Synthesis and properties of ultraviolet/moisture dual-curable polysiloxane acrylates



Ultraviolet (UV)/moisture dual-curable polysiloxane acrylates (PSAs) were prepared from N,N-bis[3-(triethoxysilyl)propyl]amine (G402) and ethoxylated trimethylolpropane triacrylate (EB160) through Michael addition. The obtained prepolymers were characterized by 1H-NMR and FTIR. The rheological behavior of the prepolymers exhibited the properties of a Bingham fluid and the apparent viscosity was directly correlated with molecular weight. The photocuring kinetics of PSA were studied using photo-DSC and all the polymerization conversions were high. With increasing content of tertiary amine in the prepolymer, the photocuring rate in air increased as well. The moisture-curing kinetics of the prepolymers was studied using FTIR. It was found that the curing mechanism may be described as the transforming of Si[BOND]O[BOND]C into Si[BOND]O[BOND]Si structure, which was consistent with the theoretical expectation. DSC and TGA were used to characterize the glass-transition temperatures and the thermomechanical stability of the prepolymers. Measurements of physical properties showed excellent gloss, impact strength, and high electric resistance for both UV- and moisture-cured films, but poor adhesion for UV-cured films and lower hardness for moisture-cured films. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 846–853, 2005