Preparation of antimicrobial and biodegradable hybrid soybean oil and poly (L-lactide) based polymer with quaternized ammonium salt

Abstract

The novel hybrid quaternized soybean oil (SBO) and poly (L-lactide) (PLA) based polymer (QAS-SBO-PLA) is synthesized by sequential ring-opening polymerization (ROP) and nucleophilic substitution reaction. In this purpose, oxirane rings of epoxidized soybean oil (ESBO) firstly are modified to chlorine and hydroxyl functionalities by utilizing hydrochloric acid (Cl-SBO-OH). The obtained CI-SBO-OH is used as macroinitiator for the ROP of L-lactide monomer in the presence of stannous octoate as a catalyst in order to attain the SBO main chain possessing chlorine and PLA pendant groups (Cl-SBO-PLA). Finally, Cl-SBO-PLA is quaternized by triethyl amine to achieve the corresponding material QAS-SBO-PLA. Structural analysis of QAS-SBO-PLA is performed by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (H-1 NMR) spectroscopies, and gel permeation chromatography (GPC) as well, whereas wettability and thermal properties are determined by water contact angle (WCA) measurement, thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses, respectively. Antimicrobial activity of QAS-SBO-PLA against to gram positive Staphylococcus aureus (S. aureus) and gram negative E. coli (E. coli) bacteria is investigated by agar diffusion method. Moreover, hydrolytic and enzymatic biodegradation behavior of QAS-SBO-PLA is monitored for 30 days in the presence or absence of lipase enzyme. The results of the present study indicate that QAS-SBO-PLA achieved has higher inhibition effect against to S. aureus than E. coli. Furthermore, approximately 44% of QAS-SBO-PLA by weight is degraded in the enzymatic medium, while this degradation percentage found to be 12% for hydrolytic medium in 30 days. It is thus estimated that this facile synthesis method for QAS-SBO-PLA with good antimicrobial and biodegradation abilities will provide beneficial insights to investigators working on biomedical applications. (C) 2020 Elsevier Ltd. All rights reserved.