Effects of melt structure on non‐isothermal crystallization behavior of isotactic polypropylene nucleated with α/β compounded nucleating agents |
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| Authors: | Qiyan Zhang Hongmei Peng Jian Kang Ya Cao Ming Xiang |
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| Affiliation: | 1. State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu, People's Republic of China;2. Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing, People's Republic of China;3. Chengdu Textile College, Chengdu, People's Republic of China |
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| Abstract: | In this study, the effects of melt structure (tuned by controlling the fusion temperature Tf) on non‐isothermal crystallization and subsequent melting behaviors of isotactic polypropylene (iPP) nucleated with α/β compounded nucleating agents (α/β‐CNAs) have been further investigated. The results show that under all cooling rates studied (2–40°C/min), the crystallization temperature on cooling curves increased gradually with decrease of Tf, meanwhile, when Tf was in temperature range of 166°C–179°C where ordered structures survived in the melt (defined as Region II), crystallization activation energy ΔE was found to be evidently lower compared with that when Tf > 179°C or Tf < 166°C. The results of subsequent heating showed that occurrence of Ordered Structure Effect can be observed at all the cooling rates studied; the location of the Region II was constant when cooling rate varied; Low cooling rate encouraged formation of more β‐phase triggered by ordered structure. Moreover, the role of ordered structure on β‐α recrystallization was comparatively studied by tuning the end temperature of recooling (Tend) after held at Tf, and it was found that ordered structure encouraged the formation of β‐phase with high thermal stability at low temperature part of Region II, while enhanced the β‐crystal with relatively low thermal stability at high temperature part of Region II. POLYM. ENG. SCI., 57:989–997, 2017. © 2016 Society of Plastics Engineers |
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