Home | My Profile | Contact Us
Research Trends Products  |   order gateway  |   author gateway  |   editor gateway  
Register | Forgot Password

Author Resources
 Author Gateway
 Article submission guidelines

Editor Resources
 Editor/Referee Gateway

 Regional Subscription Agents/Distributors
Current Topics in Catalysis   Volumes    Volume 12 
Controlling long-chain branch formation in polyethylene
E. D. Schwerdtfeger, M. D. Jensen, Q. Yang, M. P. McDaniel
Pages: 1 - 27
Number of pages: 27
Current Topics in Catalysis
Volume 12 

Copyright © 2016 Research Trends. All rights reserved

Several catalyst and reactor variables have been observed to exert a strong influence on long-chain branch (LCB) formation during ethylene polymerization while using Phillips Cr/silica or metallocene type catalysts. These include ethylene concentration, solution versus slurry process, catalyst calcination temperature, Cr and Ti loading, the presence or absence of cocatalysts or poisons, catalyst porosity and nano-structure, and active site Lewis acidity and/or sterics. These LCB responses are reviewed and various possible explanations for each are suggested. One conclusion from this study is that LCB formation is much more selective than is usually envisioned from the simple inter-molecular mechanism of random macromer insertion that is widely accepted, and analogous to comonomer insertion. In fact, some of these variables, such as the catalyst porosity, can swing LCB content over an extremely broad range under otherwise identical catalyst and reaction conditions. To account for such unexpected behavior one or more modifications of the mechanism of LCB formation is needed. 
Buy this Article


Buy this article
Buy this volume
Subscribe to this title
Shopping Cart

Quick Links
Search Products
Browse in Alphabetical Order : Journals
Browse by Subject Classification : Journals

Ordering Information Ordering Information
Downloadable forms Downloadable Forms