超声振动对聚苯乙烯熔体解缠结的影响

用自行研制的超声振动挤出装置,采用控制变量的方法,改变超声功率和冷却条件,在水冷和空冷的条件下研究超声振动对聚苯乙烯(PS)熔体解缠结的影响。结果表明,在超声功率为200 W的范围内,聚苯乙烯并未发生明显的降解,挤出过程表观黏度下降的原因是超声的热效应及超声的空化效应和机械效应,分别占比56%和44%。通过定量缠结点间平均相对分子质量发现,水冷能够实现对解缠结结构的较大保留,聚苯乙烯的缠结点间相对分子质量最大提升了83%。熔体流动速率数据显示,经过600 s的热历史,所有样品的熔体流动速率值趋于一致,缠结结构基本回复。

Effect of Ultrasonic Vibration on the Disentanglement of Polystyrene Melt

The influence of ultrasonic vibration on polystyrene(PS)melt disentanglement was studied under the condition of water cooling and air cooling by changing the ultrasonic power and cooling conditions.The results show that no significant degradation of polystyrene occurs within the range of 200 W of ultrasonic power,and the decrease of apparent viscosity in the extrusion process is due to the thermal effect of ultrasound,the cavitation effect and the mechanical effect of ultrasound,accounting for 56%and 44%,respectively.By quantifying the average relative molecular mass between the entanglements,it is found that water cooling can achieve greater retention of the untangling structure,and the maximum molecular weight of polystyrene is increased by 83%.The melt flow rate data show that after a thermal history of 600 s,melt flow rate values of all samples tend to be the same,and the entanglement structure is basically recovered.