含缩醛结构环氧树脂的固化行为及其碳纤维复合材料的制备与性能

Curing behavior of epoxy resin with acetal structure and preparation and properties of its carbon fiber composites

针对含缩醛结构生物基环氧树脂体系的工艺性能开展研究,采用旋转流变仪和非等温DSC对缩醛环氧树脂体系的流变性能和固化行为进行了分析,确定了其注胶温度约为40℃。采用自催化模型结合n级模型的分段模型获得其固化动力学参数,分段模型拟合得到的曲线与实验曲线吻合较好,表明该模型在2.5~20 K/min的升温速率下能较好地描述含缩醛结构环氧树脂体系的固化反应过程。通过外推法确定了树脂体系的优化固化工艺条件,制备出的含缩醛结构环氧树脂的拉伸强度和弯曲强度分别为79 MPa和130 MPa。进一步研究了碳纤维与环氧树脂之间的界面粘结性能和力学性能,发现碳纤维/缩醛环氧树脂复合材料的界面剪切强度和力学性能与碳纤维/商用环氧树脂复合材料的基本相当,表明可降解的缩醛环氧树脂可以替代商用环氧树脂,具有广泛的应用前景。另外,碳纤维/缩醛环氧树脂复合材料具有较好的降解性能,回收碳纤维的单丝拉伸强度与原始碳纤维的相当,可以有效回收高质量的碳纤维。

To investigate the forming process of bio-based epoxy resin system with acetal structure,the rheological properties and curing behavior of the epoxy resin system with acetal structure were studied by rotating rheometer and non-isothermal DsC.The glue injecting temperature is determined to be about 4oC.The curing kinetic parameters were obtained by the piecewise model combining the autocatalytic model and the n-order model.The fitting curves from the piecewise model are in good agreement with the experimental curves,indicating that the model can accurately describe the curing reaction process of epoxy resin system with acetal structure at the heating rates of 2.5-20 K/min.The curing procedure of the resin system was determined by an extrapolation method.The tensile strength and bending strength of the epoxy resin with acetal structure are 79 MPa and 130 MPa,respectively.It is found that the interfacial shear strength(IFSS)and interlaminar shear strength(ILSS)of carbon fiber/acetal epoxy resin composites are similar to those of carbon fiber/commercial epoxy resin composites,indicating that the interfacial bonding property between acetal epoxy resin and carbon fiber is similar to that of commercial epoxy resin.In addition,the tensile and flexural properties of the two composites are similar,indicating that the degradable acetal epoxy resin may replace the commercial epoxy resin and give potential competitive advantages over the applications.In addition,the carbon fiber/acetal epoxy resin composites have good degradation performance,and the single fiber tensile strength of the recovered carbon fiber is comparable to that of the original carbon fiber,indicating that high-quality carbon fiber can be effectively recycled.