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使用双料筒毛细管流变仪测试PS熔体在温度为220、240、260℃和剪切速率为500～2万s-1的条件下流经截面为320μm×300μm、500μm×400μm、1 000μm×785μm,长径比不同的矩形口模时的黏度。实验结果表明:在同一温度和剪切速率条件下,熔体黏度随口模截面尺寸减小而减小;随口模长径比增大而增大。将实验黏度值和两种不同的微尺度黏度模型的理论值进行了比较,发现考虑长径比的微尺度黏度模型更能表征矩形微通道中PS熔体的流变特性。
The PS melt was tested using a dual barrel capillary rheometer at a flow rate of 320 μm × 300 μm, 500 μm × 400 μm, 1 000 μm × 785 μm at a temperature of 220, 240, 260 ° C and a shear rate of 500 to 20,000 s-1 , The aspect ratio of different rectangular die viscosity. The experimental results show that at the same temperature and shear rate, the melt viscosity decreases with the decrease of the cross-sectional area of the die, and increases with the increase of the die-length ratio of die. The experimental viscosity values were compared with the theoretical values of two different microscale viscosity models. It was found that the rheological properties of PS melt in rectangular microchannels can be better characterized by the microscale viscosity model considering the aspect ratio.