Development of polymeric composites reinforced with buriti leaf fiber

ABSTRACT

The objective of this research was to study the viability, with respect to tensile strength, of using buriti leaf as reinforcement in composites with unidirectional continuous fibers in polymeric matrix. As matrix, isophthalic polyester, orthophthalic polyester and epoxy resins were used. The tensile strength of fiber, resins and composites confectioned with each polymer was analyzed. Pullout tests were performed to verify fiber adhesion with the resins used as matrix. The fiber was characterized by optical microscopy and using a scanning electron microscope (SEM) in addition to determining its density. Regarding the structure, it was observed that the fibers have a central gap between the adaxial and abaxial faces and that there is a winding of the fiber. The pullout tests showed that there was greater adhesion between the buriti leaf fiber and the epoxy matrix, with a critical length lc = 1.0 mm, followed by the isophthalic polyester matrix, with lc = 2.8 mm, and the matrix of orthophthalic polyester with lc = 26.8 mm. The fiber presented tensile strength ranging from 100.8 MPa to 224.1 MPa. It was found that the tensile strength of the fibers is higher for smaller diameters. Among the resins studied, epoxy showed the highest average tensile strength (60.5 MPa), followed by isophthalic polyester (34.5 MPa) and orthophthalic polyester (27.7 MPa). Tests with the composites created showed that the epoxy matrix is the most promising as tensile strength, followed by the isophthalic polyester matrix. The orthophthalic polyester matrix presented resistance values much below the others. It was concluded that the buriti leaf fiber presented a good potential for the production of light and resistant composites.

Keywords
Pullout test; Tensile strength; Density; Polymeric matrix; Vegetable fiber