外场作用下聚合物滞后生热效应

Hysteresis thermogenous process of polymer material under vibrational force field

为了研究振动参数对聚合物黏弹性能及塑化成型过程的影响,深入分析了振动场的作用机理,揭示了相位角与滞后生热率之间的关系,得出了振动场作用下聚合物塑化成型速率表达式,最后通过聚对苯二甲酸乙二醇酯(PET)动态毛细管挤出以及多维振动塑化成型设备进行实例计算和实验研究,实验结果和理论计算值符合得很好,并得出结论:PET塑化速率随振动频率的增加呈先增加后减小的趋势,当激振频率趋向于材料固有频率时(振动频率约为15Hz时),PET塑化速率达到最大值,当振幅为6MPa时,其值约为22g/min,为相同振幅下,频率为10Hz时的1.75倍;在材料的固有频率附近,适当增加激振振幅,能够极大地提高聚合物成型速率.本研究将会为聚合物低温成型新方法和新设备研究提供可靠的理论基础.

A thorough analysis of the mechanism of vibrational force field on polymer processing was carried out to investigate the effect of vibration parameters on polymer viscoelasticity and plastic forming processing. The relationship between phase angle and lagging heat generation rate as well as the expression of polymer plasticizing rate under vibrational force field was obtained. To verify the theory,PET was adopted for example calculation and in expriments with dynamic capillary rheometer and mlti-dimentional vibration induced plastic forming equimpment. The result from calculation agrees well with that from experiment. Besides,it can be concluded that the plasticizing rate of PET increases at first and decreases afterwards with increasing vibration frequency. It reaches the peak at vibration frequency equivalent to the natural frequency of PET of about 15 Hz. The value remains at 22 g /min with the natural vibration frequency when the vibration amplitude is 6 MPa,being 1. 75 fold that with vibration frequency of 10 Hz. Therefore,the plasticizing rate of polymer can be significantly improved by increasing the vibration amplitude. The exploration in this paper supplies reliable thoeretical reference for novel polymer low temperature moulding technique and equipments.