Triflic acid and P₄-t-Bu superbase both catalyze the ring-opening polymerization (ROP) of 2,2,4,4,6,6-hexamethyl-8,8-diphenylcyclotetrasiloxane (I) to yield a mixture of linear copoly(dimethylsiloxane/diphenylsiloxane) (3:1 mole ratio), low molecular weight oligomer and cyclic siloxanes. The molecular weight distribution, microstructure and thermal properties of the copolymers have been determined. The composition of the low molecular weight fractions have been analyzed. Triflic acid catalyzed ROP of I yields a copolymer whose microstructure can be accounted for by chemoselective ring opening of a single silyloxonium ion intermediate. In addition, 40% of I is recovered. On the other hand, P₄-t-Bu superbase catalyzed ROP of I yields a copolymer whose microstructure is random. The low molecular weight fraction, in this case, is made up of oligomer and a number of cyclotetra-, cyclopenta- and cyclohexasiloxanes.

中文翻译：

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酸和碱催化的2,2,4,4,6,6-六甲基-8,8-二苯基环四硅氧烷的开环聚合

三氟甲磺酸和P ₄ -吨-Bu超强碱既催化开环聚合2,2,4,4,6,6-六甲基-8,8-二diphenylcyclotetrasiloxane的（ROP）（我），得到线性共聚的混合物（二甲基硅氧烷/二苯基硅氧烷）（3∶1的摩尔比），低分子量低聚物和环状硅氧烷。已经确定了共聚物的分子量分布，微结构和热性能。低分子量级分的组成已被分析。三氟甲磺酸催化的I的ROP产生了一种共聚物，其微观结构可以通过单个甲硅烷基氧离子中间体的化学选择性开环来解释。另外，I的40％被回收。另一方面，P ₄-吨-Bu超强碱催化ROP的我产生了共聚物，其显微组织是随机的。在这种情况下，低分子量部分由低聚物和许多环四，环戊和环六硅氧烷组成。