Annealing effect on crystalline structure and mechanical properties in long glass fiber reinforced polyamide 66 |
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| Authors: | Qingyu Meng Yizhuo Gu Liang Luo Shaokai Wang Min Li Zuoguang Zhang |
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| Affiliation: | 1. Key Laboratory of Aerospace Advanced Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing, China;2. Unmanned Systems Research Institute, Beihang University, Beijing, China |
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| Abstract: | Generally, annealing is one of the important post‐processing methods used to obtain injection molding products coupled with excellent comprehensive performance. Based on a series of experimental studies in this work, a systematic investigation was performed to research the annealing effect on crystalline structure and mechanical properties in long glass fiber reinforced polyamide 66 (LGF‐PA66) composite. The composite was prepared by injection molding, using LGF‐PA66 pellet with 50 wt % fiber content and 12 mm length. Composite samples were annealed in 120 °C to 200 °C range and then subjected to various tests at room temperature. Besides, the releasing strain during a specific temperature cycle was also investigated. Our results suggest that annealing treatment had a neglected impact on the crystallinity and crystal morphology of LGF‐PA66 composite. However, with the increasing of processing temperature, annealing could strikingly promote the phase transition from γ to α and the further growth of α2 crystal in (010)/(110). In addition, annealing of LGF‐PA66 composite resulted in a drastic increase in tensile and flexural properties and a reduction in impact strength, along with the transition of failure mode. The changes in mechanical properties were attributed to the crystal transition, strengthening of matrix performance, and the release of residual stress. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44832. |
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| Keywords: | composites crystallization mechanical properties thermoplastics |
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