Evaluation of Effect of Steam Pretreatment on Water and Liquor Absorption of Wood Particles

This research was investigation of steaming pretreatment on water and liquor absorbtion by wood particles. In this study, wood particles steamed at two different temperature (110oC- 140oC), and then were saturated in water and liquor at two different temperature (25oC, 100oC). Liquor was supplied with two different consistencies. That is, sodium hydroxide %9, sodium sulfite %6 and sodum hydroxide %18, sodium sulfite %12. Result of this research has shown that maximum absorbed water was %95.5. It was treated with steam of 140oC for one hour, and minimum absorbed water was %68.9. It was treated with steam of 110oC for half an hour. So, maximum of absorbed liquor was %108.64. It was treated with steam of 140oC for one hour. And least of absorbed liquor was %99.88. It was treated with steam of 110oC for half hour. Moreover, maximum of water and liquor absorption for control samples were %94.98 and %107 respectively. However, they were less than treated samples

Effects of oxidized recycled fibers on paper properties

This research was conducted to find a procedure to increase the optical and strength properties of papers made from oxidized waste newspaper fibers. Samples of waste newspapers were randomly selected and deinked, then one part of deinked pulp was refined.  Both refined and unrefined recycled pulp were divided into two groups. In each case, a group of pulps was used to make standard hand sheets (control samples) without hydrogen peroxide treatment and only adding  2% cationic starch. Second group was subjected to  different percentages of hydrogen peroxide (2%, 3% & 4%) in alkaline conditions, then 2% cationic starch was added  to oxidized fibers prior to hand sheeting preparation and then standard hand sheets were made. Opticaland strength properties of all hand sheets were determined according to TAPPI standards. Also FTIR spectra was taken to specify the effect of oxidation on surfaces of pulp fibers. Results showed that treatment with oxidizing agent  increased the strength indices of papers. This increase was more evident when 3% hydrogen peroxide was applied. The  strengths of the control samples were the lowest. Moreover, refining imposed the positive effect on strength properties. Results of optical properties measurements indicated that as the extent of treatment for both refined and unrefined pulps increases, the brightness increased, and both the yellowness and opacity decreased. The highest brightness was reached when 3% peroxide was used. Also refining results in increased in brightness and yellowness  but decreas opacity.  FTIR spectra showed that samples of oxidized pulp had the greatest absorption at wave  number of 1650 which pertains to carboxyl group