Bisphenol a glycerolate dimethacrylate bis gma

The epoxy resin was bisphenol A type resin (YD-128, Kukdo Chemical, Seoul, Korea). Bisphenol A glycerolate dimethacrylate (BisGMA) as acrylate resin and fumed silica with a particle size of 0.25 µm and specific surface area of 395 m² g⁻¹ were purchased from Sigma-Aldrich (Sigma-Aldrich Korea, Seoul, Korea). Adipic acid dihydrazide (ADH) as conventional hardener was received from Tokyo Chemical Industry. Irgacure 651 (Ciba Specialty Chemicals, Basel, Switzerland) was used as a photoinitiator. To synthesize the PMMA/PEI core-shell nanoparticle, methyl methacrylate (MMA), branched PEI (M_n = 60,000), and tert-butyl hydroperoxide (TBHP; 70 wt% in H₂O) were obtained from Sigma-Aldrich (Sigma-Aldrich Korea, Seoul, Korea).

As stated above, four types of dihydrazide derivatives, including adipic acid dihydrazide (ADH, Tokyo Chemical Industry, Tokyo, Japan), isophthalic dihydrazide (IDH, Tokyo Chemical Industry, Tokyo, Japan), sebacic dihydrazide (SDH, Tokyo Chemical Industry, Tokyo, Japan), and 4-isopropyl-2,5-dioxoimidazolidine-1,3-di(propionohydrazide) (VDH, Ajinomoto Fine-Techno, Kanagawa, Japan), were utilized in this study and demonstrated in Figure 1. The epoxy resin was a bisphenol A-type epoxy resin with an epoxy equivalent weight of 184-190 g/eq (YD-128, Kukdo Chemical, Seoul, Korea). The acrylate resin of bisphenol A glycerolate dimethacrylate (BisGMA) was received from Sigma-Aldrich (St. Louis, MO, USA). The photoinitiator, Irgacure 651, was purchased from Ciba Specialty Chemicals (Basel, Switzerland). Fumed silica with an average diameter of 250 nm was obtained from Sigma-Aldrich (St. Louis, MO, USA).