Fabrication of Novel Polymer Composites from Leather Waste Fibers and Recycled Poly(Ethylene-Vinyl-Acetate) for Value-Added Products

Abstract

This investigation was focused on evaluating the utilization of Leather-waste, i.e., “Leather Shavings”, to develop “Poly(ethylene-vinyl-acetate)” (EVA) based “polymer matrix composites”. Composites with the highest ratio of 1:1 were developed using a rolling-mill, which was then subjected to hot-press molding for value-added applications, notably in the “floor-covering”, “structural”, “footwear”, and “transportation domain”. The specimens were examined for evaluating the “physico-mechanical characteristics” such as, “Compressive and Tensile, strength, Abrasion-resistance, Density, tear-resistance, hardness, adhesion-strength, compression, and resilience, damping, and water absorption” as per standard advanced testing techniques. Raising the leather-fiber fraction in the composites culminated in considerable enhancement in “physico-mechanical characteristics” including “modulus”, and a decline in “tensile-strain” at “fracture-breakage”. The thermo-analytic methods, viz. TGA and DSC studies have evidenced that substantial enhancement of thermo-stability (up to 211.1–213.81 °C) has been observed in the newly developed PMCs. Additionally, the DSC study showed that solid leather fibers lose water at an endothermic transition temperature of around 100 °C, are thermo-stable at around 211 degrees centigrade, and begin to degrade at 332.56-degree centigrade for neat recycled EVA samples and begin to degrade collagen at 318.47-degree centigrade for “leather shavings/recycled EVA polymer composite samples”, respectively. Additionally, the “glass transition temperature” (Tg) of the manufactured composites was determined to be between −16 and 30 °C. Furthermore, SEM and EDAX analysis have been used to investigate the morphological characteristics of the developed composites. Micrograph outcomes have confirmed the excellent “uniformity, compatibility, stability and better-bonding” of leather-fibers within the base matrix. Additionally, the “Attenuated-total-reflection” (ATR-FTIR) was carried out to test the “physicochemical chemical-bonding”, “molecular-structure”, and “functional-groups” of the “base matrix”, and its “composites” further affirm the “recycled EVA matrix” contained additives remain within the polymeric-matrix. An “X-ray diffraction study” was also conducted to identify the “chemical-constituents” or “phases” involved throughout the “crystal-structures” of the base matrix and PMCs. Additionally, AFM analysis has also been utilized to explore the “interfacial adhesion properties” of mechanically tested specimens of fabricated polymeric composite surfaces, their “surface topography mapping”, and “phase-imaging analysis” of polymer composites that have leather-shavings fibers.