Bio-based polymers obtained from modified fatty acids and soybean oil with tailorable physical and mechanical performance

Abstract

The impending world oil shortage, global climate changes, and environmental pollution encourage the use of natural renewable resources to produce substitutes for petroleum-derived polymers. In this work, two series of bio-based thermoset polymers are prepared by free radical polymerization of commercially available acrylated epoxidized soybean oil (AESO) with different amounts of methacrylated oleic (MOA) or lauric (MLA) acids. The characterization of the resulting cured bio-based copolymers is performed by infrared spectroscopy, dynamic mechanical analysis, thermogravimetric analysis, and tensile tests. Experimental results show that heat resistance index, storage modulus, and crosslinking density increase as the content of AESO in the samples increases, whereas the corresponding glass transition temperatures (Tg) decrease slightly. Samples containing MLA present higher tensile modulus and strength than polymers made from MOA or 100% AESO. All materials are insoluble in water and common organic solvents, show high transparency and water contact angles among 67° and 86.3°, and at least some of the samples demonstrate stress relaxation capacity. Practical Applications: The properties of the bio-based polymers obtained in this work can be adapted to different potential applications by selecting both the amount and type of constituents. Their tailorable physical and mechanical performance, malleability at elevated temperatures, moderate wettable surfaces, easy preparation, high content of bio-carbon, and environmental benefits make these novel bio-based polymers great candidates not only for structural applications but also as protective or decorative coatings.