Mechanochemical polymerization of methyl methacrylate initiated by the grinding of quartz in an n-heptane solvent

The information on mechanoradicals produced by grinding quartz in an n-heptane solvent was examined by means of electron spin resonance spectroscopy (ESR). The wet grinding of quartz was carried out by using a vibrating ball mill with a laboratory scale. The data of the ESR measurement revealed that E′ center radicals (Si) primarily produced from ground quartz in an n-heptane solvent and that the concentration of the mechanoradicals was approximately proportional to the specific surface area of ground quartz.The polymerization of methyl methacrylate (MMA) mechanochemically initiated by the grinding of quartz in the mixture solvent of n-heptane and MMA was also attempted by using the vibrating ball mill. The effect of the concentration of MMA monomer on the polymerization was investigated. As a result, the existence of the induction period to be observed well in radical polymerization was confirmed in all of the concentrations of MMA. It was found that the conversion of MMA increased with the decrease of MMA monomer and that the largest polymer yield was obtained at the concentration where the amount of monomer and solvent was the same in volume.

The data of the ESR measurement revealed that active E′ center radicals primarily produced from ground quartz in an n-heptane solvent. And the concentration of the mechanoradicals was approximately proportional to the specific surface area of ground quartz. By the existence of this radical, we were successful at mechanochemical polymerization of MMA in an n-heptane solvent.Figure optionsDownload as PowerPoint slideHighlights
► Mechanoradical was proportional to the specific surface area of ground quartz.
► The induction period was observed at all of the grinding with MMA.
► The conversion of MMA increased with the decrease of MMA monomer.
► Largest polymer yield was obtained at same volume of the monomer and the solvent.