Effects of Grafting Maleic Anhydride onto Poly‐ɛ‐caprolactone on Facilitative Enzymatic Hydrolysis

Abstract

Abstract Plastic waste is a global issue because it causes overflowing landfills and pollution, leading to environmental concerns. To address this crisis, materials that can be decomposed in the natural environment are introduced to replace conventional plastics. Poly‐ɛ‐caprolactone (PCL) is a commonly used plastic that can degrade in natural environments. However, owing to its hydrophobicity, its natural decomposition rate is low. In this study, PCL is modified with maleic anhydride (MA) (PCL‐g‐MA) to increase hydrophilicity and amorphous region for faster decomposition. To assess the hydrolysis in seawater, lipase hydrolysis is performed to compare the decomposition of PCL‐g‐MA and PCL. Consequently, in a Pseudomonas lipase‐containing PBS solution, it takes 72 and 120 h for complete hydrolyze of PCL‐g‐MA and PCL, respectively. MA grafted onto PCL increases the amorphous region, where lipase can easily diffuse into PCL‐g‐MA. Morphological (FESEM and POM images), thermal (TGA and DSC), and structural (FTIR, XRD, and XPS) analyzes support the hydrolysis reaction. The mechanisms proposed in this study confirm that lipase hydrolysis starts in the amorphous regions and then transfers to the crystal regions. This hydrolysis progress is expected to facilitate the creation of eco‐friendly low‐cost PCL‐g‐MA composites with high‐rate hydrolysis, such as bio‐plastics and bio‐fibers.

Keywords

• enzymatic hydrolysis
• grafting
• lipases
• maleic anhydride
• poly‐ɛ‐caprolactone