聚乙烯树脂熔体拉伸流变性能研究

选取了3种不同分子链结构的聚乙烯树脂,采用SER(sentmanat extensional rheometer)夹具旋转流变仪、熔体拉伸流变仪分别研究了其熔体瞬态拉伸黏度、熔体拉伸强度和拉伸黏度等流变性能。结果表明,随Hencky形变的增大,高密度聚乙烯(PE-HD)100N的熔体瞬态拉伸黏度的增长趋势逐渐放缓;低密度聚乙烯(PE-LD)2420F出现明显的拉伸硬化现象,熔体瞬态拉伸黏度急剧增大;线形低密度聚乙烯(PE-LLD)7050熔体拉伸黏度较低,迅速形成平台后开始减小;3个样品中100N的熔体强度和拉伸黏度均高于2420F和7050,7050最低。

Study on Tensile Rheological Properties of Polyethylene Melt

The rheological properties of three types of polyethylene resins with different molecular chain structures were investigated by using a rotary rheometer(sentmanat extensional rheometer)and a melt tensile rheometer.These rheological properties include melt transient tensile viscosity,melt tensile strength and tensile viscosity.The results indicated that the growth of the transient tensile viscosity of PE-HD-100N melt tended to slow down gradually with an increase in the Hencky deformation.There was an obvious transient tensile hardening phenomenon appearing in PE-LD-2420F,and the tensile viscosity of its melt increased sharply.The tensile viscosity of the melt of PE-LLD-7050 was low,and it began to decrease after the rapid formation of the platform.The test result of melt tensile indicated that the melt strength and tensile viscosity of PE-HD-100N were higher than those of PE-LD-2420F and PE-LLD-7050.PE-LLD-7050 presented the lowest melt strength and tensile viscosity.