• Kandasami, Asokan
• Dave, Foram
• Jacob, Josemon
• Tormey, David
• Mcafee, Marion

Abstract

<p>Polylactide, PLA (also called Polylactic acid) is an aliphatic polyester that exhibits a slow rate of biodegradation due to its non-polar nature. In this study, it is demonstrated that gamma rays enhance the biodegradability of PLA. The pristine PLA samples were irradiated by gamma rays with various doses: i.e., 25, 50, 75, and 100 kGy. These irradiated samples were analyzed by the Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), and contact angle measurements to understand the functionalization of this polymer. While the FTIR analysis shows the emergence of a new band at 3400-3600 cm-1 corresponding to -OH groups in alcohols, hydroperoxides, and carboxylic acids, the TGA results exhibit a change from a single step to a two-step degradation pathways upon γ-rays irradiation which is attributable to the formation of polar -OH groups. The DSC results indicate a decrease in Tg due to the decrease in the molecular weight after γ-rays irradiation which is also consistent with the results from the gel permeation chromatography. The decrease in the contact angles of the γ-rays irradiated samples provides evidence for hydroxyl functionalization. This study shows that γ-rays irradiation enhances the biodegradability of PLA.</p>

Topics

• impedance spectroscopy
• polymer
• thermogravimetry
• differential scanning calorimetry
• molecular weight
• functionalization
• Fourier transform infrared spectroscopy
• alcohol
• carboxylic acid
• gel filtration chromatography