کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5183669 | 1381025 | 2011 | 8 صفحه PDF | دانلود رایگان |
According to the observable evidence from 1H and 13C nuclear magnetic resonance and mass spectrometry, new dinuclear constrained geometry catalysts (DCGCs) with a structure of [{Ti(η5:η1-(C9H5)Si(CH3)2NtBu)Cl2(CH2)n}2(C6H4)] [n = 0 (10), n = 1 (11), n = 2 (12)] were synthesized successfully. Copolymerization of ethylene and styrene were tested by using three new DCGCs and Dow CGC. The catalyst activity, the molecular weight (MW) and styrene content of the copolymers were sharply improved as the bridge structure was transformed from para-phenyl (10) to para-xylyl (11) and para-diethylenephenyl (12). The activity of 11 and 12 was about four to five times greater than that of 10 regardless of the polymerization conditions. In addition, the capability to form high MW polymers increased in the order of Dow CGC â 10 < 11 < 12. The styrene contents in copolymers generated by 11 and 12 were higher than those of 10.
Journal: Polymer - Volume 52, Issue 2, 21 January 2011, Pages 318-325