From the synthesis and characterization of methacrylated fatty acid based precursors to shape memory polymers

Abstract

Fatty acid based precursors were synthesized by a one-step reaction from oleic or lauric acids and glycidyl methacrylate to be used later in polymer formulations. Different times of reaction, amounts of catalyst and initial ratios of reactants were evaluated, obtaining conversions higher than 0.9 for the best conditions. The monomers obtained are interesting alternatives to synthetics since they combine low cost with environmental advantages (i.e. higher bio-carbon content). These polymeric precursors were reacted separately in cationic and free radical polymerizations with styrene (50 wt%) to evaluate their potential as greener monomers. The lauric acid precursor and free radical polymerization were the alternatives that produced elastomeric materials with higher glass transition temperatures and storage moduli. These results were related to the lesser plasticizing effect of the shorter fatty acid chain, in comparison with that of the oleic acid based monomer, and to a lower free volume in the formed structure during curing. Moreover, all the obtained polymers exhibited shape memory properties that can be activated by temperature changes.