Application of curcumin as a hydrogen abstraction photoinitiator in UV-curable pressure-sensitive adhesives
XIA Wei, ZHU Chong, CHEN Cunhua, LI Shengbiao
School of Chemistry， Central China Normal University/ Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction， Ministry of Education， Wuhan 430079， China
Abstract：In this study the application of natural bio-based compound curcumin was investigated as a hydrogen abstraction photoinitiator in UV-curable acrylate pressure-sensitive adhesives （PSAs）， aiming to address the environmental and health concerns associated with traditional petroleum-based photoinitiators and promote the green transformation of the adhesive industry. By comparing curcumin with commercial photoinitiators， the curing performance under different wavelengths （360 nm， 395 nm， and 420 nm） was evaluated. Experimental results showed that curcumin exhibited optimal initiation efficiency at a wavelength of 420 nm. At a concentration of w＝1.5%， curcumin achieved the same performance as TPO at w＝3%， with the PSA achieving a maximum 180° peel strength of 27.22 N·（25 mm）-1， loop tack of 13.60 N·（25 mm）-1， and holding time exceeding 99 hours. Furthermore， electron paramagnetic resonance （EPR） tests confirmed that curcumin can undergo a hydrogen abstraction reaction with hydroxyethyl acrylate （HEA）， generating α-hydroxyethyl radicals. As a hydrogen-abstraction-type photoinitiator， curcumin’s unique chemical structure enables certain hydroxyl-containing compounds （e.g.， HEA） to effectively replace traditional tertiary amine co-initiators， further simplifying the photoinitiation system. Characterization techniques such as Fourier-transform infrared spectroscopy （FTIR）， thermogravimetric analysis （TGA）， differential scanning calorimetry （DSC）， and scanning electron microscopy （SEM） further validated the excellent performance of curcumin. It’s demonstrated that curcumin， as a photoinitiator， offers promising potential for improving PSA adhesive performance and reducing environmental impact， highlighting its broad market application prospects.
2025, Vol. 59 
