Synthesis and Characterization of Novel Benzoxazine Monomers Containing Allyl Groups and Their High Performance Thermosets

Two novel benzoxazine monomers containing allyl groups:  3-allyl-3,4-dihydro-2H-1,3-benzoxazine and bis(3-allyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane have been synthesized from phenol and Bisphenol A with allylamine and formaldehyde. Their DSC exhibit two exotherms at ca. 145 °C and at ca. 220 °C which correspond to allyl and oxazine thermal polymerization, respectively. Both monomers undergo thermal cure with the formation of thermosets having excellent thermomechanical properties. These thermosets exhibit higher Tg (ca. 300 °C), maintain their storage moduli at higher temperature, and have better thermal stability than the corresponding polybenzoxazines without allyl groups.