3-Hydroxyflavone and N-Phenylglycine in High Performance Photoinitiating Systems for 3D Printing and Photocomposites Synthesis

Abstract

We propose to use 3-hydroxyflavone as a versatile high performance visible light photoinitiator (PI) in combination with an amino acid (N-phenylglycine) for the free radical polymerization (FRP) of methacrylates in thick samples (e.g., 3D printing) or composites upon visible light exposure (light-emitting diode LED@405 nm or LED@477 nm). The high originality of this approach is the use of safer compounds in photoinitiating systems (combination flavone derivative/amino acid). 3-Hydroxyflavone can also be used in three-component systems with an iodonium salt and an amine for the cationic polymerization of epoxides upon exposure to near-UV light LED@385 nm. Also interestingly, a charge transfer complex (CTC) between N-phenylglycine NPG and iodonium salt gives also remarkable initiating performance for free radical polymerization of methacrylates upon mild light irradiation conditions (LED@405 nm). High polymerization initiating abilities are found, and high final reactive function conversions are obtained. T...