Phenyl‐rich silicone polymers are used for their excellent thermal properties and high refractive indices. Traditional syntheses of these polymers utilize cationic or anionic equilibration, which limits the molecular weights that can be achieved due, in part, to the coproduction of cyclic monomers that must be removed. Kinetically controlled processes may reduce the impact of these limitations, but require high temperatures, alkyllithium initiators and an inert atmosphere; precise structures are difficult to access. The Piers‐Rubinsztajn reaction, combined with hydrolysis, allows the synthesis of highly ordered, Si‐H terminated, phenyl‐rich silicone homo‐ and copolymers comprised of phenylmethyl, diphenyl and, dimethylsilicone monomers. The processes are mild and permit a high level of structural control, including alternating copolymers with different levels of phenyl content (Ph/Si = 0.3–1.5) with molecular weights up to ~100 kDa. Yet higher molecular weights could be achieved—M_n up to 300 kDa—when phenyl‐rich siloxanes were incorporated into block copolymers with dimethylsilicones (Ph/Si = 0.4). Unlike kinetic processes in which cyclic byproducts are formed by redistribution or backbiting (particularly at high conversion), in this process cyclics form near the onset of the reaction and only with low molecular weight starting materials (< 4 siloxane units).

中文翻译：

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从简单的硅烷轻松合成富含苯基的功能性硅氧烷

富含苯基的有机硅聚合物具有出色的热性能和高折射率。这些聚合物的传统合成利用阳离子或阴离子平衡，这限制了可以实现的分子量，这部分是由于必须除去的环状单体的联产。运动控制的方法可以减少这些限制的影响，但是需要高温，烷基锂引发剂和惰性气氛。精确的结构很难访问。Piers-Rubinsztajn反应与水解相结合，可以合成高度有序，Si-H端基，富含苯基的有机硅均聚物和由苯甲基，二苯基和二甲基硅氧烷单体组成的共聚物。过程温和，可以进行高水平的结构控制，包括具有不同苯基含量（Ph / Si = 0.3–1.5）且分子量高达〜100 kDa的交替共聚物。仍然可以实现更高的分子量当将富含苯基的硅氧烷与二甲基硅氧烷（Ph / Si = 0.4）掺入嵌段共聚物中时，_n可达300 kDa。与动力学过程不同，在动力学过程中，通过重新分布或逆位咬合（特别是在高转化率下）形成了环状副产物，在此过程中，环状反应在反应开始时就形成了，并且仅与低分子量的原料（<4个硅氧烷单元）形成。