微尺度通道中聚合物熔体的黏性耗散效应

Viscous dissipation effects of polymer melts in micro-channels

以双料筒毛细管流变仪和自行研制的黏性耗散测量装置为实验平台,通过对聚甲醛(POM)和聚苯乙烯(PS)两种聚合物熔体在不同剪切速率下,流经长径比相同的直径/当量直径分别为350μm和500μm的圆形及矩形截面微通道出口熔体温升的测量,研究了微尺度通道中聚合物熔体流动时的黏性耗散效应及其对熔体流变行为的影响。结果表明,两种截面微通道中的熔体黏性耗散效应均随剪切速率和微道直径/当量直径的增大而明显增强,其中矩形截面微通道中熔体的黏性耗散作用尤为强烈;且在相同实验条件下,结晶性的POM熔体因黏性耗散效应引起的微通道出口熔体温升值,高于非晶性的PS熔体。

The temperature increase of polyformaldehyde（POM）and polystyrene（PS）melts at the outlet of circular and rectangular micro-channels with the same aspect ratio and diameter/equivalent diameter of 350 and 500 μm was measured at different shear rates using two-cylinder capillary rheometer and self-developed viscous dissipation measurement device.The viscous dissipation and its effect on flow behavior of polymer melt in micro-channels were investigated.The results show that the viscous dissipation is enhanced obviously with the increase of shear rate and diameters/equivalent diameter value in the micro-channels.The viscous dissipation in the rectangular channel is much stronger than that in the circular one.Under the same experimental conditions,the temperature increase at the outlet of crystalline POM melt is larger than that of amorphous PS melt due to viscous dissipation.