Figure 46 Preparation of poly (hydroxyethyl acrylate) in water by using NPD2-CD/MDEA system upon LED at 405nm irradiation.
The supramolecular complex DNND4/SBE-β-CD which was composed of DNND4 and sulfobutylether-β-cyclodextrin can also initiate polymerization reaction of HEA or hydroxyethyl methacrylate (HEMA) to obtain hydrogel under irradiation at 405 nm LED source.
The development of macromolecular water-soluble PIs with low-migration is extremely significant for achieving biosafety of photopolymerization. In terms of the preparation of hydrogels, Zhao et al.[160] designed and synthesized a new lignin-based water-soluble macromolecular PI L-PEG-2959 based on the Irgacure 2959, in addition, the function of PEG chain in L-PEG-2959 is to improve the water solubility of lignin. Transparent hydrogel can be prepared by using glycidyl methacrylate modified gelatin as monomer and L-PEG-2959 as PI. The synthesis of L-PEG-2959 and the preparation method of the hydrogel are displayed in Figure 47. Compared to the hydrogel containing Irgacure 2959, the extraction amount of L-PEG-2959 from the hydrogels was tremendously reduced, which indicates L-PEG-2959 is a promising macromolecular PI in fabricating biosafety hydrogel.