Preparation of Composite Materials of Waste Clay and Polymethyl Methacrylate Using Mechanochemial Polymerization in an Organic Solvent

Abstract

In order to use a waste clay effectively and to investigate mechanochemical polymerization as preparation method of the inorganic-organic composite materials, the mechanochemical polymerization of methyl methacrylate (MMA) was carried out by grinding the waste clay in n-heptane solvent. The waste clay was a halloysite with 16.2m2/g in specific surface area. The grinding operation was performed using a vibrating ball mill with a laboratory scale. The effect of monomer concentration in n-heptane solvent on the polymerization rate and the molecular mass of polymer were examined. As a result, the mechanochemical polymerization of MMA also proceeded by the grinding of the clay in n-heptane solvent. It was found that the polymerization rate increased with the increase of MMA concentration and that the conversion of MMA reached than 90%. Although the number average molecular mass of resulting polymer was in the order of 104 to 105, the molecular mass was decreased with the grinding time due to the scissions of polymer chains by the mechanical action. This polymerization mechanism was found to be radical reaction from the investigation of polymer tacticity. As for the composite of clay and PMMA obtained by the mechanochemical polymerization, a die molding was possible directly without kneading process.