超临界CO_2发泡聚苯乙烯工艺研究

Study of Polystyrene Foaming Processes with Supercritical Carbon Dioxide as Foaming Agent

以超临界CO_2为发泡剂,采用釜压法在不同发泡工艺条件下制备了聚苯乙烯(PS)发泡试样,通过扫描电子显微镜对PS发泡试样的泡孔形貌进行了表征,探讨了不同发泡工艺对PS发泡试样发泡性能的影响。结果表明,随发泡温度的升高,PS发泡试样泡孔尺寸增大,泡孔密度下降,而泡沫密度呈现先降低后升高的趋势,发泡倍率与此相反;增大保压时间和保压压力,可提高试样的发泡效果。当发泡温度为136℃,保压压力为20 MPa,保压时间为4 h时,PS发泡试样的发泡效果最好,其泡沫密度为0.043 g/cm^3,发泡倍率为24.4,泡孔尺寸为59.8μm,泡孔密度为6.20×107个/cm^3。

Taking supercritical carbon dioxide as foaming agent,polystyrene (PS) foams were prepared by the autoclave foaming method with different foaming processes. The foaming morphologies of PS foams were observed by scanning electron microscope and the effects of different foaming processes on foaming performances of PS foams were discussed. The results show that with the increase of foaming temperature,the cell size of the PS foam increases and cell density decreases,but the foam density decreasesfirstly and increases lastly,the change of expansion ratio is opposite. Increasing the holding time and holding pressure can improve the foaming effects. When the foaming temperature is 136℃,holding pressure is 20 MPa,holding time is 4 h,the foaming effects of the PS foam are best,the foam density is 0.043 g/cm3,expansion ratio is 24.4,cell size is 59.8μm and cell density is 6.20×107 cells/cm3.