The effect of a hindered amine light stabilizer on the aging behavior of moisture-curable polyurethane as a cultural relics consolidant

This paper aims to study the effect of a hindered amine light stabilizer (HALS 770), on the aging behavior of moisture-curable polyurethane (MCPU). MCPU is specifically developed by ourselves for the reinforcement of fragile organic cultural relics in high-humidity environments, but its aging resistance is insufficient. To improve the aging resistance of MCPU, HALS 770 was used to prepare a modified MCPU (MMCPU). A colorimeter, an infrared spectrometer and a thermal analyzer were used to characterize the color and structure changes of MCPU and MMCPU during aging and to determine their aging kinetics. The results show that the activation energy for the thermal decomposition increased from 91–109 kJ/mol to 135–151 kJ/mol. When the color change is used as the indicator for aging, the lifetime of MMCPU under UV aging is 133% longer than that of MCPU, the lifetime of MMCPU under thermal aging at 293 K is 41.3 times that of MCPU. The addition of HALS 770 to MCPU significantly inhibits the aging behavior.