旋转流变仪在聚乙烯表征中的应用

APPLICATION OF ROTATIONAL RHEOMETERIN THE CHARACTERIZATION OF POLYETHYLENE

介绍旋转流变仪的测试原理、测试方法以及在聚乙烯流变行为测试中的应用,主要是对聚乙烯的黏弹特性、流变行为进行表征。使用旋转流变仪分析4种聚乙烯管材料的流变性能、相对分子质量及其分布方面的差异,并对加工性能进行比较。结果表明:相对分子质量由大到小依次为PE-4、PE-3、PE-2、PE-1,与凝胶渗透色谱法测得的相对分子质量趋势一致;PE-1和PE-2的分子量分布较窄,PE-3和PE-4的分子量分布较宽;PE-4对剪切速率最敏感,剪切黏度随剪切速率升高降幅最大。

The test principle, method and application of rotational rheometer in the characterization of polyethylene were introduced, the viscoelastic properties and rheological behavior of polyethylene were mainly studied. By means of rotational rheometer,the rheological properties of four kinds of polyethylene pipe materials( PE-1,PE-2,PE-3,PE-4) were compared,their difference in relative molecular weight and molecular weight distribution were analyzed,and their processing properties were compared. The results showed that the relative molecular weight of the four kinds of polyethylene in the order of large to small was PE-4、PE-3、PE-2、PE-1,which was consistent with the test results by gel permeation chromatography. The molecular weight distribution of PE-1 and PE-2 was relatively narrow,while the molecular weight distribution of PE-3 and PE-4 was relatively wide. PE-4 was the most sensitive to the shear rate,its shear viscosity was decreased the most along with increase of the shear rate.