Research On The Preparation, Characterization Of Polymerically-Modified Clays And Their Polymeric Composites

The preparation,characterization and properties of polymerically-modified clays and their nanocomposites were studied.A series of oligomers were synthesized by free-radical polymerization of a mixture of styrene,vinylbenzylchloride and different polar monomers,including acrylamide,acrylonitrile,acrylic acid,and methyl methacrylate.And their quarterly ammonium salts were obtained from the reaction of trimethyl amine with the corresponding oligomers.The polymerically-modified clays were prepared through cationic exchange of the sodium ions in the clay gallery with the corresponding quarterly ammonium salts.Another industrial favorite method was used to prepare these polymerically-modified clays.In this method,corresponding quarterly ammonium salts were obtained by chloromathylation of oligomers.These polymerically-modified clays were charactered by IR, TGA,XRD and TEM.XRD traces and TEM images have shown that these modified clays are of well-intercalated or exfoliated structures. TGA data indicated that these polymerically-modified clays have better thermal stability than long chain modified clays.Polycarbonate(PC)/clay composites have been prepared by melt blending of PC with PSMMA-clay and PSAN-clay,respectively.The experimental results have showed that the mechanical properties of PC/clay compsites are significantly improved.XRD and TEM analysis have shown that these composites are of intercalated structures.The thermal analysis results have indicated that the thermal stability of PC/clay composites has been enhanced at clay loading of 1%.The DSC behaviors of PC/PSMMA-clay and PC/PSAN-clay composites have shown that the Tgs of all the clay composites are lower than that of virgin PC.MFR study of composites has been shown that the MFR values increased with the increasing content of loaded clays.Bisphenol A epoxy diacrylate(EA)/clay nanocomposites and polyurethane acrylate(PUA)/clay nanocomposites were prepared by UV-curing from a series of polymerically-clays.The effects of surfactant chemical structure on the morphology and physical properties were explored for nanocomposites formed from EA,PUA and polymerically-modified clays.The solvent-swelling properties have indicated that PSAM-clay and PSAA-clay can be well-swelled in the prepolymers leading to a well dispersion of clay in composites.XRD and TEM have showed that the surfactants having hydroxyl or amino group shows better dispersion with some of the clay platelets fully exfoliated in the polymer matrix and these composites performance better mechnical properties.The reaction of reactive polymerically-modified clays grafting PC was studied.IR results indicated that PC has reacted with PSAM-clay and PSAA-clay.Based on this,PA6/clay-g-PC composites were prepared.The results suggested that the mechnical properties of composites have been significantly improved.