三元乙丙橡胶紫外老化表观行为及纳米防老化剂作用机制

基于荧光紫外加速老化实验,追踪三元乙丙橡胶的老化过程,研究添加纳米防老化剂对材料表观老化行为和抗老化能力的影响,并利用傅里叶红外光谱和紫外吸收光谱分析纳米防老化剂的作用机制.随着老化时间的延长,试样表面粗糙度增加,色差和失光率变大,羰基指数上升,紫外吸收率下降.傅里叶红外光谱分析显示,表面二氧化硅膜包覆抑制了纳米二氧化钛的光催化作用,延缓了三元乙丙橡胶的老化进程.添加纳米防老化剂后,试样表面孔洞密度减少,色差和失光率分别降低0.97和22.29%,羰基指数下降0.06,紫外光吸收率升高3.92%,三元乙丙橡胶的抗紫外老化能力提高.

Surface behaviors of EPDM rubber and mechanism of nano anti-aging agent under UV condition

ABSTRACT Based on ultraviolet ( UV) accelerated aging tests, aging processes were tracked to study the effects of nano-TiO2 anti-aging agent on the surface aging behaviors and anti-aging ability of ethylene-propylene-diene monomer ( EPDM) . The anti-aging mech-anism was also analyzed by Fourier transform infrared spectroscopy ( FT-IR) and UV absorption spectroscopy. When the aging time prolongs, the surfaces of EPDM become rough, the chromatic aberration and the glossiness loss increase, the surface carbonyl index rises, while the rate of UV absorbance declines. FT-IR results demonstrate that with coating SiO2 , the photocatalytic degradation reac-tion of nano-TiO2 is inhibited and the aging process of EPDM is postponed. After adding nano-TiO2 anti-aging agent, the hole density decreases, the chromatic aberration and glossiness loss declines by 0.97 and 22.29%, respectively, the surface carbonyl index descends by 0.06, and the rate of UV absorbance increases by 3.92%. The anti-aging ability of EPDM enhances.