超声辐照对高密度聚乙烯热稳定性及结晶性的影响

Effect of Ultrasonic Irradiation on Thermal Stability and Crystallinity of High Density Polyethylene

采用自行设计的超声辐照装置,研究了不同超声辐照功率(0 W,100 W,200 W,300 W,400 W)及不同超声辐照时间(0 min,5 min,10 min,15 min)对高密度聚乙烯(HDPE)的热稳定性、结晶性及流变性能的影响。通过同步热分析仪分析得出超声辐照功率越大,辐照时间越长,HDPE的热稳定性能越好,400 W下辐照15 min的HDPE 5%失重温度比未辐照的HDPE 5%失重温度提高了近26%;通过X射线衍射及差示扫描量热分析得出超声辐照会有细化晶粒的作用,辐照功率和辐照时间对结晶度均有影响且在功率200 W辐照5 min时,结晶度达到最大;通过旋转流变仪表征得出经超声辐照处理的HDPE的剪切黏度都有所降低,在400 W的超声功率下辐照10 min时,剪切黏度达到最低,利于加工成型。

Effects of different ultrasonic irradiation powers(0 W,100 W,200 W,300 W,400 W)and different ultrasonic irradiation time(0 min,5 min,10 min,15 min)on high-density polyethylene(HDPE)were studied by using the self-designed ultrasonic irradiation equipment.According to the analysis of synchronous thermal analyzer(TGA),the higher the irradiation power is,the longer the irradiation time is,the better the thermal stability of HDPE is.The 5%mass loss temperature of HDPE at 400 W for 15 min is higher than that of non-irradiated HDPE.The 5%mass loss temperature is increased by nearly 26%.XRD and DSC analysis show that the ultrasonic irradiation has the effect of refining crystal grains,irradiation power and irradiation time have effect on the crystallinity of HDPE which reaches the maximum when the power is 200 W for 5 min.The shear viscosity of HDPE treated by the ultrasonic rheometer is reduced by the rotary rheometer.Under the ultrasonic power of 400 W and the irradiation time of 10 min,the shear viscosity is the lowest,which is favorable for processing.