This study assessed the properties of particleboard produced from the replacement of urea formaldehyde with cassava starch. Cassava starch (CS) and urea-formaldehyde (UF) were mixed at percentages of 100/0, 90/10, 70/30, 50/50, and 0/100, respectively. The mixture was added to the wood particles at 15% adhesive content based on the weight of oven-dried particles. Particleboards of sizes 20 mm × 300 mm × 300 mm and a targeted density of 600 kg m^–3 were manufactured by hot-pressing at 170 ^°C, compacting pressure 3.5 MPa for 8 min. Physical and mechanical properties (density, thickness swelling, water absorption, static bending, and hardness) were tested. The physical and mechanical properties also increased in the highest proportions of UF. Comparatively, manufactured with 50% CS + 50% UF, it performed better in all the evaluated properties. Thus, it could adopt the latter mixed ratio in the industry to reduce the quantity and cost of UF and its environmental emissions. The results obtained were adequate and in conformity with international standards. Hence, it could mix cassava starch and urea formaldehyde adhesives in different ratios to get desirable properties. It is possible to conclude that cassava starch could be considered a sustainable alternative adhesive.

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.