成核剂对聚丙烯釜压发泡的影响

Effect of Nucleating Agents on Polypropylene Batch Foaming Process

用超临界二氧化碳(CO_2)釜压发泡的方法.研究了成核剂类型、成核剂粒径以及成核剂添加量对聚丙烯(PP)发泡材料泡孔结构的影响。结果表明,用碳酸钙(CaC()3)作成核剂时PP泡沫的泡孔完整性高,泡孔尺寸分布均匀,且发泡倍率比添加蒙脱土及滑石粉时的要大;成核剂粒子粒径越小,体系的成核点越多,发泡时产生的气泡核越多,所得到的PP泡沫的泡孔L密度越大,但是由于纳米碳酸钙(nano-CaCO_2)更容易出现团聚现象,直接导致最终发泡制品产生泡孔破裂以及发泡倍率的降低;成核剂CaCO_3的添加量为3份时,与添加1份和5份相比,可得到发泡倍率更高,泡孔密度更大的PP泡沫。

Influence of types,particle sizes,and dosages of nucleating agent on the cell structure of the batch foaming of polypropylene with super-critical carbon dioxide was investigated.When calcium carbonate was used,better cell integrity and more uniform cell size distribution,and higher expansion ratio were obtained compared with the foam using talc and montmorillonite.The smaller the particle size,the more the nucleation sites,and the larger the cell density.A loading of 3 phr calcium carbonate was optimal to achieve high expansion ratio and cell density.