The Changes in Physicochemical Properties of Lacquer Wax by Physical Adsorption and UV Light

摘要

In order to make the dark green pigments fade away and broaden the appliance of lacquer wax, both physical adsorption and ultraviolet (UV) irradiation were optimized and further compared in this paper. The optimal conditions of physical discoloration could be achieved in 80 °C when 20 mL petroleum ether blends with 1 g raw wax assisted by 5 % activated carbon/kieselguhr (1:1, m/m) as an adsorbent for 30 min, twice. A good bleaching effect of lacquer wax of UV radiation can be reached in 60 °C for 60 h. The CIEL~*a~*b~* system and Hunter whiteness formula were used to evaluate the discoloration effect. The value of peroxide, iodine, acid, and relative contents were imported to present the physical-chemical characterizations alteration. The chemical constituents variation of lacquer wax during the discoloration process was detected by GC-MS analyzer. A sharp increase of whiteness (by 54 %) occurred after these two processes and insignificant decrease in physical-chemical qualities indicated an effective and specificity method.