Characterization of polyester composites reinforced with natural fibers from Luffa cylindrica

Abstract

Concerns about global warming, environmental preservation, overexploitation of raw materials, and the development of new technologies are increasing. This has been attracting increasing interest in composites reinforced with natural fibers, mainly to replace synthetic materials. In this context, the present research work aimed to demonstrate the technical feasibility of the production of polyester-polymeric-matrix composites reinforced with fibers of Luffa cylindrica and a hybrid with fiberglass. The composites' physical properties (density, moisture content, water absorption, and thickness swelling) and mechanical properties (tensile, bending strength, and Rockwell hardness (RH)) were assessed. The composites were produced through cold pressing in a closed mold. The experiment was performed according to an entirely randomized design with two replicates per treatment and the means were compared by the Tukey test at 95% probability. The results demonstrated that the reinforcement with the Luffa fibers promoted a decrease in the density of the composites, with a minimum value of 1.01  g cm−3. In the assays of tensile strength, the reinforced composite presented a value of 10.20 MPa for this property, while for the bending strength, the value was 18.04 MPa. When the Luffa fibers were employed in the hybrid composite, the bending strength reached 105.12 MPa. In general, the composites reinforced with the plant fibers and the hybrid had physical and mechanical properties permitting their employment for several end-uses, according to the characteristics of each one. The new composites are partially biodegradable, sustainable, and light.