Preparation and properties investigation of epoxidized linseed oil based biopolymer films

Epoxy resin thin films are increasingly used in applications such as coating materials and insulating films. Bioresins produced from vegetable oils are a sustainable alternative to petroleum-based thermoset resins. Therefore, developing new films or coatings with bio-based content is essential. In this study, epoxidized linseed oil (ELO) was synthesized from linseed oil (LO) and blended with epoxy resin (ER) at a 3:2 wt ratio to obtain a bio-based matris. The ELO was characterized by FTIR and determination of iodine and epoxide groups. The films formed by adding calendula oil (CldO) at various concentrations (1-3-5-7-10-15 wt%) were characterized for their antibacterial, mechanical, thermal, swelling, water content, water vapor permeability, chemical resistance, and biodegradation properties. A remarkable enhancement in the film's tensile strength was noted, including up to 10 wt% CldO. The thickness of the film samples was reduced due to ELO and CldO. The pH values of all film samples ranged from 7.1 to 7.2, which is compatible with the skin's pH. The film's water vapor permeability ratio (WVTR) was relatively low, ranging from 0.0082 to 0.0661 g/(m2*d). Films with CldO showed antibacterial activity against some pathogenic bacteria. The biodegradation also increased with the increase in the CldO ratio, which was 15.34% for the 15 wt% CldO film over the 42 days