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Fluorinated main chain benzoxazine polyethers were prepared by Ullmann coupling of fluorinated benzoxazines in the presence of a nano-copperoxide catalyst. Various parameters such as the monomer structure, temperature, and the effect of catalyst on the polymerization were studied. The benzoxazine groups present in the polyether structure were shown to readily undergo thermally activated ringopening polymerization in the absence of an added catalyst forming cross-linked networks. The thermal stability of the cured polymers was investigated and compared to that of classical polybenzoxazines. The lower surface energy of the fluorinated polymers made ultrathin films ($20 nm thick) stable against dewetting at curing temperatures and resulted in thermally cured smooth coatings on solid substrates.

A new class of polybenzoxazine/montmorillonite (PBz/MMT) nanocomposites has been prepared by the in situ polymerization of the typical fluid benzoxazine monomer, 3-pentyl-5-ol-3,4-dihydro-1,3-benzoxazine, with intercalated benzoxazine MMT clay. A pyridine-substituted benzoxazine was first synthesized and quaternized by 11-bromo-1-undecanol and then used for ion exchange reaction with sodium ions in MMT to obtain intercalated benzoxazine clay. Finally, this organomodified clay was dispersed in the fluid benzoxazine monomers at different loading degrees to conduct the in situ thermal ring-opening polymerization. Polymerization through the interlayer galleries of the clay led to the PBz/MMT nanocomposite formation. The morphologies of the nanocomposites were investigated by both X-ray diffraction and transmission electron microscopic techniques, which suggested the partially exfoliated/intercalated structures in the PBz matrix. Results of thermogravimetric analysis confirmed that the thermal stability and char yield of PBz nanocomposites increased with the increase of clay content.

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