SYNTHESIS AND CHARACTERIZATION OF POLYFUNCTIONAL NAPHTHOXAZINES AND RELATED POLYMERS

In pursuing the new polymers that could provide high mechanical proper ties and good thermal stabilities, a series of naphthoxazines are synt hesized from different hydroxynaphthalenes with aniline and formaldehy de. The molecular structures are confirmed by NMR spectroscopy. After being polymerized in an autoclave, the naphthoxazine derived from 1,5- dihydroxynaphthalene is successfully cured to form the void-free resin . The density and tensile properties of these polynaphthoxazines are m easured. Dynamic mechanical tests are performed to determine the T-g, crosslink density, and the activation enthalpy of the glass transition process for the polynaphthoxazines postcured in air at different temp eratures. The effect of postcure temperature on the T(g)s of the polyn aphthzoxazines is investigated and discussed in terms of crosslink den sity. The polynaphthoxazine shows a T-g higher than the cure temperatu re. Fourier transform IR spectroscopy is applied for the molecular cha racterization of the curing systems. Thermal properties of these polyn aphthzoxazines are studied in terms of the weight loss after isotherma l aging in static air, the decomposition temperature from thermogravim etric analysis, and the change of dynamic storage moduli at high tempe ratures. (C) 1996 John Wiley & Sons, Inc.