基于多阶压力控制的双峰泡孔聚合物发泡行为及性能

Foaming Behavior and Properties of Bimodal Cellular Polymer Based on Multi-step Pressure Control

双峰泡孔聚合物材料是聚合物泡沫的一种特殊结构类型材料,近年来受到了业界的广泛研究和关注。在超临界流体辅助间歇发泡工艺中,发泡体系的压力控制是诱导双峰泡孔形核和长大的关键因素。基于此,本研究构建了一种多阶压力控制聚合物间歇发泡系统,制备了具有典型双峰泡孔结构的聚苯乙烯泡沫材料,研究了不同一阶压降、一阶压降保压时间、二阶压降等工艺参数对聚合物发泡行为的影响以及所制备材料的隔热性能。结果表明,在饱和温度为90℃及以上时,一阶压降3 MPa和8 MPa条件下均能形成良好的双峰泡孔结构;饱和温度的升高、一阶压降保压时间的延长可以促进大泡孔的生长,而对小泡孔无明显影响;双峰泡孔聚苯乙烯泡沫材料具有良好的隔热性能,对于所制备的最大发泡倍率为47.27的泡沫材料,其热导率仅为72 mW/(m·K)。

Bimodal cellular polymer foam is a special structural material in polymer foam materials.It has been widely studied and concerned in recent years.In supercritical fluid assisted batch foaming process,the pressure control of foaming system is the key factor to induce the nucleation and growth of bimodal cellular foam.Based on this,a multi-step pressure control polymer batch foaming system was constructed.The polystyrene foam with typical bimodal foam structure was prepared.The effects of different first step pressure drop,holding time of first step pressure drop and second step pressure drop on the foaming behavior of the polymer,and the thermal insulation properties of the prepared material were studied.The results show that when the saturation temperature is above 90℃ and the first step pressure drop is 3 MPa and 8 MPa,a good bimo-dal cell structure can be formed.The increase of saturation temperature and holding time of first step pressure drop can promote the growth of big cells,but have no effect on the growth of small cells.The foamed polystyrene foam with bimodal cellular structure has good thermal insulation properties,and the thermal conductivity of the foamed material with a maximum foaming rate of 47.27 is only 72 mW/(m·K).