Preparation of novel benzoxazine monomers containing ferrocene moiety and properties of polybenzoxazines

Novel benzoxazine monomers containing ferrocene were prepared, one monomer was monofunctional benzoxazine ferrocenylmethyl-3,4-dihydro-2H-1,3-benzoxazine (pC-fcma), and the other was bifunctional benzoxazine, bis(ferrocenylmethyl-3,4-dihydro-2H-1,3-benzoxazinyl)isoprapane (BA-fcma). Followed by thermal cure of monomers, metallopolybenzoxazines with ferrocene moiety in the polymer networks were obtained. The chemical structures of the novel monomers were confirmed by IR, 1H NMR and elemental analysis. The cure behaviors of the monomers, pC-fcma and BA-fcma were studied by DSC. The thermograms of BA-fcma showed multiple peaks, which were resulted from the quickly forming network and the bulkiness factor of ferrocene moiety. In addition, the first peak temperature was much decreased by nearly 70°°C than that of typical B-a benzoxazine, which was mainly due to the electron-donating effect of N-ferrocen group stability of zwitterionic intermediates. TGA suggested that thermal stability of metallopolybenzoxazines was improved, in particular, the weight loss temperature of 5% for polyBA-fcma was increased by almost 100 °C than that of PB-a, and the char yield even reached 60% at 800 °C under N2. Cyclic voltammetry studies of pC-fcma and BA-fcma showed that the species underwent one reversible and one-electron redox coupling.