Study of the addition of poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) thermoplastic to epoxy resin for use in self-healing composites

• Ano de defesa: 2017
• Autor(a) principal: Guerra, Érick Stéfano Silveira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM CIÊNCIA E ENGENHARIA DE MATERIAIS
• Palavras-chave em Português: Auto-reparo; Termoplástico-termofixo; DMA; FTIR; AFM; CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/23776

Repair of damaged composite structural elements to restore pristine conditions and meet regulatory requirements can be a great challenge. Thus, materials capable of self-healing when damaged are of great interest. In one of the self-healing approaches studied in the literature, thermoplastic is added to a thermosetting matrix and the damaged material partially recovers its mechanical properties after a healing cycle. This technique employs heat to trigger the healing process and partially reestablish the mechanical properties of the composite material. In the present study, poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (E-MA-GMA) thermoplastic was added to epoxy matrix and evaluated as a self-healing agent. The influence of the type of hardener employed (anhydride or amine) on the properties of the material was also investigated. Dynamic mechanical thermal analysis (DMTA) was performed to evaluate changes in viscoelastic properties due to the addition of thermoplastic. Fourier transform infrared (FTIR) spectroscopy was used to evaluate chemical alterations in thermoplastic-epoxy systems. Atomic force microscopy (AFM) was employed to examine the role of thermoplastic addition on epoxy network structure. Healing ability was assessed by comparison of areas damaged by indentations on the surface of samples before and after a healing cycle for materials with and without E-MA-GMA addition. Results suggest the presence of a E-MA-GMA second phase after curing, an increase in glass transition temperature (Tg) for all thermoplastic blended samples as compared to neat epoxy, the presence of one single Tg for epoxy anhydride hardened E-MA-GMA mixtures and chemical and structural alterations on the epoxy network due to addition of E-MA-GMA. Further, the elimination of visible damage areas of the material modified with thermoplastic after a heating cycle supports the potential use of E-MA-GMA as healing agent.