Changes in the thermal and structural properties of polylactide and its composites during a long-term degradation process

Abstract

As a polymer degrades, its structure changes, and the course of composting also affects the rate and degree of decomposition. Moreover, the potential exists for the formation of microplastics. This work focuses on the investigation of the long-term hydrolytic degradation of PLA-based composites at different temperatures (50, 55, and 60 °C, respectively). Samples were prepared on semi-industrial equipment, simulating actual production conditions. The effect of the degradation temperature on molecular weight was studied by gel permeation chromatography. Variation in the thermal properties and crystallinity of the PLA and its composites was investigated using differential scanning calorimetry and thermal gravimetric analysis. Mass loss during hydrolytic degradation was assessed using the gravimetric technique, and confirmation of microplastic residues in the hydrolyzed samples was evaluated using Fourier-transform infrared spectroscopy.