Epoxy resins with high heat resistance and flame retardancy via a new process

• Published in: Polymers for advanced technologies 2021-02, Vol.32 (2), p.474-483
• Main Authors: Kimura, Hajime, Ohtsuka, Keiko, Yonekawa, Morio
• Format: Article
• Language: English
• Subjects: Acidic oxides; Curing; Curing agents; epoxy resin; Epoxy resins; Fire resistance; Heat resistance; imide; Molecular chains; phenylethynylcarbonyl; polymer curing; Polymers; Thermal resistance; thermosets
• ISSN: 1042-7147; 1099-1581
• DOI: 10.1002/pat.5100

To develop highly heat‐resistant and flame‐retardant epoxy resins, the curing behavior of an epoxy resin and the properties of the resulting cured product were investigated using two compounds as curing agents, an acid anhydride containing a phenylethynylcarbonyl group and an imide compound with a phenylethynylcarbonyl group at both ends. The results indicated that reaction between the acid anhydride group and the epoxy group first proceeded at about 150°C to 170°C, followed by reaction between the phenylethynylcarbonyl groups at about 250°C to 300°C. The reaction between the acid anhydride and the epoxy group proceeded more efficiently in the presence of a small amount of the imide compound. The resulting product exhibited very good heat resistance and flame retardancy. The crosslink density was increased by polymerization of the phenylethynylcarbonyl group, and the resulting polyene structure and intramolecular imide skeleton strengthened intermolecular interactions, likely due to the limited freedom of movement of the molecular chains.