Thermally Controlled Acceleration of Epoxy Resin Curing through Polymer-Bound Imidazole Derivatives with High Latency

Abstract

Imidazole-containing polymeric accelerators were synthesized through free-radical polymerization and applied in the curing of diglycidyl ether of bisphenol A resin with the hardener dicyandiamide. Reactivity and storage stability were followed via differential scanning calorimetry, and an increased pot life was observed after incorporation into polymers. Depending on the employed monomers and composition, the compatibility with epoxy resin was adjusted and the storage stability thereby improved, while a high reactivity is retained under curing conditions. Microscopy imaging showed the dissolution of the polymeric accelerators in epoxy resin above a critical temperature enabling a high reactivity. The best performing accelerator was then applied in an epoxy adhesive film formulation. The strength of the bonding of stainless-steel test bodies was examined in a lap shear test showing superior long-term stability while maintaining efficient acceleration of this type of polymeric accelerator for adhesive applications.

Novel application of Zn‐containing Zeolitic Imidazolate Frameworks in promoting the vulcanization and mechanical properties of natural rubber composites

“…The possible reason is attributed to the presence of imidazole moiety. It has high reactivity under appropriate heating conditions, for instance, acting as a thermal initiator in the curing of epoxy resin 38 . Likewise, we speculated that the hydrogen atom of N‐imidazole group could capture some radicals generated during NR aging so as to further disrupt the degradation/crosslink reactions partly.…”

“…It has high reactivity under appropriate heating conditions, for instance, acting as a thermal initiator in the curing of epoxy resin. 38 Likewise, we speculated that the hydrogen atom of N-imidazole group could capture some radicals generated during NR aging so as to further disrupt the degradation/crosslink reactions partly. In addition, the low thermal conductivity of porous ZIF-8 (the simulation result is 0.165 W/m K 39 ) was supposed to obstruct heat transfer and afford NR matrix with good thermal aging resistance.…”

Synthesis and Characterization of Fully Biobased Epoxy Elastomers Prepared from Different Plant Oils

“…After raising the temperature from room temperature to 250 °C, only an exothermic peak was observed at 234.3 °C when no catalyst was applied . After DMAP, imidazole and 1,2-dimethylimidazole were applied, the exothermic peak obviously shifted to low temperature (208.8, 162.8, and 137.3 °C). It indicated that 1,2-dimethylimidazole seems to be the ideal catalyst to prepare biobased epoxy elastomers from Priamine 1074 and ESO under relatively mild reaction conditions.…”

Improve the Crosslinking Reactivity of Nitrile: Design of Nitrile‐Functionalized Pyrazine and its Hydrogen Bond‐Assisted Nucleophilic Enhancement Study

“…[3,4] In materials science, crosslinking reactions are widely used in the preparation of gel materials, 3D DOI: 10.1002/marc.202300199 printing materials, and thermosetting resins, among others. [5][6][7][8][9][10][11][12][13][14][15] However, some crosslinking reactions, such as those based on nitrile chemistry, still face the challenge of harsh reaction conditions, which limit their application. [16,17] Enhancing the reactivity of nitrile is crucial for expanding the application of 3D crosslinking materials.…”