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聚丙烯(PP)熔体强度低,发泡性能差。将两种PP材料共混来改善PP的发泡性能,研究PP材料性质对共混体系微孔结构的影响。研究表明:在各种发泡温度下使用纯PP材料很难制得泡孔结构好的微孔材料,而两种PP材料共混以后再进行微孔发泡,泡孔结构得到了改善。与两种相似熔点和黏度的PP共混材料相比,在高黏度的PP中混入少量的低熔点、低黏度PP时,可以制得泡孔结构更好的微孔材料。研究了共混比例对泡孔形态的影响,并从熔体黏弹性和结晶性能两方面分析了泡孔结构变化的机理。
Polypropylene (PP) has low melt strength and poor foaming properties. The two kinds of PP materials were blended to improve the foaming properties of PP, and the influence of PP material properties on the microporous structure of the blends was studied. The results show that it is difficult to obtain microporous materials with good cell structure by using pure PP materials at various foaming temperatures. However, the cellular structure of the two PP materials is further foamed after being blended, and the cell structure is improved. Compared with two kinds of PP blends with similar melting point and viscosity, microporous materials with better cell structure can be obtained when a small amount of low melting point and low viscosity PP is mixed into high viscosity PP. The effects of blending ratio on cell morphology were investigated. The mechanism of cell structure change was analyzed from the viewpoint of melt viscoelasticity and crystallinity.