Biodegradable hybrid PLA composites incorporating coffee husks and mineral fillers

Abstract

This article details the development of hybrid composites with a PLA matrix filled with coffee husks, potassium feldspar, and Bahia Beige marble. Comprehensive analysis included FTIR, hardness, contact angle, density tests, SEM for microstructural insights, and XRF for optimizing raw material compositions. Also, variance analysis was applied in all results. The study revealed that these biodegradable composites hold promise for sustainable applications. Density variations were noted due to particle compaction, and hardness slightly decreased with coffee husks, attributed to uneven component distribution. Increased hydrophilicity was observed with filler addition. SEM confirmed strong interfacial adhesion, and color consistency was maintained. Notably, coffee husks significantly enhanced the degradation rate of PLA, achieving a 100% higher rate compared to pure PLA. The presence of calcium and potassium minerals offers additional benefits for soil health. The study suggests that thermoformed, multi-layered composite capsules can be fully biodegradable, promoting environmental sustainability in coffee capsule production.