超声振动对玻纤增强聚丙烯塑件性能的影响

Effect of Ultrasonic Vibration on Glass Fiber Reinforced Polypropylene Parts

采用短玻纤增强聚丙烯(GFPP)材料,进行了矩形壳体塑件不同成型阶段施加超声振动的注射成型试验,并借助XRD、SEM观测和拉伸实验等方法,研究了超声振动对成型塑件内部结晶度及其力学性能的影响。结果表明:在充模阶段施加超声功率大于400W时,塑件的结晶度明显升高,但其拉伸强度增加较小;在保压及冷却阶段施加不同超声功率时,塑件内部的结晶度和拉伸强度均增加较小;而在注射成型全过程施加超声振动,超声功率小于400W时,塑件的结晶度和拉伸强度均明显提高;增大超声功率,塑件的结晶度减小,但拉伸强度明显增大。相比于未加超声振动,塑件不同成型阶段施加超声振动,均有助于塑件内部生成更多的结晶结构,提高塑件的力学性能。

Short glass fiber reinforced polypropylene(GFPP)was used for injection molding of rectangular shell parts with ultrasonic vibration at different molding stages.The effects of ultrasonic vibration on the internal material crystallinity and mechanical properties of tHe parts were experimentally studied by means of XRD,SEM and tensile test.The results show that the effect of ultrasonic strengthening is different in different molding stages.On one hand,in the filling stage,the material crystallinity of the parts increases obviously when the ultrasonic power is more than 400W,but the tensile strength increases slightly・On the other hand,the crystallinity and tensile strength can just increase slightly even if the ultrasonic power is higher or lower in the holding and cooling stages.Besides,it is found that while the ultrasonic power is kept less than 400W in the whole process injection molding,the crystallinity and tensile strength of the parts are significantly improved.And while the ultrasonic power is kept higher(than 400W),the crystallinity may decrease as well as the tensile strength may increase.Compared with injection molding without ultrasonic vibration,applying ultrasonic vibration at different forming stages of the part are all help to generate more crystalline structures and to improve the mechanical properties.