A novel method for preparation of exfoliated UV-curable polymer/clay nanocomposites

The half adduct of isophorone diisocyanate and 2-hydroxyethyl acrylate (IPDI-HEA), as a reactive organic modifier, was used to functionalize Na-montmorillonite (Na-MMT) clay. Unlike the electronic interaction in the conventional cation-exchange method, the driving force for the organic modification came from the chemical reaction between IPDI-HEA and framework hydroxyl groups on the surface of clay. With high degree of organic modification (48%), the d-spacing of clay layer was greatly enlarged to 3.32 nm, and the clay became more organophilic. After in situ photopolymerization among the IPDI-HEA grafted MMT clay, monomers and oligomers, the exfoliated polymer/clay nanocomposites were obtained. X-ray diffraction and transmission electron microscopy were used to detect the structure and morphology of the clay dispersed in the polymer matrix. Compared with the pure polymer materials, the exfoliated polymer/clay nanocomposites exhibited enhancements in mechanical and thermal properties.