Jhu Yu-Shan, Yang Teng-Chun, Hung Ke-Chang, Xu Jin-Wei, Wu Tung-Lin, Wu Jyh-Horng
Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan.
College of Technology and Master of Science in Computer Science, University of North America, Fairfax, VA 22033, USA.
Polymers (Basel). 2019 Jun 22;11(6):1078. doi: 10.3390/polym11061078.
The crystallization behavior of bamboo fiber (BF) reinforced polypropylene (PP) composites (BPCs) was investigated using a differential scanning calorimeter (DSC). The results showed that unmodified BF as a nucleation agent accelerated the crystallization rate of the PP matrix during cooling whereas there is no significant effect on the improved crystallization rate in BPCs with acetylated BFs. Based on the Avrami method, Avrami-Ozawa method, and Friedman method, the corresponding crystallization kinetics of PP reinforced with different acetylation levels of BFs were further analyzed. The results demonstrated that the crystal growth mechanism of the PP matrix for BPCs with unmodified and various acetylated BFs exhibited tabular crystal growth with heterogeneous nucleation. A higher cooling rate is required to achieve a certain relative crystallinity degree at the unit crystallization time for BPCs with a higher weight percent gain (WPG) of acetylated BFs (WPG >13%). Furthermore, based on the Friedman method, the lowest crystallization activation energy was observed for the BPCs with 19% WPG of acetylated BFs.
采用差示扫描量热仪（DSC）研究了竹纤维（BF）增强聚丙烯（PP）复合材料（BPCs）的结晶行为。结果表明，未改性的BF作为成核剂在冷却过程中加速了PP基体的结晶速率，而对乙酰化BF增强的BPCs的结晶速率提高没有显著影响。基于阿弗拉米法、阿弗拉米 - 小泽法和弗里德曼法，进一步分析了不同乙酰化水平BF增强PP的相应结晶动力学。结果表明，未改性和各种乙酰化BF增强的BPCs中PP基体的晶体生长机制表现为异相成核的片状晶体生长。对于乙酰化BF增重率（WPG）较高（WPG>13%）的BPCs，在单位结晶时间内达到一定相对结晶度需要更高的冷却速率。此外，基于弗里德曼法，观察到乙酰化BF的WPG为19%的BPCs的结晶活化能最低。
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