Silica nano‐sol is the precursor (before gelation and drying) of silica gel and has much greater surface area than gel. In this study, a spherical commercial silica nano‐sol in toluene with a dimension of less than 50 nm was successfully used to support two bridged metallocenes (dicholo ‐ dimethyl silybis(indenyl) zirconium (IV) and dichloro – ethylenebis(indenyl) zirconium (IV),denoted by ZrSi and ZrEt, respectively). These sol‐supported catalysts showed significantly better propylene polymerization activities than gel‐supported catalyst reported earlier. The influences of solution co‐catalyst ([Al₄O₃Me₆]_n, n = 5–7, abbreviated as MAO) content and reaction time on polymerization were investigated. The increase of co‐catalyst concentration increased activity, polymer length, and melting temperature. Polymer assemblies produced with ZrSi/Sol changed from diamond‐shape to rod‐like shape as time proceeded. Uniform dumbbell – shaped micro‐sized polypropylene assemblies were obtained with catalyst ZrEt/Sol. The results were explained in terms of the penetration theory proposed before for multiphase mass transfer.

中文翻译：

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在搅拌釜反应器中用二氧化硅纳米溶胶负载的茂金属催化剂形成均匀的聚合物组装体

二氧化硅纳米溶胶是硅胶的前体（在凝胶化和干燥之前），比凝胶具有更大的表面积。在这项研究中，球形的商业二氧化硅纳米溶胶在甲苯中的尺寸小于50 nm，已成功用于支撑两个桥联的茂金属（二茂-二甲基硅双（茚基）锆（IV）和二氯-亚乙基双（茚基）锆（ IV），分别由ZrSi和ZrEt表示。这些溶胶负载的催化剂比之前报道的凝胶负载的催化剂表现出明显更好的丙烯聚合活性。溶液助催化剂（[Al ₄ O ₃ Me ₆ ] _n，研究了n = 5-7（缩写为MAO）的含量和聚合反应时间。助催化剂浓度的增加增加了活性，聚合物长度和熔融温度。随着时间的流逝，用ZrSi / Sol生产的聚合物组件从菱形变为棒状。用催化剂ZrEt / Sol获得均匀的哑铃状微型聚丙烯组件。根据先前提出的用于多相传质的渗透理论对结果进行了解释。