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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Immobilisation of homogeneous olefin polymerisation catalysts. Factors influencing activity and stability
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Immobilisation of homogeneous olefin polymerisation catalysts. Factors influencing activity and stability

机译：均相烯烃聚合催化剂的固定化。影响活性和稳定性的因素

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摘要

The activity and stability of homogeneous olefin polymerisation catalysts, when immobilised on a support, are dependent on both chemical and physical effects. Chemical factors affecting catalyst activity include the ease of formation of the active species, which is strongly dependent on the transition metal. Catalyst productivity is dependent on the balance between activity and stability. Immobilisation can lead to a lower proportion of active species and therefore lower initial polymerisation activity, but nevertheless give higher polymer yields in cases where increased catalyst stability is obtained. Important physical factors are support porosity and the ability of a support to undergo progressive fragmentation during polymerisation, facilitating monomer diffusion through the growing catalyst/polymer particle. This article illustrates the importance of these factors in olefin polymerisation with both early- and late-transition metal catalysts, with particular reference to the use of silica and magnesium chloride supports as well as to effects of immobilisation on polymer structure and properties.
机译：当均相烯烃聚合催化剂固定在载体上时，其活性和稳定性取决于化学和物理作用。影响催化剂活性的化学因素包括容易形成的活性物种，而活性物种的形成很大程度上取决于过渡金属。催化剂的生产率取决于活性和稳定性之间的平衡。固定化可以导致活性物质的比例降低，因此降低了初始聚合活性，但是在获得提高的催化剂稳定性的情况下，却可以提供更高的聚合物收率。重要的物理因素是载体的孔隙率和载体在聚合过程中经历逐步断裂的能力，从而促进单体扩散通过正在生长的催化剂/聚合物颗粒。本文说明了这些因素在烯烃与早期过渡金属催化剂和晚期过渡金属催化剂聚合中的重要性，尤其涉及二氧化硅和氯化镁载体的使用以及固定化对聚合物结构和性能的影响。

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