中文摘要：

合成了2种新型硅烷化合物双环己基二甲氧基硅烷（Donor-H）、双哌啶二甲氧基硅烷（Donor-Py），将其与工业化的环己基甲基二甲氧基硅烷（Donor-C）分别作为外给电子体，用于MgCl2负载的Ziegler-Natta催化剂催化丙烯聚合，通过DSC、GPC、SSA和13C-NMR等分析手段研究了3种外给电子体取代基的变化对催化剂的催化活性、氢调敏感性、聚丙烯的等规度、分子量分布、结晶能力、等规序列分布的影响．结果表明，随着外给电子体取代基体积的增大，外给电子体的给电子能力逐渐增强．与Donor-C相比，随着外给电子体取代基体积的增大，合成的具有较大取代基的Donor-H和Donor-Py用于丙烯聚合时都表现优异的催化性能，特别是新型含有N杂原子的氨基硅烷类Donor-Py为外给电子体的催化剂的催化活性和制备的聚丙烯的等规度最高，聚丙烯的熔融指数可调范围最宽，结晶能力更强．氨基硅烷类Donor-Py制备的聚丙烯SSA热分级后的高等规组分含量最多，可高达64．5％，聚丙烯等规序列长度最长，聚丙烯的等规序列分布最窄，而且13C-NMR结果也表明聚丙烯等规序列长度MSL最长，聚丙烯的分子链最规整．

英文摘要：

The silane compounds including dicyclohexyldimethoxysilane （ Donor-H ） and dipiperidinedimethoxysilane （Donor-Py） were first synthesized. Then they and the industrial external donor cyclohexylmethyldimethoxysilane （Donor-C） were employed for propylene polymerization with MgC12- supported Ziegler-Natta catalyst, respectively. The effects of the changeable substitutes of the three external donors on the catalytic activity, hydrogen response, molecular weight distribution, crystalline ability, isotactic sequence length and isotactic sequence length distribution were studied by differential scanning calorimetry （DSC）, gel permeation chromatography （GPC）, self-nucleation and annealing （SSA） and 13C-NMR. The results indicated that the electron-donating ability of the external electron donors was enhanced with the increase of the bulkiness of the changeable substituted groups in the external donors. Compared with the external donor Donor-C,the synthesized external donors Donor-H and Donor-Py had the excellent performance in the catalytic activity, crystallization ability and isospecificity of polypropylene for propylene polymerization with the increase of the bulkiness of the substituted groups in the external donors Donor-H and Donor-Py. Especially,when the Donor-Py was used as external donor, the catalyst showed the highest catalytic activity, and the prepared polypropylene exhibited the highest isotacticity, the strongest crystallization ability and the widest melt index. The GPC data also showed the external donor Donor-Py was benefit for obtaining broad molecular weight distribution polypropylene than the other two external donors Donor-H and Donor-C. The SSA results showed that the polypropylene prepared by the external donor Donor-Py had the largest relative content of higher isotactic components and the longest isotactic sequence length of polypropylene, and the narrowest isotactic sequence length distribution. The 13C-NMR results also showed that the increase of the bulkiness of the subs