Influence of the presence of disulphide bonds in aromatic or aliphatic dicarboxylic acid hardeners used to produce reprocessable epoxidized thermosets
Abstract
The design of polymers from renewable resources with recycling potential comes from economic and environmental problems. This work focused on the impact of disulfide bonds in the dicarboxylic acids reactions with three epoxidized vegetable oils (EVOs). For the first time, the comparison between arom. vs. aliph. dicarboxylic acids, contg. or not S-S bonds with EVOs was discussed and evaluated by dynamic scanning calorimetry. The obtained thermosets showed reprocessability, by the dual dynamic exchange mechanism. The virgin and reprocessed materials were characterized and the thermomech. properties were compared. The thermosets derived from EVOs with high epoxy content combined with arom. diacids contg. disulfide bridges showed high glass transition values (~ 111°C), high crosslink densities and good solvent stability.