摘要
用高分辨电子显微学方法对从极稀的二甲苯溶液中得到的纳米级聚乙烯 ( PE)和聚丙烯 ( PP)微晶进行了研究 ,发现这种纳米级微晶是分子堆砌不完善 ,但可以独立存在的一种亚稳态结构 ,其晶格存在着大量的弯曲、分叉、位错等缺陷 ,经热处理后有序程度大大提高 .表明高分辨电子显微学方法是研究 PE和 PP纳米级微晶的亚稳态结构和稳定性的有效手段 .
When polymer crystallized from its dilute solution, the formation of small crystallites is difficult because of the balance between the favorable energy decrease as the more stable crystal formed and the unfavorable interface energy increasing with the forming of crystallites, thus the crystallites smaller than a minimum critical size are unstable and will be disappear or grow to larger size crystals. In this paper, High Resolution Transmission Electron Microscopy(HRTEM) technology was used in the study of polyethylene(PE) and polypropylene(PP) nano-sized crystals obtained from their dilute solution of xylene. The results showed that the molecular packing in these crystals was far from perfect one. There were many defects such as distortion, branches, and dislocation in the crystals. After isothermal crystallization at the temperature of 413 K, the crystallinity was improved greatly. All these proved that the high resolution transmission electron microscopy technique was very powerful in the study on polymer crystal at the level of molecules, and the nano-sized crystals were another stable crystal state of PE and PP.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2004年第4期766-769,共4页
Chemical Journal of Chinese Universities
基金
国家自然科学基金 (批准号 :2 0 1740 43 )
国家重点基础研究发展规划项目 (批准号 :G19990 64 80 5 )资助
