Photochemical degradation of PLA-based green composites containing waste biomass from Posidonia oceanica, Chamaerops humilis and Ailanthus altissima: A comparative study

Abstract

The photochemical degradability of PLA-based composites containing three different natural fillers, namely Posidonia oceanica (PO), Chamaerops humilis (CH), and Ailanthus altissima (AA), was evaluated to understand how the morphological and physicochemical features of these composite systems affect their durability. Composites containing 10% or 20% of filler were prepared by melt-processing and subjected to accelerated weathering involving UV irradiation and condensation cycles. The materials were thoroughly characterized, and the evolution of morphological, physicochemical, and mechanical properties was monitored upon aging time. The results demonstrate the significant impact of filler type on the photochemical stability of PLA-based composites. PO and CH fillers, with high porosity, resulted in less compact composites that underwent rapid hydrolytic degradation, experiencing surface and bulk erosion. AA composites exhibited the highest durability, with their dense morphology effectively delaying degradation. Overall, composites with 10% PO and 20% CH had the lowest stability (less than 6 h), the other PO- and CH-series materials retained durability for 24-30 h, similar to neat PLA, while AA-series composites proved to retain their mechanical properties for up to 36 h.