| METALLOCENE POLYETHYLENES WITH BROAD OR BIMODAL MOLECULAR WEIGHT DISTRIBUTION |
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| 作者姓名： | 田军 王佰全 陈寿山 刘宇 黄葆同 |
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| 作者单位： | Changchun Institute of Applied Chemistry，Chinese Academy of Sciences Changchun 130022，China，Nankai University，Tianjin 300071，China，Nankai University，Tianjin 300071，China，Changchun Institute of Applied Chemistry，Chinese Academy of Sciences Changchun 130022，China，Changchun Institute of Applied Chemistry，Chinese Academy of Sciences Changchun 130022，China |
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| 摘 要： | Seven new binuclear titanocenes with different linking bridges, unsubsti-tuted or substituted on the Cp rings, were synthesized and tested for their effect on ethylenepolymerization in the presence of MAO. The polyethylenes thus obtained had broad MWDor even bimodal GPC curves, as compared with that from two reference mononuclear ti-tanocenes. This is explained by the difference in degree of steric hindrance around the activecenter sites imposed by the bulky substituted ligands assuming different configurations inthe rotation of the catalyst molecules. Lower polymerization temperatures alleviate theeffect of these configuration differences, as reflected in change in MW and M_w/M_n. Thiseffect is not caused by decomposition or disproportionation of the binuclear titanocenes asevidenced by the stability of the catalyst.
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| 收稿时间： | 1998-04-14 |
METALLOCENE POLYETHYLENES WITH BROAD OR BIMODAL MOLECULAR WEIGHT DISTRIBUTION* |
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| TIAN Jun,WANG Baiquan,CHEN Shoushan,LIU Yu,HUANG Baotong.METALLOCENE POLYETHYLENES WITH BROAD OR BIMODAL MOLECULAR WEIGHT DISTRIBUTION[J].Chinese Journal of Polymer Science,1998,0(4):370-376. |
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| Authors: | TIAN Jun WANG Baiquan CHEN Shoushan LIU Yu HUANG Baotong |
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| Institution: | 1.Changchun Institute of Applied Chemistry; Chinese Academy of Sciences Changchun 130022; 2.China Nankai University; Tianjin 300071; China; |
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| Abstract: | Seven new binuclear titanocenes with different linking bridges, unsubsti-tuted or substituted on the Cp rings, were synthesized and tested for their effect on ethylenepolymerization in the presence of MAO. The polyethylenes thus obtained had broad MWDor even bimodal GPC curves, as compared with that from two reference mononuclear ti-tanocenes. This is explained by the difference in degree of steric hindrance around the activecenter sites imposed by the bulky substituted ligands assuming different configurations inthe rotation of the catalyst molecules. Lower polymerization temperatures alleviate theeffect of these configuration differences, as reflected in change in MW and M_w/M_n. Thiseffect is not caused by decomposition or disproportionation of the binuclear titanocenes asevidenced by the stability of the catalyst. |
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| Keywords: | Metallocene polyethylene Binuclear titanocenes |
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