Wall slip behavior of polymer melts on capillary rheometer

来源期刊:中南大学学报(英文版)2008年增刊第1期

论文作者:廖华勇 谭中欣 邹国享 丁永红 陶国良

文章页码:98 - 101

Key words:polymer; wall slip; critical shear stress; capillary rheometer; temperature dependence

Abstract: Wall slip behavior of three commercial polymer melts polypropylene(iPP), low-density polyethylene (LDPE)(branched chains) and high-density polyethylene (HDPE)(linear chains) were studied by using a capillary rheometer with twin bores at different temperatures. The results show that a sudden first-stick-then-slip transition was observed for HDPE and a first-slip-then-stick transition was observed for LDPE and iPP as the shear rate sweep was done in an increased order, which shows that the chain structure has an obvious effect on the wall slip behavior of polymers. The critical shear stress for the onset of stick-slip transition increases linearly with temperature for HDPE, which accords with the disentanglement mechanism proposed by Brochard and de Gennes. While the extrapolation length used to quantify the magnitude of the transition remains about 0.05-0.09 mm for HDPE at 150-230 ℃. Also the relationship between the critical shear stress for the onset of wall slip and the molecular mass for polymer samples agrees with the disentanglement model of Brochard and de Gennes. The onset of slip-stick transition for LDPE and iPP at a critical shear stress may be interpreted as the shear thinning of the polymer chains at high shear rates, preventing further development of wall slip behavior.

基金信息:the Young Teacher’s Scientific Research Fund of Jiangsu Polytechnic University, China

有色金属在线官网  |   会议  |   在线投稿  |   购买纸书  |   科技图书馆

中南大学出版社 技术支持 版权声明   电话:0731-88830515 88830516   传真:0731-88710482   Email:administrator@cnnmol.com

互联网出版许可证:(署)网出证(京)字第342号   京ICP备17050991号-6      京公网安备11010802042557号