Methacryloyl Derivitized Hyperbranched Polyester. 1. Synthesis, Characterization, and Copolymerization

Three hyperbranched multi-methacrylates (H20-MMA, H30-MMA and H40-MMA) have been synthesized by reacting Boltorn dendritic polyols with methacrylic anhydride and methacryloyl chloride. Their structures were characterized by FT-IR and NMR (1H and 13C) and molecular weights were measured by GPC. These multi-methacrylates (H-MMAs) mixed well with a variety of monomers such as acrylic acid (AA), methacrylic acid (MA), methyl methacrylate (MMA), 2-hydroxy-ethyl methacrylate (HEMA), tri(ethylene glycol) dimethdimethacrylate (TEGDMA), and bisphenol A glycidyl dimethacrylate (BisGMA). The initial studies on thermal polymerization activities of 10% of H-MMAs with AA, MA, and MMA showed that they gave higher polymerization enthalpy than the corresponding homopolymerization. The resulting materials showed one glass transition temperature, indicating a typical single-phase resin. The H-MMAs can effectively copolymerize with AA, MA, and MMA, with essentially no homopolymers produced, as indicated by acetone extraction studies. This indicated that the hyperbranched multi-methacrylates have the potential to be used as crosslinking agents or modifiers with a number of monomers to produce new thermosets.