摘要
采用高压毛细管流变仪和先进流变扩展系统相结合的方法研究了PVDF熔体在较宽剪切速率范围（1×10^-2～5×10^-1）的流变行为。结果表明，在极低的剪切速率范围内．PVDF熔体黏度几乎不随剪切速率的变化而变化，表现出牛顿流体特性；而在较高的剪切速率范围内．PVDF熔体表现黏度随剪切速率的增加而明显降低，表现出强烈的剪切变稀行为，为假塑性非牛顿流体。同时探讨了分子量、剪切速率、温度对PVDF熔体非牛顿指数、粘流活化能等流变特性的影响。
Rheological behavior at a wide range of shear rates（10^-z s^-1～ 5×10^3 s^-1） for Poly （vinylidene fluoride）（PVDF） melt was investigated by means of high pressure capillary rheometer and advanced rheological extension system （ARES）. At very low shear rates, PVDF melt was Newtonian fluid, the melting viscosity of which was almost independent of shear rates. However, it was non-Newtonian fluid at higher shear rates, and its melting viscosity decreased with the increase of shear rates. Several factors, such as molecular weights, temperature and shear rates, on apparent viscosity, non-Newtonian exponent and flow activation energy of PVDF melt were also discussed. The results show that increasing temperature and decreasing molecular weights or shear rates can cause an increase of non-Newtonian exponent of PVDF melt. Flow activation energy of PVDF melt which accorded with the sensitivity of apparent viscosity on temperature increases with decrease of shear rates. At low shear rates, apparent viscosity of PVDF melt can be effectively decreased by increasing temperature.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2006年第2期123-125,129,共4页
Polymer Materials Science & Engineering
基金
国家重点基础研究发展计划项目(2003CB615705)
关键词
聚偏氟乙烯
流变特性
表观黏度
粘流活化能
非牛顿指数
poly （vinylidene fluoride）
rheologieal properties
apparent viscosity flow activation energy
non-Newtonian exponent
