Obtenção e caracterização de compósitos biodegradáveis a partir de resíduos agroenergéticos

Abstract

The search for a new paradigm of preserving the environment and using natural products, has contributed to a greater interest in the use of materials derived from biomass. In this way, polymeric composites with vegetable fibers appear as an alternative in the field of materials for engineering applications. In this study, the main objective was to produce biodegradable composite materials from sugarcane straw and resin based on castor oil. The fibers were used in two sizes: 0 <fibers ≤4,27mm and 4,27 <fibers <10mm; resin in the proportion of 10%, 15% and 20%. The preparation method was carried out according to NBR 14810-2: 2018, using the compression molding technique at room temperature. Physical tests were carried out: moisture, density and swelling; mechanical tests: static bending, elasticity and compression. The morphological test was evaluated: scanning electron microscopy; and the composite biodegradability test, over a three-month period. The results showed that the values of the physical tests met the minimum limits established by the standard, resulting in 8,72% swelling of the composite material. In the mechanical test, the composite with less fiber and 20% resin was more resistant in the flexion test with a capacity of 3,69 N/mm², and in the compression test with 2,98 N/mm². To validate the results, the statistic was performed with significance at 5% by the F test, compared to the means by the Scott-knott test of the treatments performed. However, the performance of the smaller fiber composites was superior to the larger fiber composites, since the smaller fibers presented more compactness, in addition, the higher the percentage of resin used the more resistant the composite. The morphological analysis showed a wide interaction at the matrix/reinforcement interface. The biodegradation test showed that over the months the composites started to lose weight, which shows the improvement of the degradation. Therefore, the composite made of sugar cane straw and castor oil-based resin has great potential in the market, as it is developed from renewable sources, it is considered biodegradable and low cost in relation to composites produced from fibers synthetic.