Shape memory epoxy vitrimers based on DGEBA crosslinked with dicarboxylic acids and their blends with citric acid

Abstract

The shape of epoxy–acid based vitrimers can be changed either temporarily or permanently by selecting the appropriate thermal treatment.

Development of completely bio‐based epoxy networks derived from epoxidized linseed and castor oil cured with citric acid

“…The multiple pendant hydroxyl groups on the CO and the carboxylic acid groups of CA form polyester network through polycondensation process. Even after complete curing through epoxy‐acid transesterification reactions, a significant sol fraction is left . The free volume within cured sample and unreacted part of resin and acids is responsible for the lower glass transition (−8°C).…”

“…Even after complete curing through epoxy-acid transesterification reactions, a significant sol fraction is left. 26 The free volume within cured sample and unreacted part of resin and acids is responsible for the lower glass transition (−8°C). In highly crosslinked samples like in case of epoxy, the motion of chain segments is well restricted, which increased the Thus, T g could be determined more precisely from the peak of tan δ curve in DMA that is detailed in later section.…”

“…Thus, it is of great importance to utilize eco‐friendly curing agent preferably derived from renewable‐based resources to substitute petro‐based resources for producing next‐generation bio‐based epoxy networks . In this context, different bio‐derived carboxylic acids have been used, by several researchers in the past, as curing agents to develop both petro‐based and bio‐based epoxy products, with and without use of catalyst …”

“…20,21 In this context, different bio-derived carboxylic acids have been used, by several researchers in the past, as curing agents to develop both petro-based and bio-based epoxy products, with and without use of catalyst. [22][23][24][25][26][27][28][29][30][31][32][33][34][35] Supanchaiyamat et al prepared ELO-based thermoset cured with bi-derived diacid crosslinker in presence of different catalysts and found higher tensile strength with dimethylaminopyridine (DMAP) catalyst and Young's modulus by using imidazole catalyst. 27 Altuna et al synthesized self-healable green-epoxy network film from epoxidized soybean oil crosslinked with aqueous citric acid (CA) solution without use of any catalyst.…”

Diglycidyl ether of bisphenol A/chitosan‐graft‐polyaniline composites with electromagnetic interference shielding properties: Synthesis, characterization, and curing kinetics

“…Diglycidyl ether of bisphenol A (DGEBA) is the widely used monomer to produce ERs . DGEBA can be easily cured with different curing agents like amines , imidazoles , anhydrides , and carboxylic acids according to the purpose of use. Incorporation of various materials into epoxy systems would enhance their physical properties .…”