Preparation and characterization of thermoplastic polymers from hydroxyalkyl methacrylates

Soluble polymers have been produced from technical-grade 2-hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPHA) using a combination of vacuum distillation and solvent extractions to purify the monomers prior to solution polymerization. These extractions, particularly of HEMA with hexane and corn oil, were found to reduce the level of ethylene glycol dimethacrylate to < 1%, according to gas chromatographic analysis. Homopolymers of HEMA and HPMA and copolymers of HEMA with methyl methacrylate were prepared with a wide range of molecular weights and characterized by viscometry in dimethyl formamide, infrared spectroscopy including deuterium exchange experiments, and high resolution proton and carbon nuclear magnetic resonance (NMR) spectroscopy. The latter was used to determine copolymer composition and tacticity distribution.