Abiotic Degradation Technologies to Promote Bio-Valorization of Bioplastics

Biodegradable bioplastics have emerged as a promising sustainable alternative to minimize the environmental impact of traditional plastics. Nevertheless, many of them degrade slowly under natural or industrial conditions, raising concerns about their practical biodegradability. This fact is related to the high-order structure of the polymer backbones, i.e., high molar mass and high crystallinity. Research efforts are being devoted to the development of technologies capable of reducing the length of polymer segments by accelerated chain scission, which could help improve biodegradation rates upon disposal of bioplastic products. The objective of this review is to examine the current state of the art of abiotic degradation techniques, physically driven by temperature, mechanical stress, UV/gamma/microwave irradiation, or plasma or dielectric barrier discharge, and chemically induced by ozone, water, or acidic/basic solutions, with the aim of enhancing the subsequent biodegradation of bioplastics in controlled valorization scenarios such as composting and anaerobic digestors. Particular attention is given to pretreatment degradation technologies that modify surface properties to enhance microbial adhesion and enzymatic activity. Technologies such as ozonation and plasma-driven treatments increase surface hydrophilicity and introduce functional groups with oxygen bonds, facilitating subsequent microbial colonization and biodegradation. Irradiation-based techniques directly alter the chemical bonds at the polymer surface, promoting the formation of free radicals, chain scission, and crosslinking, thereby modifying the polymer structure. Pretreatments involving immersion in aqueous solutions may induce solution sorption and diffusion, together with hydrolytic chain breakage in bulk, with a relevant contribution to the ulterior biodegradation performance. By promoting abiotic degradation and increasing the accessibility of biopolymers to microbial systems, these pretreatment strategies can offer effective tools to enhance biodegradation and, therefore, the end-of-life management of bioplastics, supporting the transition toward sustainable cradle-to-cradle pathways within a biocircular economy.