Study on Mechanical Properties and Fracture Mechanisms of Lignin Fiber/epoxy Resin Composites

Lignin fiber/epoxy resin compositeused for energy absorbing was prepared by atmospheric stirring method. Quasi-static compressive mechanics tests were implemented by using the electronic universal mechanics tester (WDW-100KN) under ambient conditions to analyze the compressing behavior of the matrix material and composite at the strain rate of 10-2s-1 .Scanning electron microscope (SEM) was used to observe the microstructure of the composite after quasi-static compression damage. The results showed that when the ratio of epoxy resin and curing agent was 3:1, the internal structure of the matrix material was more uniform with smoother cross-section, which represented better mechanical properties. It was found that the addition of lignin fiber changed the compression characteristics of the matrix material, resulting in a strengthening stage appeared. At the same time, when the lignin fiber content was 2% or 3%, the composite could absorb more impact energy and delay crack generation, which met the performance requirement of energy absorbing materials.