轮胎胶料挤出流动中粘弹特性分析

Analysis for viscoelasticity in extrusion flow of retread tire compounds

考察了洞口胶、缓冲胶和翻胎胎面胶胶料在毛细管挤出流动中的粘弹性行为及机理。结果表明 ,在温度为 90℃和表观剪切速率为 1～ 10 3s-1的操作条件下 ,3种胶料的剪切流动均服从幂律 ,且非牛顿指数值相差不大 ;入口压力降和挤出膨胀比均随表观剪切速率的增大而呈非线性函数形式增大 ,且洞口胶的挤出膨胀比最大 ,缓冲胶最小 ;而缓冲胶的入口压力降最大 ,洞口胶最小。应用挤出膨胀方程估算的试样剪切弹性模量与壁面剪切应力呈线性函数关系 ,其预测值与文献值相当接近。

The viscoelastic behaviour and mechanism in capillary extrusion flow of three retread tire compounds (cavity stock,buffer stock and retread stock) were investigated.The results showed that under the operation conditions with the temperature of 90 ℃ and the apparent shear rate (γ a) of 1～10 3 s -1 ,the shear flows of all three samples obeyed the power law and their non Newtonian index values were close to each other;the entry pressure drop (Δ P e) and the die swell ratio ( B ) increased nonlinearly with the increase of γ a;the B value for cavity stock was the highest,and that for buffer stock was the lowest,but it was contrary in terms of Δ P e;and the shear modulus ( G ) of the samples estimated by means of a die swell equation were the linear functions of the wall shear stresses,and close to those reported in previous literatures.