Confecção e caracterização mecânica de compósitos de matriz epoxídica reforçada com fibras de rami

Abstract

There has been growing interest in natural fiber reinforced polymer composites by the industry due to its low cost and good mechanical properties. A natural fiber that has a great potential for making polymer composites is the ramie fiber. The mechanical behavior of epoxy matrix composites reinforced with randomly oriented ramie fibers was investigated. In this study, tensile test and Izod impact were applied to specimens containing fiber mass fractions of 0%, 5%, 10% and 15%. The diameter and surface characteristics of the fiber bundle and the individual ramie fibers were identified by using an optical microscope. The fracture surfaces of each test were observed by using a camera. The ramie fibers were thin, with an average diameter of 48 ± 17 µm. The tensile strength of the composites increased by 28.2%, but with a loss of ductility around 76.4%. It was also observed that some tensile fractures occurred in bubbles, which were localized points of stress concentration. The Izod impact strength increased exponentially with the ramie fiber fraction, reaching an increase of 185.7% compared to pure thermoset. Therefore, it is possible to conclude that the ramie fiber is an excellent alternative for reinforced polymer composites.