Curing and performance stability of urethane acrylates with different main chains under electron-beam irradiation

Four model urethane acrylates with different main chains (H-I-PEG1000, H-I-PPG1000, H-I-PEAG1000 and H-I-PCDL1000), and four control compounds without radiation-curable groups (B-I-PEG1000, B-I-PPG1000, B-I-PEAG1000 and B-I-PCDL1000) were synthesized using the same procedure. Attenuated total reflection Fourier transformed infrared spectroscopy (ATR-FTIR), nuclear magnetic resonance (NMR) spectrometry, and gel permeation chromatography (GPC) were performed to characterize the structures of these products. Then, the structure and performance of these products after electron-beam (EB) irradiation at various doses were investigated. The ATR-FTIR spectra revealed that the polymerization of acrylate CC was the main reaction that occurred during EB curing, whereas other groups exhibited no obvious change. GPC revealed that the ether-containing chains were more sensitive to EB irradiation, which could be attributed to the breakage and recombination of the molecular chain. The gel content, UV–vis transmittance, tensile properties, and basic properties of the cured films/coatings indicated that their performance stability is affected by the structure of the main chain.