Potassium ethyl xanthogenate

TATATO, PETMP, 3-(triethoxysilyl)propyl isocyanate, 1,3-propanedithiol, 3-chloro-2-chloromethyl-1-propene, potassium ethyl xanthogenate, ethylene diamine, and propylamine were purchased from Sigma-Aldrich. Irgacure 819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide) and I651 (2,2-dimethoxy-1,2-diphenylethan-1-one) both were obtained from BASF. Schott glass (mean particle size 40 nm) untreated were generously donated by Evonik Silicas, and used as the inorganic fillers. Prior to implementation and as described later, these fillers were subsequently functionalized with thiol group for inclusion and copolymerization in the composite. All chemicals were used as received.

2,2-Bis[4-(2-hydroxy-3-methacrylyloxypropoxy) phenyl] propane (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (Esstech, Essington, PA, USA) were purchased from Esstech (Essington, PA, USA) as a premixed monomer mixture in 70:30 mass ratio. Pentaerytritol tetrakis(3-mercaptopropionate) (PETMP), Triethyleneglycol-Divinylether (TEGDVE), 1,4-diazabicyclo[2.2.2]octane (DABCO), 3-chloro-2-chloromethyl-1-propene, potassium ethyl xanthogenate, ethylene diamine, and propylamine were purchased from Sigma-Aldrich. Irgacure 819 (bis(2,4,6-trimethylbenzoyl)- phenylphosphineoxide) was obtained from BASF. Schott glass (mean particle size 40 nm) untreated were generously donated by Evonik Silicas, and used as the inorganic fillers. Prior to implementation and as described later, these fillers were subsequently functionalized with thiol group for inclusion and copolymerization in the composite. All chemicals were used as received. The thioester-diacrylate²⁰ and 2-methylene-propane-1,3-di (thioethyl vinyl ether) (MDTVE-AFT)^{21 (link)} were synthesized using methods reported elsewhere.

Potassium ethyl xanthogenate (96%), vinyl acetate (VAc, ≥99%), 2,2′-azobisisobutyronitrile (AIBN, 98%) and α-bromoisobutyryl bromide (98%) were purchased from Sigma-Aldrich (MO, USA). VAc was purified by passing through silica column and AIBN was recrystallized in ethanol before use. Triethylamine (99%, Acros, Belgium) and titanium dioxide (TiO₂, Aeroxide^®, P25, Acros, Belgium) were used as received.