Waste not, want not: The use of leather waste in flame retarded EVA

• Published in: Materials & design Vol. 210; p. 110100
• Main Authors: Battig, A., Sanchez-Olivares, G., Rockel, D., Maldonado-Santoyo, M., Schartel, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.11.2021; Elsevier
• Subjects: Charring; EVA; Fire protection; Flame retardancy; Leather waste; Tannery industry; Tannery industry; Leather waste; EVA; Flame retardancy; Fire protection; Charring
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2021.110100

[Display omitted] •Wastes from leather production are upcycled as sustainable fillers for polymer composites.•Leather waste is an adjuvant and synergist to phosphorus flame retardants that decrease the fire load of poly(ethylene–vinyl acetate).•The main modes of action, which include enhanced residue formation and stabilization, are explored and characterized multi-methodically.•The combination of flame retardant and filler exhibit better fire performance than equal loadings of only flame retardant.•The chemical mechanisms of flame retardancy are elucidated to explain the fire phenomena. Leather is among the most ancient, widely used materials worldwide. Industrial-scale leather production produces large quantities of organic waste attained during shaving and buffing steps during processing. In this study, leather wastes (LW) are used as fillers in flame retarded polymer composites. LW is investigated as a multifunctional bio-filler that enhances the fire performance of flame retarded poly(ethylene–vinyl acetate) (EVA) containing phosphorus flame retardants (P-FRs) ammonium polyphosphate (APP) or a melamine-encapsulated APP (eAPP). Using LW from tanneries as adjuvants to enhance P-FRs in EVA reduces industrial wastes that otherwise require costly waste management solutions. Materials are characterized multi-methodically via mechanical tests, electron microscopy, rheology, thermogravimetric analysis, evolved gas analysis, and condensed phase FTIR, also reaction-to-small-flames and cone calorimeter tests. EVA containing 10 wt-% LW and 20 wt-% P-FRs achieve 20% reductions in fire loads versus EVA, and up to 10% reduction in effective heats of combustion versus EVA with equal (30 wt-%) P-FR loadings. Enhanced char stabilization of EVA composites with LW and P-FRs lowered peaks of heat release rates up to 53% compared to EVA, and up to 40% compared to equal P-FRs loadings. Synergisms between LW and P-FRs in EVA are quantified. A chemical decomposition mechanism is proposed.