Abstract

In this study, four types of widely used commercial β-nucleating agents (β-NAs) were used to prepare β-nucleated isotactic polypropylene (β-iPP). Differential scanning calorimetry (DSC), polarizing optical microscopy (PLOM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were used to comparatively study the roles of β-NA in the β-nucleation efficiency, isothermal crystallization kinetics and crystalline morphology of the samples. Results revealed that the geometric shapes and thermal stabilities of the β-NAs are quite different from each other, moreover, the β-nucleation efficiencies (β-NE) of the β-NAs are quite different. The β-NE of NAB83 and PACA are very high, while those of TMB-5 and WBG‑II are relatively low. The critical concentrations of the β-NAs were obtained as follows: NAB83 = 0.02 wt %, PACA = 0.02 wt %, TMB-5 = 0.15 wt %, WBG = 0.3 wt %. Morphological studies of SEM and PLOM indicated that for different β-NAs, the β-phase fraction, crystalline sizes and morphology of the formed β-phase are quite different. Isothermal crystallization kinetics provided detailed kinetic information on the different β-NAs.

中文翻译：

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β-成核剂在全同立构聚丙烯结晶和多晶行为中的作用研究

摘要

在这项研究中，使用四种类型的广泛使用的商业化β-成核剂（β-NAs）来制备β-成核的等规聚丙烯（β-iPP）。使用差示扫描量热法（DSC），偏振光学显微镜（PLOM），扫描电子显微镜（SEM）和热重分析（TGA）来比较研究β-NA在β成核效率，等温结晶动力学和晶体形态中的作用样本。结果表明，β-NAs的几何形状和热稳定性存在很大差异，此外，β- NAs的β-成核效率（β- NE）也存在很大差异。β- NENAB83和PACA的系数非常高，而TMB-5和WBG‑II的系数却相对较低。β-NA的临界浓度如下获得：NAB83 ＝ 0.02重量％，PACA ＝ 0.02重量％，TMB-5 ＝ 0.15重量％，WBG ＝ 0.3重量％。SEM和PLOM的形态学研究表明，对于不同的β-NA，β相分数，形成的β相的晶体大小和形态有很大不同。等温结晶动力学提供了有关不同β-NA的详细动力学信息。