Integrating ricinoleic acid derivates to thermoset polymers with tunable properties

Abstract

A highly functionalized biobased derivative of ricinoleic acid (MMRA) was synthesized through a two‐step procedure: maleinization of the hydroxyl group naturally present in this fatty acid followed by methacrylation of the carboxylic acid groups. The chemical structure of MMRA was confirmed by 1H NMR, infrared spectroscopy, gel permeation chromatography and analytical determinations. Thermoset polymers were further obtained by the free radical polymerization of MMRA with different amounts of styrene. The dependence of the color/transparency and tensile properties on sample composition was evaluated. Moreover, thermogravimetric and dynamic mechanical analyses were carried out to further characterize the obtained materials. All polymers were highly translucent with lightness values in the range 87.4?90.8 and opacity values below 13%. Their glass transition temperatures (Tg) ranged from 61.5 °C for the homopolymer MMRA to 104 °C for the copolymer containing 30 wt% MMRA. The rubbery storage modulus increased with MMRA content confirming the high functionality of the green precursor that led to polymers with high crosslinking density. Notably, pronounced damping capacity was also found in all copolymers made from MMRA / styrene.