Synthesis of Epoxy Resin From Linseed Oil and Development of New Bio-Based Films Using Calendula Officinalis L. Oil

Abstract

Epoxy resin thin films are widely used in applications such as anticorrosive coating materials, insulating and electronic packaging films, and adhesives; accordingly, research on new epoxy materials has become increasingly important. Developing new bio-based epoxy films or coatings is important to address this issue. This study synthesized epoxidized linseed oil (ELO) by epoxidation of linseed oil, and a novel bio-based matrix was formed with commercial epoxy resin (ER) at a weight ratio of 3:2. The characterization of ELO was performed using Fourier Transform Infrared Spectroscopy (FTIR), as well as by determining the iodine and epoxide groups. In addition, new films were formed by adding 1 %, 3 %, 5 %, 7 %, 10 %, and 15 % by weight Calendula officinalis L. oil (CldO). The effect of CldO on mechanical (thickness, tensile strength, and elongation at break), structural (Scanning Electron Microscopy (SEM) and FTIR), water barrier (WVP, water solubility, swelling), chemical resistance, antibacterial, and biodegradation properties was evaluated. ELO and CldO reduced the film's thickness. The film's water vapor permeability ratio (WVTR) was relatively low, ranging from 0.0153 g/(m2 center dot d) to 0.0661 g/(m2 center dot d). A 10 wt% CldO was selected as an appropriate ratio, especially regarding mechanical properties, water vapor permeability rate (WVPR), and opacity. Above 10 wt% CldO, tensile elongation sharply decreased, while water solubility and opacity significantly increased. Films containing CldO at 10 wt% and 15 wt % demonstrated enhanced antibacterial properties against certain pathogenic bacteria and biodegradation. In addition, all films showed resistance to 5 % NaCl, 3 % HCl, and 50 % ethanol solutions.