A new class of phenolic-like thermosetting resins based on the ring-opening polymerization of naphthoxazine precursor exhibits some unique properties

including：no by-product releasing during curing reactions；near-zero shrinkage and excellent mechanical properties．Polynaphthoxazines-clay hybrid nanocomposites were prepared from 1

5-dihydroxynaphthalene

aniline

formaldehyde and different proportion montmorillonite(MMT) by in-situ reaction in ethanol．1H-Nuclear Magnetic Resonance(1H-NMR)、X-ray Diffraction Analysis (XRD)、Thermogravimetry (TGA) and Transmission Electron Microscopy (TEM) were applied to characterize the nanocomposites．1H-NMR spectrum of naphthoxazine from the nanocomposites was identical to that of the pristine naphthoxazine

indicating the presence of MMT didn’t change the chemical structure of the product．The spaces of silicate layers of montmorillonite in the composites were investigated by using X-ray diffractometer．It was found that exfoliation structure was formed after in-situ synthesis reaction and was remained after being cured．The TEM results suggested that an exfoliated polynaphthoxazine-montmorillonite nanocomposite was successfully achieved. Dynamic TGA showed that only very small amount of clay is effective to improve the weight residues for nanocomposites．The char yield at 700℃ increased by ca．10％ with 5 wt％ MMT content in the nanocomposite and reached 65％．The confined crystallization behavior of the system was discussed．