Facile, one-pot synthesis of aromatic diamine-based phosphinated benzoxazines and their flame-retardant thermosets

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2010-10, Vol.48 (20), p.4555-4566
• Main Authors: Lin, Ching Hsuan, Lin, Hung Tse, Sie, Jhao Wei, Hwang, Kuen Yuan, Tu, An Pang
• Format: Article
• Language: English
• Subjects: Applied sciences; Benzoxazines; Chemical properties; Copolymers; Curing; Diphenyl methane; Epoxy cresol novolacs; Ethers; Exact sciences and technology; flame retardance; Mechanical analysis; Polymer industry, paints, wood; Properties and testing; Reproduction; ring-opening polymerization; Technology of polymers; thermosets
• ISSN: 0887-624X; 1099-0518; 1099-0518
• DOI: 10.1002/pola.24247

Three aromatic diamine-based, phosphinated benzoxazines (7-9) were prepared from three typical aromatic diamines--4,4′-diamino diphenyl methane (1), 4,4′-diamino diphenyl sulfone (2), and 4,4′-diamino diphenyl ether (3) by a one-pot procedure. To clarify the reaction mechanism, a two-pot procedure was applied, in which the reaction intermediates (4-6) were isolated for characterization. The structures of intermediates and benzoxazines were confirmed by high resolution mass, IR, and 1D and 2D-NMR spectra. In addition to self-polymerization, (7-9) were copolymerized with cresol novolac epoxy (CNE). After curing, the homopolymers of P(7-9) are brittle while the copolymers of (7-9)/CNE are tough. Dynamic mechanical analysis shows the Tgs of (7-9)/CNE copolymers are 187, 190, and 171 °C, respectively. Thermal mechanical analysis shows the CTEs of (7-9)/CNE copolymers are 46, 38, and 46 ppm, respectively. All the (7-9)/CNE copolymers belong to an UL-94 V-0 grade, demonstrating good flame retardancy.