Abstract
The present paper deals with the optimum bleaching conditions and properties of ozone bleached douglas fir kraft pulp which were carried out with the addition of methanol as cellulose protector.
The optimum amount of methanol as the additive was 80100% on pulp. The addition of methanol containing H2SO4 did not have the combined effects of acidic medium and methanol addition from the point of inhibiting cellulose degradation.
By methanol addition in ozone bleaching, copper number of bleached pulp decreased, α-cellulose content increased, pentosan content slightly increased compared to control bleached pulps. Residual lignin of bleached pulp was lower than that of control bleached pulps.
The yield of bleached pulp increased a little and consumed ozone came to increase a little degree. Strength properties, such as breaking length and tear factor, improved compared to control bleached pulps.
