Viscoelastic response of amine cured epoxy composites with imidazolium ionic liquid‐modified aramid pulp

• Published in: Journal of applied polymer science Vol. 141; no. 31
• Main Authors: Kerche, Eduardo Fischer, da Cruz, Joziel Aparecido, Ornaghi, Heitor Luiz, Schrekker, Henri Stephan, Amico, Sandro Campos
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 15-08-2024
• Subjects: Chloride; Chlorides; Composite materials; Dynamic mechanical analysis; Epoxy resins; Fiber pullout; Ionic liquids; Mechanical analysis; Mechanical tests
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.55740

Three ethanolic solutions containing different imidazolium ionic liquids (IL), namely 1‐butyl‐3‐methylimidazolium chloride, 1‐carboxymethyl‐3‐methylimidazolium chloride or 1,3‐dicarboxymethylimidazolium chloride), were used for the surface modification of aramid pulp (AP) (5 wt.% of IL in relation to AP mass) to improve its interfacial interaction with triethylene tetramine‐cured epoxy resin. Composites were prepared by casting with 0.4 phr of AP. Scanning electron microscopy, mechanical tests, isothermal dynamic mechanical analysis (at 1, 10 and 100 Hz), and conventional non‐isothermal analysis were performed. The IL‐modified AP (AP‐IL) presented greater defibrillation and strengthened interaction with the polymeric matrix, minimizing fiber pullout in the mechanical tests. The AP distribution in the epoxy matrix was assessed, and morphological changes were partly responsible for the improvement in the mechanical and dynamical mechanical response of the AP‐IL/epoxy composites. The AP/epoxy composite compatibilized with IL 1‐butyl‐3‐methylimidazolium chloride presented the lowest activation energy and, in turn, the strongest interaction with the epoxy matrix. Normalized DMA curves provided more detailed information on the differences between neat epoxy and the studied composites.