Zhou Ting, Wang Meng, Chen Ning
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
Polymers (Basel). 2021 Jul 3;13(13):2204. doi: 10.3390/polym13132204.
Fiber-reinforced epoxy materials have the advantages of light weight, high strength and designability, which are widely used in high-technology fields. In this paper, triangular poly (vinyl alcohol) (PVA) fibers prepared by melt spinning were used for the first time in reinforcing and toughening epoxy resins. Based on intermolecular complexation and plasticization, the triangular PVA fibers were successfully prepared via melt spinning and hot drawing. The thermal properties, crystallinity, morphology and mechanical properties of the triangular fibers with different draw ratios were characterized by DSC, FTIR, XRD, SEM and tensile testing. The results show that the comprehensive performance of the triangular fibers increased with the increase in the draw ratio. The tensile strength of triangular fibers increased from 0.3 to 4.22 cN/dtex. Then, the triangular PVA fiber and circular PVA fiber-reinforced and toughened epoxy materials were prepared, respectively. The mechanical properties of triangular PVA fiber/epoxy composites were higher than that of circular fiber-reinforced and toughened epoxy materials. Furthermore, the single-fiber pull-out test was used to analyze the interface capability of fibers and epoxy. The pull-out force of the circular fiber was 1.24 N, while that of the triangular fiber was 2.64 N. The specific surface area of the triangular PVA fiber was larger than that of the circular PVA fiber, which better made its contact with epoxy and was not easily pulled out. Experiments prove that triangular PVA fiber is an ideal material for strengthening and toughening epoxy resin.
纤维增强环氧树脂材料具有重量轻、强度高和可设计性强等优点，被广泛应用于高科技领域。本文首次将通过熔融纺丝制备的三角形聚乙烯醇（PVA）纤维用于环氧树脂的增强增韧。基于分子间络合和增塑作用，通过熔融纺丝和热拉伸成功制备了三角形PVA纤维。采用差示扫描量热法（DSC）、傅里叶变换红外光谱法（FTIR）、X射线衍射法（XRD）、扫描电子显微镜（SEM）和拉伸试验对不同拉伸比的三角形纤维的热性能、结晶度、形态和力学性能进行了表征。结果表明，三角形纤维的综合性能随拉伸比的增加而提高。三角形纤维的拉伸强度从0.3 cN/dtex提高到4.22 cN/dtex。然后，分别制备了三角形PVA纤维和圆形PVA纤维增强增韧的环氧树脂材料。三角形PVA纤维/环氧树脂复合材料的力学性能高于圆形纤维增强增韧的环氧树脂材料。此外，采用单纤维拔出试验分析纤维与环氧树脂的界面性能。圆形纤维的拔出力为1.24 N，而三角形纤维的拔出力为2.64 N。三角形PVA纤维的比表面积大于圆形PVA纤维，使其与环氧树脂的接触更好，不易拔出。实验证明，三角形PVA纤维是环氧树脂增强增韧的理想材料。
