Toward sustainable PLA films by replacing chloroform for the green solvent dimethyl carbonate

Biodegradable polymers and advanced recycling methods are being researched to address the pressing issues of plastic waste and environmental degradation. Green Chemistry, a discipline prioritizing contamination prevention, plays a crucial role in developing sustainable practices. This research focuses on the substitution of chloroform, a traditional solvent, with dimethyl carbonate (DMC), a green solvent, for the fabrication of polylactic acid (PLA) films using solvent casting methodology. The suitability of DMC was assessed by comparing the physicochemical properties of films of amorphous (a-PLA) and semicrystalline (c-PLA) prepared on glass and silicone substrates. DSC revealed differences in glass transition temperature and crystallinity between films cast with different solvents and substrates. XRD indicated that c-PLA films crystallized in the α phase, with variations in crystal size, lattice parameters, and spatial arrangement depending on the substrate and solvent. Contact angle measurements revealed that c-PLA films on silicone exhibited significantly higher hydrophobicity compared to those on glass, which may be attributed to the outward orientation of non-polar groups influencing hydrophobic behavior. AFM showed that c-PLA films cast with DMC on glass had the highest surface roughness. These findings underscore the importance of solvent choice in the structural and surface properties of PLA films and their environmental impact, highlighting the potential of DMC as a sustainable alternative to traditional solvents. The results suggest that using DMC not only improves the physicochemical properties of PLA films but also promotes environmentally friendly practices in polymer fabrication, paving the way for more sustainable material development in various industrial applications.