Mechanical properties and statistical analysis of polyester composite reinforced with miriti fibers braided using crochet technique

Abstract

This work presents an experimental investigation of the mechanical properties of composites reinforced with crocheted fabrics of miriti fibers (Mauritia flexuosa) in a polyester matrix. The fabrics were manufactured under different grammages, with and without alkaline fiber treatment. The composites were produced using two different viscosity conditions of the polyester matrix and part of these underwent post-cure treatment at 60 °C. In order to evaluate the effects of the input variables, the samples were produced by manual lamination with curing under vacuum, following a complete factorial experimental matrix type 24, tested according to the ASTM D 3039. The results showed that the variables alkaline treatment of the fibers and viscosity of the matrix presented statistically significant effects on the responses limit of tensile strength and modulus of elasticity. The highest level of tensile strength (13.02 MPa) was obtained in composites with alkaline treatment of the fibers, fabric grammage 473.9 g/cm2, matrix with higher viscosity and post-cure application, while the modulus of elasticity obtained the best performance (1.59 GPa) in samples without alkaline treatment of the fibers, manufactured with the fabric of lower grammage, with a more viscous matrix and that underwent post-curing.