以水为共发泡剂的超临界CO_2发泡制备PEI微孔材料

Preparation of Polyetherimide Microporous Materials by Supercritical CO_2 Foaming:Inspection on Water as Co-Blowing Agent

采用快速泄压法,分别以CO_2和CO_2/水为发泡剂,制备聚醚酰亚胺(PEI)微孔发泡材料。通过扫描电镜、热重分析等考察了发泡温度和饱和压力等参数对发泡材料结构、形貌与热稳定性的影响。结果表明,单独使用超临界CO_2为发泡剂时,发泡温度为220℃,压力为20MPa时,仅能得到最高倍率为2.7的发泡制品;以CO_2/水为发泡剂时,可发泡窗口整体向低温移动,下限可降至170℃,上限为220℃。发泡倍率明显增大,在发泡温度200℃,压力25 MPa时可得最高倍率为8.7的发泡样品;共发泡剂对发泡样品的热稳定性影响甚微。

Polyetherimide（ PEI） microporous foaming materials were fabricated by rapid pressure relief method employing CO2 and CO2/water as foaming agent respectively. The effects of foaming temperature and saturation pressure on the structure,morphology and thermal stability of foamed materials were investigated by SEM and TG. The results show that the supercritical CO2 utilized as foaming agent alone with the foaming temperature of 220 ℃ and the pressure of 20 MPa,the expansion ratio is up to only 2. 7. The CO2/water,working as co-agent,however,makes foam window as a whole move to low temperature,with the lowest limit reduced to 170 ℃,and the upper limit improved to 220 ℃. The foaming ratio increases obviously,and the foaming sample with the highest magnification of 8. 7 is obtained when the foaming temperature is 200 ℃ and the pressure is 25 MPa. The co-foaming agent has little effect on the thermal stability of the foaming sample.