Abstract
Ultraviolet (UV)/thermal dual-curable polyurethane acrylate (PUA) mixtures were prepared using a PUA oligomer, tripropylene glycol diacrylate (TPGDA), benzoyl peroxide (BPO), 2,4,6-trimethylbenzoyldiphenyl phosphine oxide (TPO), and cobalt isooctanoate. For purposes of comparison, a UV-curable PUA mixture was prepared by mixing the PUA oligomer, TPGDA, and TPO. When placed under a UV lamp (400 W, 50 mW/cm2), the surface drying time of each curable mixture was approximately 2 s. The content of volatiles during UV curing (the intensity of the lamp was 100 mW/cm2) was less than 0.3 wt%, and the content of potential volatiles (the test condition was heating at 110 °C for 1 h after UV curing) was below 1.0 wt%. Compared with the UV-cured sample, the UV/thermal dual-cured sample containing cobalt isooctanoate had more favorable properties, that is: (1) better acid and alkali resistance; and (2) better thermal stability and higher gel content. The temperature at 5 wt% weight loss (T5wt.%) and the gel fraction of the UV-cured sample (the curing condition was 1 min of UV irradiation) were 269.4 °C and 94.6%, respectively. The T5wt.% and the gel fraction of the UV/thermal dual-cured sample (cured at 100 °C for 10 min after 1 min of UV irradiation) were 318.2 °C and 99.8%, respectively. BPO and cobalt isooctanoate had little effect on the surface drying rate of the curable mixtures, and the performance of the cured samples was improved by thermal treatment following irradiation with UV. Considering the dyeing effect of BPO, this system provides a more practical approach to the complete curing of colored UV-curable resins.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
