Biodegradation behavior of poly (lactic acid) samples obtained by three‐dimensional printing: Influence of temperature and pigment presence

Abstract

In this study, the biodegradation behavior in the soil of natural and pigmented poly (lactic acid) (PLA) plates obtained by three‐dimensional (3D) printing or by compression molding was evaluated by the respirometry method at three different temperatures: 21, 28, and 35°C. PLA samples before and after aerobic biodegradation tests were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TG), and size exclusion chromatography analysis. The increase in test temperature enhanced the biodegradation process. At a test temperature of 35°C, the maximum biodegradation rates of natural PLA and pigmented PLA were 65% and 68% higher, respectively, compared to the maximum biodegradation rate observed at 21°C. DSC and TG analysis indicate that pigmented PLA samples were more susceptible to degradation by hydrolysis. However, the rate of biodegradation efficiency was lower in pigmented PLA samples, with a decrease of 16%, 24%, and 14% at 21, 28, and 35°C, respectively, compared to natural PLA. This behavior indicated that pigment hindered the hydrolysis by‐products absorption by microorganisms. Additionally, the presence of micro voids in PLA samples obtained through 3D printing accelerated the rate of biodegradation efficiency by 32% at 28°C compared to pressed samples.Highlights Poly (lactic acid) (PLA) plate biodegradation in soil was analyzed using respirometry method. Temperature, pigment presence, and sample preparation method were considered. Higher temperatures enhanced both natural and pigmented PLA biodegradation. Pigments appeared to act as antimicrobial agents, slowing down the process. Water presence in the micro voids accelerated hydrolysis and biodegradation.