摘要
通过旋转流变仪对熔融态聚丙烯的流变特性进行研究,首先得到不同剪切流动条件下聚丙烯黏度及应力随剪切速率变化曲线,待剪切后的熔体冷却至室温时,再对经历不同速率流动后的聚丙烯试样进行X射线扫描,对其衍射图谱进行分析,最终得到聚合物剪切历史对其结晶行为的影响规律。结果表明,聚丙烯熔体在剪切流动时呈现明显的剪切变稀特征,其黏度随剪切速率的增大而降低并最终趋于一个恒定值,且剪切应力与剪切速率两者关系符合幂律模型;聚丙烯的结晶行为表现出明显的剪切历史依赖性,其结晶度、晶粒尺寸和晶粒取向均与剪切速率呈正相关性。
The rheological properties of molten polypropylene （PP） were studied by rotational rheometer. The curves of viscosity and shear stress of PP under different shear rates were obtained. Then the X-ray scanning pattern of PP samples with different rate shear flow was carried out and thus the influence of shear history on the crystallization behavior of PP was analyzed by its diffraction pattern. The experimental results show that the viscosity of the PP melt decreases with the increase of the shear rate and it tends to a constant value, and the relationship between shear stress and shear rate is consistent with power-law model; the crystallization behavior of PP shows a significant dependence on the shear history, and its crystallinity, grain size and orientation are positively correlated with shear rate.
出处
《塑料工业》
CSCD
北大核心
2017年第12期74-77,95,共5页
China Plastics Industry
基金
国家自然科学基金项目(51365038
51565034)
江西省自然科学基金项目(20161BAB206123)
关键词
聚丙烯
剪切流变
流变特性
结晶
Polypropylene
Shear flow
Rheologieal Properties
Crystallization
