Synthesis and characterization of polybenzoxazine-clay nanocomposite

Abstract

A new polymer-silicate layer nanocomposite has been synthesized consisting of dispersed two-dimensional layers of organically modified montmorillonite (OMOM) within polybenzoxazine matrix proven by TG, XRD, TEM and FTIR. Five types of protonated amine derivative of OMOM were used to promote delamination of the host layers. The spacing of the host layers is strongly depended on size or molecular weight of amine derivative. Type of mono solvents and binary solvents have been studied and used to promote dispersion of OMOM in the mixture. The binary solvents that contain small amount of methanol show good ability to disperse OMOM. The important factors to prepare nanocomposite including ion-exchangeability of silicate layers, polarity of medium and the chemical nature of interlayer cation have been considered for the very well dispersion of silicate layers in the polymer matrix. XRD was used to determine the expansion of silicate layers in both OMOM and the nanocomposite films. It is found that the silicate layer expansion of all polymer-OMOM nanocomposites were quite similar ~ 4 Å. This is correlated with TEM results showing the aggregation of silicate layers. Thus the prepared nanocomposite are likely intercalated type. These results suggested that, among the three factors, the compatibility between modifying agent and monomer played the most important role.