Emulsion-templated flexible epoxy foams

• Published in: Polymer (Guilford) Vol. 215; p. 123380
• Main Authors: Steindl, Patrick, Decker, Helena, Retzl, Bernhard, Jiang, Qixiang, Menner, Angelika, Bismarck, Alexander
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 12-02-2021; Elsevier BV
• Subjects: Ambient temperature; Carbon nanotubes; Compressibility; Curing; Curing agents; Cyclic loads; Emulsion templating; Emulsions; Energy dissipation; Energy loss; Energy loss coefficient; Epoxy resins; Flexible epoxy foam; Foams; Hysteresis; Nanotechnology; Nanotubes; Plastic foam; Pore size; Porosity; Thickening agents; Flexible epoxy foam; Emulsion templating; Energy loss coefficient; Hysteresis
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2021.123380

Flexible epoxy foams were successfully prepared by curing medium internal phase emulsions (MIPEs) with a continuous organic phase containing epoxy resin and hardener, surfactant and carbon nanotubes and an aqueous internal phase. Curing the MIPEs at ambient temperature resulted in interconnected polyepoxide foams with average pore size of about 10 μm, while curing the MIPEs (with carbon nanotubes as a thickening agent) at 50 °C resulted in epoxy foams with pore sizes of one magnitude higher. The polyepoxide foams were compressible up to a strain of 70% of their original height and did not fracture. The polyepoxide foams were resilient with energy loss coefficients ranging from 40% to 60%, representing their energy adsorption during cyclic loading.
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•Flexible epoxy foams produced by curing emulsion containing epoxy formulations and CNTs.•Epoxy foams were compressible to a strain of 70% and had moduli of up to 0.3 MPa.•Epoxy foams had a hysteresis of 50% upon cyclic loading, indicating a low resilience.