title: Low viscosity dimethacrylate comonomer compositions [Bis-GMA and CH3Bis-GMA] for novel dental composites; analysis of the network by stray-field MRI, solid-state NMR and DSC & FTIR.
abstract: The effect of dilution of 2,2-bis (4-(2-hydroxy-3-methacryloxyprop-1-oxy) phenyl) propane (Bis-GMA) with 2,2-bis(4-(2-methacryloxyprop-1-oxy)phenyl) propane (CH3Bis-GMA) on extent of polymerization (Ep) was investigated by FTIR and NMR. The results correlate well with Ep values of the system and its flexibility probed by Tg (obtained by DSC). Spatially resolved photopolymerization kinetics and polymerization shrinkage (PS, i.e. volumetric polymerization contraction) was also studied by stray-field imaging (STRAFI-MRI). PS was obtained in the presence of oxygen from the atmosphere as the total volumetric contraction. All the results were compared with those obtained for the Bis-GMA/TEGDMA (triethylene glycol dimethacrylate) system. Use of Bis-GMA mixed with hydrophobic low viscosity CH3Bis-GMA comonomer, as a substitute for the commonly used TEGDMA, resulted in improving significantly properties such as PS, water sorption and Ep, thereby reducing the unreacted double bond concentration.
authors.affiliation: IST/ICTPOL, Departamento de Engenharia de Materials, Lisboa, Portugal.
authors.forename: Sónia Gama
authors.initials: SG
authors.lastname: Pereira
authors.forename: Teresa G
authors.initials: TG
authors.lastname: Nunes
authors.forename: S
authors.initials: S
authors.lastname: Kalachandra
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D003188:Composite Resins / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry*; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D008956:Models, Chemical; D010100:Oxygen / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D000179:Acrylates; D003188:Composite Resins; D003738:Dental Cements; D017438:Bisphenol A-Glycidyl Methacrylate; D010100:Oxygen