八甲基环四硅氧烷的乳液离子开环聚合反应

Emulsion Ionic Ring-Opening Polymerization of Octamethyltetracyclosiloxane

采用乳液离子开环聚合手段制备了聚有机硅氧烷乳液。考察了聚合过程中乳化剂和催化剂的种类、用量对八甲基环四硅氧烷(D4)的转化率及聚合过程中粒子大小变化的影响,并用气相色谱、气相色谱-质谱联用手段分析了聚合过程中单体及副产物含量的变化情况。实验结果表明,当使用非离子型乳化剂时,D4不能开环聚合;而当使用离子型乳化剂时,可有效实现开环聚合;不同类型的乳化剂和催化剂呈现不同的聚合特点;在D4的阴、阳离子催化开环聚合过程中,均发生back-biting现象,但后者更为显著。

Polysiloxane emulsions were prepared through emulsion ionic ring-opening polymerization. The influence of the kind and amount of surfactant and catalyst was studied by monitoring the evolution of monomer conversion and particle size, and the evolutions of monomer and side products concentration were analyzed by gas chromatograph and gas chromatograph-mass spectrometer. The results show that polysiloxanecan be effectively produced in anionic and cationic surfactant system while D4 can not be polymerized in non-ionic surfactant system. Polymerization is affected significantly by the kind and amount of surfactant and catalyst. It is also found that there has back-biting phenomenon in emulsion ionic ring-opening polymerization, especially in cationic catalyst cases.