Shear and elongational rheology of polyethylenes with different molecular characteristics. II. Elongational rheology
Shear and elongational rheology of polyethylenes with different molecular characteristics. II. Elongational rheology
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DOI：
10.1002/app.25757
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发表时间：
2007-04
影响因子：
3
通讯作者：
Xiaoling Wei;J. Collier;S. Petrovan
中科院分区：
文献类型：
--
作者：
Xiaoling Wei;J. Collier;S. Petrovan
用毛细管流变仪测定了不同分子特性的聚乙烯在不同Hencky应变和温度下的拉伸粘度。模具的双曲线形状在整个模具中以恒定的拉伸应变速率建立了纯拉伸流场。研究了聚乙烯样品的分子量、分子量分布、长链支化等分子特性和温度、Hencky应变等加工条件对拉伸流变性的影响。良好的主曲线产生的温度和亨基应变偏移和同时偏移的温度和亨基应变。分子量分布和长链支化似乎促进应变速率变稀并降低拉伸粘度。© 2007 Wiley Periodicals，Inc. J Appl Polym Sci 104：1184-1194，2007
The elongational viscosities of polyethylenes with different molecular characteristics were measured at different Hencky strains and temperatures with a capillary rheometer by the replacement of the capillary cylindrical die with a hyperbolic converging die. The hyperbolic shape of the die established a purely elongational flow field at a constant elongational strain rate throughout the die. The effects of molecular characteristics such as the molecular weight, molecular weight distribution, and long-chain branching and processing conditions such as the temperature and Hencky strain on the elongational rheology of the polyethylene samples were studied. Good master curves were generated for temperature and Hencky strain shifting and simultaneous shifting with respect to both the temperature and Hencky strain. Both the molecular weight distribution and long-chain branching seemed to promote strain rate thinning and reduce the elongational viscosity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1184–1194, 2007