particle size distribution.The DB was larger and larger,and the molecular weight of polymer and Tg were lower and lower,and the molecular weight distribution was narrower and narrower with increasing total contents between DVB and C12SH when molar ratio of n(DVB)∶n(C12SH) was 1∶2 or with increasing contents of C12SH when molar ratio of n(MMA)∶n(DVB) was 100∶10.