多官能性アクリレートの構造と物性

The purpose of this study is to clarify the superiority of the polyfunctional acrylate to the polyfunctional methacrylate in order to improve the dental restorative composites. Polymerization characteristics and various physical and mechanical properties of eight polyfunctional acrylates are described in comparison with those of twelve polyfunctional methacrylates. Homopolymerization : Polyfunctional acrylates showed a high rate and a high extent of polymerization compared with corresponding methacrylates. Two acrylates (TMPTA, NPGDA) in photo polymerization showed an excellent polymerization ability. No significant difference in the amount of water sorption (Ws) of the acryloyloxy group from the methacryloyloxy group was observed. The Ws was mainly depended on the chemical structure of oligomer block between two functional groups, and three methacrylates (2G, 3G, 4G) containing the ethyleneglycol chain and two acrylates (DPHA, TAC) showed high Ws among homopolymers tested. The dimensional change based on the water sorption was proportional to the Ws. The cured two acrylates (DPHA, TMPTA) and two methacrylates (1G, TMPTMA) showed high compressive strength (Cs), Vickers hardness (Hv) and abrasive resistance. In addition, the cured UDMA showed the highest diametral tensile strength (Ts). Copolymerization : No significant distinction in the Ws among copolymers tested was observed, although the solubility (So) of those copolymers was smaller than that of homopolymers. The high Cs and Ts were observed in the copolymers containing NPGDA, TMPTA, and DPHA. Photo polymerization provided generally the copolymers with higher Cs and Ts. The abrasive resistance of copolymers increased markedly compared with that of individual homopolymers. The copolymers containing TMPTA, DPHA and NPGDA prepared by heat curing showed the highest abrasive resistance among the materials tested. Composite : The high photo polymerization ability was observed in five experimental composites (EC) consisting of acrylates, and the depth of cure of these EC were large than that of EC not containing the acrylates. The amount of residual monomer in the EC obtained by heat curing was smaller than that of the EC by photo polymerization. The Ws of EC was nearly half of that of corresponding copolymers. No significant difference was observed among the Cs of EC, while the Ts of EC containing acrylates was higher than those of EC consisting of MP_<2・6>, 3G/BisGMA and three commercial composites except 0_<cc>. The EC containing acrylates showed the higher abrasive resistance compared to the EC of UDMA, MP_<2・6> and 3G/BisGMA, although it was slightly smaller than that of the corresponding copolymers. In conclusion, the polymerization characteristics and physical and mechanical properties of dental restorative composites consisting of polyfunctional methacrylates could be improved by adding polyfunctional acrylates in the comonomer system. The high photoreactivity of acrylates would be promising for the dental use of photo polymerized composites.