Yu Yansong, Xu Ruizhang, Chen Jinyao, Kang Jian, Xiang Ming, Li Yuanjie, Li Lu, Sheng Xingyue
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University Chengdu 610065 China
Central Research Academy of Dongfang Electric Corporation Chengdu 611731 China
RSC Adv. 2019 Jun 24;9(34):19630-19640. doi: 10.1039/c9ra03416a. eCollection 2019 Jun 19.
In this paper, the influence of ordered structure effects (OSE) on crystallization behaviors of β-nucleated isotactic polypropylene/graphene oxide (β-iPP/GO) composites with different thermal histories, which crystallized at a slow cooling rate (called SLOW), fast cooling rate (called FAST) and medium cooling rate (called MED), respectively, was studied by differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The ordered structure status of three samples before crystallization measurement was controlled by tuning the fusion temperature and melting time . The results showed that for all samples, OSE would occur in an appropriate region (Region II). The OSE efficiency of MED was the highest, while that of SLOW were the lowest. It was also found that the crystallinity and crystalline perfection of SLOW were the highest, while those of FAST were the lowest. The effects of the melting time on the OSE were also investigated. At = 172 °C, the OSE efficiency of FAST reached the maximum at = 5 min, while that of SLOW reached the maximum at = 20 min. It was indicated that the OSE efficiency was affected by thermal history, and it could be improved by selecting the appropriate . Related mechanisms concerning the roles of thermal history on the OSE behavior were proposed based on the results of DSC and SAXS.
本文采用差示扫描量热法（DSC）和广角X射线衍射法（WAXD），研究了有序结构效应（OSE）对不同热历史的β晶型全同立构聚丙烯/氧化石墨烯（β-iPP/GO）复合材料结晶行为的影响，这些复合材料分别以慢速冷却速率（称为SLOW）、快速冷却速率（称为FAST）和中速冷却速率（称为MED）进行结晶。通过调节熔融温度和熔融时间来控制三个样品在结晶测量前的有序结构状态。结果表明，对于所有样品，OSE会在适当的区域（区域II）出现。MED的OSE效率最高，而SLOW的OSE效率最低。还发现SLOW的结晶度和结晶完善程度最高，而FAST的结晶度和结晶完善程度最低。还研究了熔融时间对OSE的影响。在 = 172 °C时，FAST的OSE效率在 = 5分钟时达到最大值，而SLOW的OSE效率在 = 20分钟时达到最大值。结果表明，OSE效率受热历史影响，可以通过选择合适的来提高。基于DSC和SAXS的结果，提出了关于热历史对OSE行为作用的相关机制。
