Development and Mechanical Characterization of Tea Fiber Residue/Hazelnut Shell-based Sustainable Biocomposites

Abstract

Biocomposites are environmentally friendly and biodegradable materials produced from renewable resources or agricultural residue. In this study, biocomposite boards were produced using tea fiber residue and hazelnut shell. These boards were designed to degrade naturally and mix into the soil within 2 years, depending on climatic conditions, without causing environmental pollution. Test sheets were produced from the raw materials using urea-formaldehyde glue as a binder, and diammonium phosphate fertilizer was used to regulate the decomposition time and nutrient contribution. A total of 32 groups of boards were produced with different raw material ratios. The boards were 6 and 10 mm thick, and bending and tensile strength tests were performed to determine their mechanical performance. The highest bending strength was measured at 3.96 N/mm² in the 10 mm thick board containing 89% tea fiber residue, 5% diammonium phosphate, and 6% adhesive. The lowest bending strength was obtained in the board containing 41% walnut shell, 41% tea fiber residue, 15% phosphate, and 3% glue, with a value of 0.58 N/mm². In tensile tests, the highest value obtained was 0.48 N/mm² in a board containing 84% tea fiber residue, 10% phosphate, and 6% adhesive; while the lowest value was 0.06 N/mm² in a board containing 44.5% walnut shell, 44.5% tea fiber, 5% diammonium phosphate, and 10% adhesive.