The Effect of Clay Modification on the Mechanical Properties of Poly( methyl methacrylate)/Organomodified Montmorillonite Nanocomposites Prepared by In Situ Suspension Polymerization

Poly(methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ suspension polymerization. MMT was previously organically modified by different modification agents [dioctadecyl dimethyl ammonium chloride (DODAC) and methacrylatoethyltrimethyl ammonium chloride (MTC)] and different modification method (cation-exchange reaction and grafting reaction), ultimately giving rise to five kinds of organomodified MMT (OMMT). The structure of the OMMT was studied by Wide angle X-ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FTIR). Meanwhile, the structure of the PMMA/MMT nanocomposites microspheres was also investigated by WAXD. The molecular weight of the polymers extracted from PMMA/MMT nanocomposites was measured by gel permeation chromatograph (GPC). Finally, the mechanical properties of these PMMA/MMT nanocomposites were studied in detail. It was found that large interlayer spacing (d001) of OMMT could not entirely ensure an exfoliated structure of resultant PMMA/MMT nanocomposites, while OMMT with relative small d001 could still yield exfoliated structure as long as the compatibility between OMMT and polymer matrix was favorable. In addition, the results of mechanical investigation indicated that the compatibility between OMMT and PMMA matrix turned out to be the dominant factor deciding the final mechanical properties of PMMA/MMT nanocomposites. (C) 2014 Society of Plastics Engineers