Copolymerisation of 2-hydroxyethyl methacrylate with siloxanyl monomers

Acryloxymethylpentamethyldisiloxane (AMS) and methacryloxymethylpentamethyldisiloxane (MMS) have been prepared and purified chromatographically. Some physicochemical properties have been measured for these monomers as well as for highly purified 2-hydroxyethyl methacrylate (HEMA). Hydroxyl group analysis on copolymers of AMS with HEMA and of MMS with HEMA, obtained by free radical copolymerisation to low conversion, enabled monomer reactivity ratios to be determined by several procedures. The average values were r_HEMA = 0.86, r_AMS = 0.55 and r_HEMA = 0.97, r_MMS = 0.33. These values have been invoked in computing integral curves for the instantaneous copolymer composition throughout the whole range of conversion.