Investigation on potential application of vegetable tanned leather wastes in biocomposite production

Polymer matrix composites are preferred in many industrial applications due to their advantages such as lightness, easy processing and good corrosion resistance, and "traditional" petrochemical polymers synthesized from fossil sources such as petroleum and natural gas are widely used in the production of many polymer-based materials. However, the synthesis and intensive use of such polymers cause a serious environmental burden. The use of traditional polymers, which are dependent on fossil resources, also raises concerns about ensuring sustainability with the effect of depleting oil reserves. Another important issue in industrial production is the reuse of wastes as secondary raw materials and providing added value, instead of disposal or storage within the scope of circular economy. For these purposes, the production of a new sustainable and environmentally friendly biocomposite was investigated within the scope of the thesis. Vegetable tanned leather shaving waste was used in the reinforcement phase of the biocomposites, and high-density biopolyethylene (BioPE) obtained from a renewable resource such as sugar cane was used in the matrix phase. In the literature BioPE was evaluated in the production of biocomposites with various reinforcement materials, to the best of the author's knowledge no previous research in the literature carried out regarding production of biocomposite reinforced with leather waste. From this point of view, this thesis focused on the reuse of an industrial waste and the production of a new environmentally friendly biocomposite using biopolymer. The matrix and reinforcing materials used in this study were mixed in various proportions by means of a thermo-kinetic mixer without adding any compatibilizer or binder chemicals, and then evaluated in the production of biocomposite using a hydraulic press with heating unit. The mechanical, thermal and morphological properties of the produced biocomposite samples were determined by tests and compared with similar studies in the literature. The results obtained from the thermal analyzes of biocomposites showed that the leather waste reinforcement increased the thermal stability of pure BioPE by shifting the degradation temperature and exhibited acceptable mass losses up to 200°C, making them suitable for composite production. The data obtained from the mechanical tests showed that the tensile strength and elongation at break values of composites decreased in comparison to the neat polymer, but improved modulus of elasticity, and increased impact strength at some concentrations.