测定本体粘度的拉伸蠕变方法

测量高聚物粘度的方法很多。对高粘度样品经常采用拉伸蠕变方法,这时测定的是拉伸粘度习η_T: σ=η_T(?)_f其中σ是拉伸应力,(?)_f是由此引起的拉伸流动的应变速率。由于高聚物是粘弹性材料。因此必须设法区分弹性形变和流动形变,才能得到η_T值。Bueche和Kraus等曾分别用拉伸蠕变方法研究聚甲基丙烯酸甲酯和聚顺丁二烯的本体粘度。他们所用的处理方法有三

MEASUREMENT OF BULK VISCOSITY BY TENSILE CREEP METHOD

The data treatment in viscosity measurement by tensile creep method was discussed. A method which may be used for polymer samples with high viscosity and low modulus was proposed. The measurements of two poly-cis-1,4, butadiene samples showed that due to the difficulty to avoid wholly the influence of elastic deformation during the creep process of these samples, the previous method which was based on the assumption of the establishment of a pure steady flow state would deviate the viscosity values to one order of magnitude lower.