Benzoxazines derived from aniline and 4-hydroxybenzoic acid and from phenol and 4-aminobenzoic acid were prepared with two different synthetic approaches. When the carboxylic group reacted with epichlorohydrin, glycidylic derivatives M-1 and M-2, respectively, were obtained. The ring opening of benzoxazine and epoxy took place simultaneously with no catalyst for both monomers. Likewise, both ring-opening polymerizations took place when boron trifluoride monoethylamine (BF 3 ÁMEA) or 4-(N,N-dimethylamino)pyridine was used as a catalyst for M-1. However, for M-2, when BF 3 ÁMEA was used as a catalyst, the epoxy and benzoxazine ring openings could be distinguished, and a polyether intermediate containing benzoxazine side chains could be obtained.

Modified novolac resins with benzoxazine rings were prepared. The synthetic method involved the preparation of 1,3,5-triphenylhexahydro-1,3,5-triazine as an intermediate that further reacts with the novolac resin. The catalytic effects of phenols, carboxylic acids, and Lewis acids on the benzoxazine ring-opening polymerization were shown. The curing behavior of the benzoxazine compounds and the thermal properties of the cured resin were studied, and the results indicated improved degradation behavior for flammability. V-0 materials were obtained when the materials were tested for ignition resistance using the UL-94 test.

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Modified novolac resins with benzoxazine rings were prepared and copolymerized with a glycidyl phosphinate. Their curing behavior and the thermal properties of the curing resins were studied. Copolymerization was studied with model compounds considering the functionality of the benzoxazine‐based phenolic resins and the easy isomerization of the glycidyl phosphinate. Phenolic novolac resin acts as an initiator but p‐toluensulfonic acid had to be used to decrease the curing temperature and to prevent glycidyl phosphinate from isomerizing. The materials obtained exhibited high glass‐transition temperatures and retardation on thermal degradation rates. V‐0 materials were obtained when the materials were tested for ignition resistance with the UL‐94 test. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 279–289, 2004

Phosphorus‐containing novolac–epoxy systems were prepared from novolac resins and isobutyl bis(glycidylpropylether) phosphine oxide (IHPOGly) as crosslinking agent. Their curing behavior was studied and the thermal, thermomechanical, and flame‐retardant properties of the cured materials were measured. The Tg and decomposition temperatures of the resulting thermosets are moderate and decrease when the phosphorous content increases. Whereas the phosphorous species decrease the thermal stability, at higher temperatures the degradation rates are lower than the degradation rate of the phosphorous‐free resin. V‐O materials were obtained when the resins were tested for ignition resistance with the UL‐94 test. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3516–3526, 2004