Synthesis and polymerization of epoxy methacrylates, 2 acylated epoxy methacrylates and their copolymers

Full Paper: Partially (20 - 75%) acylated isopropylidene-bis[1,4-phenyleneo xy(2-hydroxytrimethylene)] dimethacrylate (BisGMA) was prepared by a single step reaction of 2,2-bis[4-(2,3-epoxypropoxy)phenyl]propane (DGEBA) with m ethacrylic acid (MAA) methacrylic anhydride (MAAn) and/or acetic anhydride catalyzed by 0.8 mol % N-methylimidazole at 90-100 degreesC. In any case MA A was substituted by an equimolar quantity of the anhydride. The reaction k inetics of DGEBA with MAA and MAAn follows a first order law up to a conver sion of epoxy groups corredponding to the initial molar ratio of MAAn. For different mole fractions x(MAA) the reaction rate was found to be directly proportional to x (0.5)(MAA). The viscosity degree. Acylated BisGMA was cop olymerized with triethylene glycol dimethacrylate (TEGMA) by use of a redox initiator system at room temperature and with vinyltoluene (VT) initiated by di-tert-butyl peroxide at 150-200 degrees respectively, both in the pres ence of 70-76 wt.% of quartz filler. Different dependencies of the content of sol ad the conversion of C=C double bonds were observed for thermally po lymerised composites from VT with acetylated and methacrylated BisGMA, resp ectively. Methaceylated BisGMA yielded composites with reduced water uptake . The higher network density of the polymer matrix with methyacrylated BisG MA resulted in a higher glass transition temperature T-g and a higher stora ge modulus of the composites. The initial temperature of weight loss of com posites with BisGMA up to 258 degreesC for composites with BisGMA methyacry lated to a degree of 40%. [GRAPHICS] Formation of partially acylated BisGMA from DGEBA with MAA and the anhydrid es MAAn and AAn.