Does the Layer Configuration of Loofah (Luffa cylindrica) Affect the Mechanical Properties of Polymeric Composites?

Abstract

The arrangement of layers of natural long fibers that compose a polymeric composite can result in a final material with greater mechanical strength, in addition to replacing synthetic glass and carbon fibers. This study proposed different configurations of layers of loofah fibers (Luffa cylindrica) to produce reinforced polymeric–polyester composites, determining their potential mechanical properties such as flexural strength and Rockwell hardness. The layers were arranged by varying parallel and perpendicularly the direction of the loofah fibers pieces. The reinforcement decreased the density of all composites, with the lowest value, 1.03 g cm−3, indicated by the configuration 90°/0°/90°. The composites in the configuration 0°/90°/0° presented the highest value among the reinforced compositions (10.8 MPa), in addition to the highest rigidity value during bending tests (774.8 MPa). In the Rockwell hardness tests, the treatment reinforced with fibers in the configuration 90°/90°/90° had the highest value among all experimental treatments with a value of 86.9 HHR. The configuration angle of the loofah layers has a significant impact on the mechanical performance of the composites and should be taken into account in their confection. Furthermore, composites reinforced with loofah fibers in different configurations have physical–mechanical properties that qualify them for non-structural applications in indoor environments.