The effect of designed wood storage on the brightness of bleached and unbleached thermo mechanical pulp

摘要

60 Norway Spruce (Picea abies) logs were stored in climate chambers for 14 weeks in order to investigate the effect of wood storage on the brightness of thermo mechanical pulp. The storage conditions were altered according to an experimental design comprised of five factors; light, watering, temperature, tree growth and debarking. Wood samples were collected during the storage period and refined into thermo mechanical pulp. ISO brightness values were measured for the unbleached, the dithionite bleached and the hydrogen peroxide bleached thermo mechanical pulp samples that were refined from the stored wood. The decrease in ISO brightness after 14 weeks of wood storage was significant for some of the samples bleached with dithionite. It was found that the interaction between watering and light had a significant negative effect on the brightness of the unbleached and dithionite bleached samples. The samples bleached with hydrogen peroxide generally showed a more consistent ISO brightness. Only watering and temperature had a significant effect on the brightness of peroxide bleached thermo mechanical pulp.