Solar energy tube processing of lemon residues for use as fillers in polyester-based green composites

In this study, we utilized a solar energy tube for the processing of lemon residues, which was used as a filler in polyester-based green composites. Lemon residues powder (LRP) was obtained by in-water grinding. We evaluated the biodegradability, morphology, and thermal and mechanical properties of composite materials made by melt-blending glycidyl methacrylate-grafted poly(butylene adipate-co-terephthalate) (PBAT-g-GMA) with coupling agent-treated lemon residues powder (TLRP). Composites containing PBAT-g-GMA and TLRP exhibited noticeably superior mechanical properties due to the significant compatibility between these two components. The dispersion of TLRP in the PBAT-g-GMA matrix was highly homogeneous as a result of ether formation between PBAT-g-GMA and TLRP and the consequent creation of branched and cross-linked macromolecules. Water resistance of PBAT-g-GMA/TLRP was greater than that of PBAT/LRP, although the weight loss of composites buried in soil compost indicated that both were biodegradable, even at high levels of LRP or TLRP substitution. The PBAT-g-GMA/TLRP membranes were more biodegradable than those made of PBAT, implying a strong connection between these characteristics and biodegradability.