Study on Mechanical and Thermal Properties of Amazon Fibers on the Polymeric Biocomposites: Malva and Tucum

Amazon region found abundant vegetal fibers with diversified properties to the application. Tucum and malva fibers regularly obtained in this region were applied as reinforcement in the polymeric biomatrix and as a substitute for synthetic materials. Castor oil was used as the polyol to prepare the polyurethane biomatrix (PU). Amazon fibers were incorporated in this biomatrix using high proportions (30, 50, and 70 wt.%; 30 mm length), TPU (tucum polyurethane composite), and MPU (malva polyurethane composite). This study valorized regional materials and substituted synthetic products by renewable source materials. The fibers’ characterization results showed a high cellulose percentage, promoting high crystallinity values by XRD (X-ray diffraction) results (67.5 % for malva and 60.0 % for tucum). SEM (Scanning Electron Microscopy) images revealed the arrangement/thickness of the fibers, as well as the composite morphology. Thermolysis and mechanical properties investigate the composites in which the natural fibers were incorporated into the polyurethane matrix in large percentages, maintaining the main properties. The composites presented high impact Izod values, as 550 J m−1 for TPU-70 wt.% and 452 J m−1 for MPU-70 wt.%. In general, composites prepared with a high content of natural products from renewable sources showed promising performances in the applied tests, with excellent potential for replacing engineering materials.