UV Curable Coatings: Effect of Diluents with 2, 2-Bis-[4-(2-hydroxy-3-acryloxy prop-1-oxy) phenyl] propane

Nine different formulations were prepared from the prepolymer, 2,2-bis-[4-(2-hydroxy-3-acryloxy prop-1-oxy)phenyl] propane with various functional diluents namely, monofunctional diluent, Di(ethylene glycol)ethylether acrylate, difunctional diluent, tri(ethylene glycol) dimethacrylate and trifunctional diluent, trimethylolpropane ethoxylate (1-ethoxylate/hydroxyl) triacrylate in the presence of photoinitiator, 2, 2dimethoxy-2-phenylacetophenone. These solutions were coated on the glass plates and then cured under ultraviolet radiation. The kinetics of photopolymerization, percent double bond conversion and rate of polymerization were studied by Fourier Transform Infrared Spectra. The results show that increasing irradiation time increases degree of conversion, whereas the rate of polymerization increases suddenly and then decreases. The gel content (%), hardness and density of the photocrosslinked polymers were studied. The swelling coefficient, crosslink density and molecular weight between crosslinks of the photocured polymers were determined by swelling measurement using N, N'–dimethyl formamide as a solvent. It is found that density, hardness and the gel content increases with increase of functionality in the diluents.