The photopolymerization kinetics features of naphthyl(Meth)acrylates in melts

The photopolymerization kinetics of 1-, 2- and 1-bromo-2-naphthyl(meth)acrylates under an ultraviolet (UV) and visible light (VL) irradiation was investigated. It was found that a reactivity of the monomers in melts at temperatures 7 °C higher then Tmp near a melting point (photoinitiator dimetoxyphenylacetophenone) under UV irradiation decreases in row: 1-bromo-2-naphthylmethacrylate (1-Br-2-NМА) > 1-bromo-2-naphthylacrylate (1-Br-2-NА) > 2-naphthylmethacrylate (2-NМА) > 2-naphthylacrylate (2-NА) > 1-naphthylmethacrylate (1-NМА) > 1-naphthylacrylate (1-NА). It should be note that photopolymerization of naphthyl(meth)acrylates under UV irradiation occurs in the absence of a photoinitiator as well. Another trend takes places under VL irradiation: 2-NМА > 1-Br-2-NМА > 1-NМА > 1-Br-2-NА > 2-NА > 1-NА (photoinitiator 9,10-phenantrenquinone). The naphthylmethacrylates are shown to be more active as compared to the naphthylacrylates under UV and VL irradiation. X-ray structural analyses of naphthyl(meth)acrylates were carried out. It is shown that using information about naphthyl(meth)acrylates crystals structure allows rationally interpret the regularities of the photopolymerization kinetics these compounds under VL irradiation.