کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6466376 1422963 2017 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Production of bimodal polyethylene on chromium oxide/metallocene binary catalyst: Evaluation of comonomer effects
ترجمه فارسی عنوان
تولید پلی اتیلن بموادال بر روی اکسید کروم / کاتالیزور دوتایی فلزلوئن: ارزیابی اثرات کامنومر
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی


- Ethylene/α-olefins copolymerizations on chromium-metallocene catalyst are evaluated.
- Chromium contribution increases by using comonomers, leading to wider MWDs.
- Hydrogen can be used for tuning catalytic activity and polyethylene bimodality.
- Comonomer placement across MWD of bimodal polyethylene shows a growing profile.

A novel option to produce bimodal polyethylene is by using binary catalytic systems, able to generate polyethylene chains with different predominant molecular weights in only one-step polymerization process. In this work, we explore in depth the catalytic behavior of a binary chromium-metallocene catalyst in the co-polymerizations of ethylene with 1-butene or 1-hexene looking for the production of bimodal polyethylene with an adequate comonomer profile across its molecular weight distribution. Likewise, the effect of the hydrogen together with comonomers was also evaluated for controlling polymers properties. Results indicate that the relative contribution of chromium and metallocene sites in the binary catalyst is strongly affected by using comonomers. Specifically, chromium contribution noticeably increases when using 1-hexene or 1-butene due to the positive comonomer effect observed in the individual chromium catalyst. The methodology used for hydrogen supply (continuous or discontinuous addition) plays a key role for tuning catalytic activity and polyethylene bimodality. Finally, comonomer placement across the molecular weight distribution of bimodal polyethylenes shows a growing profile, with a higher SCB concentration in the longest polymer chains than that obtained for a commercial PE100 sample.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Engineering Journal - Volume 315, 1 May 2017, Pages 46-57
نویسندگان
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