晶体形态对β聚丙烯单向拉伸成孔性能的影响

Effect of the Crystalline Morphology on Pore Generation of β-PP Under Uniaxial Tension

通过扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和广角X射线衍射(WAXD)研究了β晶的晶体形态对β聚丙烯单向拉伸成孔性能的影响。结果表明,随着熔融温度的提高,由于β成核剂(酰胺类成核剂TMB-5)溶解性的不同,得到的β晶的晶体形态截然不同。将具有不同β晶晶体形态的β-PP铸片进行单向拉伸,发现其成孔情况呈现较大差异,在较低熔融温度下(180℃、200℃)得到的、具有球晶形态的β晶铸片单向拉伸后产生明显的微孔,且分布均匀排列规整;而更高温度(220℃、240℃)下制得的、具有横晶及花状晶体形态的β-PP铸片在相同的实验条件下观察不到微孔结构,说明前者的β晶聚集态结构更容易在单向拉伸中产生微孔。

The influence of crystlline morphology on pore generation of β-PP under uniaxial tension was investigtated by SEM, DSC and WAXD. The results show that different final molten temperture （Tf） causes the β- PP showing different crystlline morphology. When the T is 180 ℃ or 200 ℃, the β-PP forms β-spherulites. When the Tf is 220 ℃ the β-PP shows β-transcrystlline entities. When the Tf is 240 ℃, “flower”-like agglomerates are formed. These β-PP samples with different morphologies show different pore generation ability after uniaxial tension. β-PP samples molded under 180 ℃ and 200 ℃ can form more microporous not only in quantity but also in quality. In contrast, there are no obvious pores generated for samples molded under 220℃ and 240℃.