IMPROVING OPTICAL PROPERTIES OF SODA BAGASSE PULP USING COMPLEMENTARY BLEACHING WITH SODIUM HYDROSULFITE

摘要

Soda baggasse pulp was bleached by sodium hypochlorite and sodium hydrosulfite sequence and vice versa (reverse sequence). The optical behavior of the bleached pulps were determined by optical and thermal accelerated aging of the handsheetss. The characteristics such as brightness(R_∞), lightness (L~*), yellowness (b~*) and greenness (a~*) factors and also light absorption (k) and scattering (s) coefficients before and after aging were measured. Also, in this study, the effect of consistency (percent) and Fe~(2+) ion and a chelating agent (EDTA) on yellowing of paper were determined. The results indicate that appling a reductive bleaching stage-after oxidative treatment of the pulp will causes more brightness comparing to the reverse sequence.