Lignocellulose coffee waste-based epoxy composites: effect of various treatment methods on composite properties

Abstract

Spent coffee waste (CW) was used as a reinforcement in the bisphenol A-type epoxy resin. Various methods such as alkali (NaOH), microwave (MW), ultrasound (US), and alkali pretreatment followed by microwave (NaOH-MW) treatments were applied for CW filler. For the characterization of CW, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) were used. The composites were characterized by SEM, mechanical, thermal, water sorption, and contact angle measurement analyses. The effects of treatment methods and filler ratios on the properties of epoxy composites were investigated. The highest tensile strength (81-106 MPa) for composites was found with NaOH-CW filler, while the highest decrease in thermal values was determined in the (NaOH + MW)-CW composites. Water sorption of composites which is affected by treatment methods of CW increased with filler loading in all composites. The best results were obtained for with MW-CW composites water absorption and wettability properties. [GRAPHICS]