Synthesis, characterization and UV curing kinetics of hyperbranched polysiloxysilanes from A₂ and CB₂ type monomers

A controllable approach to synthesize UV curable hyperbranched polysiloxysilanes from A₂ (1,1,3,3-tetramethyldisiloxane) and CB₂ type monomers (methyl(vinyl)silanediylbis(oxy)bis(ethane-2,1-diyl) diacrylate and methyl(vinyl) silanediylbis(oxy)bis(ethane-2,1-diyl)bis(2-methylacrylate)) was developed in the presented paper. The polymerization was monitored using FTIR, where a two-step polyaddition mode was observed. Vinyl silane group preferentially reacted with hydride silane, resulting in the formation of AB₂ type intermediates containing one hydride silane and two acrylate (or methacrylate) groups, at the same time, there may be low quantity of B₄ type intermediates. The intermediates further polymerized to form hyperbranched polymers. The UV curing kinetics of the hyperbranched polymers, especially the effects of atmosphere, content of photoinitiator and light intensity on UV curing behavior were studied in detail. The results indicated that the hyperbranched polymers could be cured rapidly under UV irradiation. The curing rates increased with the enhancement of light intensity, and the inhibition effect of oxygen could be restrained by increasing light intensity.