EFFECTS OF THE STRUCTURE OF PARA-OLIGODIMETHYLSILOXANYL SUBSTITUENTS OF POLYSTYRENE ON GLASS-TRANSITION TEMPERATURE AND OXYGEN PERMEABILITY OF THE POLYMER

Polystyrenes with isomeric p-oligodimethylsiloxanyl substituents were synthesized in order to elucidate the roles of these substituents on their film forming properties and oxygen permeation behavior. Branched chain oligodimethylsiloxanyl substituents gave polymers with higher glass transition temperatures than did straight chain substituents. It was indicated from the permeation experiments that trimethylsiloxyl groups in p-oligodimethylsiloxanyl substituents played essential roles in permeation by increasing the diffusion coefficient. The roles of the substituents are further discussed based on the spin-relaxation behavior of the polymers in the solid state.