Effects of Pressure on Methyl Methacrylate Polymerization and Polymer Stereoregularity

Abstract

In a modest pressure range of 1–250 kg cm−2, the conversion and rate in free radical aqueous heterogeneous and homogeneous solution polymerization of methyl methacrylate increase with applied pressure to a maximum value and subsequently fall to attain a limiting value with further increase of pressure. Possible effects of pressure on kinetically important steps are discussed. The molecular weights also show similar variation with applied pressure due to enhanced chain-transfer with monomer at higher pressure. The thermal stability of the polymer is not influenced in this pressure range. 13C NMR spectra analyses of the polymer obtained at three different applied pressures do not reveal any differences in the percentages of isotactic, heterotactic and syndiotactic configurations in the polymer.