Novel phenolic modified acrylates: Synthesis, characterization and application in 3D printing

Three phenolic modified acrylate derivatives were synthesized by the reaction of nonylphenol (NP), 2-aminoethanol (AE) and paraformaldehyde (PA) with neopentyl glycol diacrylate (NPGDA), trimethylolpropane triacrylate (TMPTA) and 1,6-hexanediol diacrylate (HDDA), respectively. The molecular structures of the products were characterized by 1H NMR and electrospray ionization high resolution mass spectrometry (ESI-HRMS). The photopolymerization kinetics of phenolic modified acrylate was investigated by interval infrared spectroscopy. The results show that the phenolic modified acrylate with 1 wt% of 2-isopropylthioxanthone (ITX) can be cured to form a transparent film under UV irradiation. The UV curing speed of phenolic modified acrylate with 1 wt% of ITX was better than that of NPGDA with 1 wt% of ITX and 3 wt% of ethyl 4-(dimethylamino) benzoate (EDB) as co-initiator. The modified acrylate has high UV curing activity and low shrinkage of cured product due to the existence of active amine, aromatic rigid ring and flexible alkyl long chain structure. Based on DFT theoretical calculation, the hydrogen abstraction site of phenolic-modified acrylate was discussed, and the plausible photopolymerization mechanism was proposed. The composition of phenolic-modified acrylate and RJ313 resin can be 3D printed into various models with smooth surface, good precision and 99.7% of gel content.