Photoinduced grafting polymerization onto the surface with the use of radiation of high-power ultraviolet light-emitting diodes

The photoinduced grafting polymerization of acrylic acid onto the surface of a polypropylene film under the action of radiation with a wavelength of 365 nm and an intensity of 8–193 mW/cm 2 emitted by high-power UV light-emitting diodes is studied. Grafting is performed from a thin layer of the aqueous solution of the monomer onto the surface containing a photoinitiator (benzophenone) deposited from a solution in a volatile solvent. The amount of graft polymer is determined with the use of ATR FTIR spectroscopy. At an intensity of UV radiation of 193 mW/cm 2 , the time of attainment of grafting-polymerization saturation is decreased by a factor of 6 relative to this time at an intensity of 8 mW/cm 2 , typical for emitters based on mercury lamps. The rate of grafting polymerization in the studied UV-radiation-intensity range grows in proportion to the square root of intensity.