Abiotic Degradation and Composting Behavior of 3D-Printed PLA and PLA/Wood Biocomposites

The use of 3D printing technology is growing due to its ease of use, accessibility, and potential to produce complex and functional products. In the construction and building industries, 3D printing is used to produce intricate enclosures, building components, furniture designs, and household items. However, the accessibility of this technology is accompanied by the generation of polymeric residues, especially poly(lactic acid) (PLA), which is also prone to abiotic degradation. In this context, the present work aims to analyze the abiotic degradation and composting behavior of 3D-printed PLA and its wood biocomposite. The printed materials were subjected to accelerated weathering and characterized in terms of their physical and mechanical properties, as well as their surface chemical changes via FTIR. Additionally, disintegration and mineralization under composting conditions were evaluated, including a preliminary assessment of microplastics generation. The results showed that, as expected, the initial porosity was higher in the biocomposite (12.5%) than in the neat PLA (7.5%); however, after weathering, it increased to 13.2% in the pure biopolymer, while the biocomposite remained almost unaffected. This behavior is attributed to the wood particles, which inhibited the hydrolysis of PLA under weathering and water immersion. The wood particles also reduced microplastics generation without affecting the ultimate biodegradation, with calculated maximum mineralization values of approximately 75%.