Biocatalyzed approach for the surface functionalization of poly(L‐lactic acid) films using hydrolytic enzymes. Issue 11 (3rd June 2015) - Pellis, Alessandro
Abstract: Poly(lactic acid) as a biodegradable thermoplastic polyester has received increasing attention. This renewable polyester has found applications in a wide range of products such as food packaging, textiles and biomedical devices. Its major drawbacks are poor toughness, slow degradation rate and lack of reactive side‐chain groups. An enzymatic process for the grafting of carboxylic acids onto the surface of poly(L‐lactic acid) (PLLA) films was developed using Candida antarctica lipase B as a catalyst. Enzymatic hydrolysis of the PLLA film using Humicola insolens cutinase in order to increase the number of hydroxyl and carboxylic groups on the outer polymer chains for grafting was also assessed and showed a change of water contact angle from 74.6 to 33.1° while the roughness and waviness were an order of magnitude higher in comparison to the blank. Surface functionalization was demonstrated using two different techniques, 14 C‐radiochemical analysis and X‐ray photoelectron spectroscopy (XPS) using 14 C‐butyric acid sodium salt and 4, 4, 4‐trifluorobutyric acid as model molecules, respectively. XPS analysis showed that 4, 4, 4‐trifluorobutyric acid was enzymatically coupled based on an increase of the fluor content from 0.19 to 0.40%. The presented 14 C‐radiochemical analyses are consistent with the XPS data indicating the potential of enzymatic functionalization in different reaction conditions. Abstract : Poly(lactic acid) as a biodegradable thermoplastic polyester has received increasing attention; however, its major drawbacks are poor toughness, slow degradation rate and lack of reactive side‐chain groups. The authors develop an enzymatic process for the grafting of carboxylic acids onto the surface of poly(L‐lactic acid) (PLLA) films using Candida antarctica lipase B as a catalyst. This is a novel green method for the modification of surfaces that can open new perspectives for the production of functionalized polyesters.