Ballistic performance of epoxy composites reinforced with Amazon titica vine fibers

Abstract

Natural fiber-reinforced matrix polymer composites have shown great potential for engineering applications including ballistic protection. However, The Amazon region is full of natural fibers that have not yet been the fully studied and that might have important properties making them more attractive than synthetic fibers. This work presents a novel composite material consisting of titica vine fibers (Heteropsis flexuosa) reinforcing epoxy resin, for possible application in ballistic armor. Composite plates with different volumetric fractions of titica vine fibers (TVF) were subjected to a ballistic test, which consisted of firing multiple shots using .22 LR caliber ammunition. Through the results, it was possible to observe, with statistical validation by Weibull and ANOVA analyses, as well as the Tukey test, that a greater absorption of energy occurred for the conditions of 0 to 20 vol%, but with considerable loss of integrity. On the other hand, the 30 and 40 vol% samples have shown better integrity. In addition, the V L calculated for the samples with the highest percentage of fibers was lower than those found for the composites with 10 and 20 vol%. Thus, the higher the volumetric fraction of TVF, the lower the impact energy absorption capacity. This behavior corroborates the analysis by scanning electron microscopy (SEM) of the fracture surfaces of the composites after the ballistic test. For composites with less than 20 vol% TVF, brittle fractures evidences were observed, responsible for absorbing more impact energy. On the other hand, for other compositions, there was a predominance of complex mechanisms characteristic of ductile fracture, responsible for absorbing less energy, but still maintaining the integrity of the protection.