In response to the current problem of short absorption wavelength of photobase generator,which was difficult to match with commonly used visible light LED sources,based on the photosensitization mechanism,in this paper,a non-ionic photobase generator(PL-DBN)was synthesized by reducing amidine photobase generator,and its structure was characterized.It was compounded with photosensitizers(CQ,COU and ITX),three kinds of visible light sensitive photobase generator systems(PL-DBN/CQ,PL-DBN/COU and PL-DBN/ITX)were prepared,and their photophysical and photochemical behaviors were systematically investigated.The research results showed that,(1)The nuclear magnetic hydrogen spectrum indicated that the target product PL-DBN was successfully prepared.(2)By studying the light absorption properties of three kinds of photosensitizers,it was decided to select photosensitizers(CQ,COU and ITX)with different absorption ranges to be compounded with PL-DBN,respectively.(3)The efficiency of photolysis of different photosensitizers under 405 nm light source was investigated through steady-state photolysis experiments.Among them,PL-DBN/ITX showed a faster photolysis rate under 405 nm LED light source irradiation,making it more suitable for use in composite photobase generator systems.(4)Through the changes in UV-visible absorption spectra,it was found that the alkaline substances produced by the photolysis of the photobase generator system underwent acid-base neutralization reaction with phenol red,proving that PL-DBN could undergo photo induced alkali production reaction under 405 nm light source irradiation.(5)The effect of irradiation time on the kinetics of thiol-epoxy polymerization was investigated by using differential scanning calorimetry and Fourier transform infrared spectroscopy.The initial curing temperature of the system could be reduced by 23℃after 10 minutes of irradiation,and the conversion rate of thiol and epoxy functional groups could slowly increase to over 95%during a short period of heating after 10 minutes of light irradiation.(6)The bonding strength of the thiol-epoxy system after photothermal dual curing was tested.The thiol-epoxy system catalyzed by photobase generator had dark curing characteristics and could be applied in delayed curing adhesive,which had certain potential for future applications.
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