• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.23-32
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• 2015

In this study, chemical and physical changes of dissolving pulps which have similar viscosity by dry milling and fractionation were investigated. We used two types of dissolving pulp made from wood and cotton linter fiber, respectively. Dry milling was executed by knife cutter and pulp powders were fractionated by sieve shaker into 4 grades. We analyzed fiber properties, crystallinity index, viscosity, molecular weight of pulp sheet and powders. It was found that poly-dispersity index of cotton linter pulp was smaller than that of wood pulp, meaning that cotton pulp has more narrow molecular weight distribution. It was assumed that these were related to exposure times to chemical treatment which cut cellulose chains not evenly. At least 4 times of chemical treatments for wood pulp were executed and only two times of chemical treatments for cotton linter pulp were done. After dry milling average molecular weight and crystallinity index of cotton linter pulp powders were reduced and these were related to fines content and shape of pulp powders.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.566-577
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• 2015

White Jabon (Anthocephalus cadamba Miq.) is one of the fast growing species in Indonesia and has the potential as the raw material for pulp and paper. In this research, 3, 5, and 7 years old White Jabon woods were pulped under different active alkali charge of 15%, 18%, 21%, 24%, and 27%, and its effect on delignification degree, kappa number, pulp yield, pulp viscosity, brightness, unbeaten freeness, and delignification selectivity was investigated. The results showed that tree age and active alkali concentration influenced the quality of pulp and pulping properties, except for that of unbeaten freeness. Delignification degree increased with increasing active alkali charge, and this brought about the decrease of pulp kappa number. The pulping yield tended to decrease below the Klason lignin of approximately 4%. Even though the 3 years old wood resulted in the highest brightness and highest delignification selectivity, the highest pulp viscosity was obtained with the 5 years old wood. The dominant fiber length of all wood ages was in the range of 1.2 - 2.0 mm. The 3 years old wood was considered to be the most promising raw material for kraft pulping in the view point of pulping properties, pulp quality and harvesting rotation.

• Journal of Forest and Environmental Science
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• v.39 no.1
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• pp.27-39
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• 2023

Twenty-five Eucalyptus clones (14 E. camaldulensis - EC and 11 interspecific eucalypt hybrid clones - EH) grown in three contrasting sites were evaluated for the growth and few wood traits at 4 years of age. The stability, genotype-site interaction and suitability of these clones for pulp and solid wood industry sectors were studied. Growth of eucalypt clones was significantly higher at site 1 with higher rainfall, but wood density did not differ significantly from lower rainfall sites. Kraft pulp yield (KPY) decreased from sites 1 to 3 based on moisture availability, but not between two groups of clones. Volumetric shrinkage (VS) was significantly higher in EC clones at site 3 with lowest rainfall, but there was no specific trend at other two sites with maximum (site 1) and intermediate (site 2) rainfall. The mechanical traits modulus of rupture (MOR) and modulus of elasticity (MOE) were at par in sites 1 and 2, but significantly lower at the driest site 3. The growth rate had a significant positive correlation with KPY, MOR and MOE and a negative correlation with VS, but no significant impact on wood density in both groups of clones. Genotype×environment interaction (G×E) was evident in most traits due to the difference in response of clones to moisture availability. Since wood density was negatively correlated to KPY, it has to be kept at an optimum level for the profitability of pulp industry. There was no significant difference between EC and EH clones for most traits except VS at site 3. Stability of clones varied across sites in different traits, and hence clones may be selected for deployment at each site by screening for growth, followed by wood density, considering the relationship of growth and density with other traits required by pulp and solid wood industry sectors.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.81-87
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• 2015

Soda-AQ pulp made from sugarcane bagasse (SCB) were bleached in element chlorine free (ECF) sequence. To reduce chlorine dioxide use, final peroxide bleaching was introduced. Prior to peroxide bleaching, different chelating chemicals were applied for comparative analysis in ISO brightness and viscosity. When using equal total chlorine dioxide usage (4.5%), bleached SCB pulp using chelate and hydrogen peroxide (DEDQP) was reached 86.8% (DTPA), 86.4% (EDTA) ISO brightness, whereas bleached pulp using only hydrogen peroxide (DEDP) reached at 81.2% ISO brightness. Viscosity of DEDQP bleached pulp was 25.6 cPs (DTPA), 25.2 cPs (EDTA), And DEDP bleached pulp was shown 18.0 cPs viscosity. Decreasing of transition metal by chelate process led to improvements in final brightness along with higher viscosity. Due to EDTA is 5-7 times cheaper than DTPA, EDTA is recommended as chelating chemical prior to peroxide bleaching.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.5
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• pp.37-46
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• 2010

This study was carried out to develop new application field and obtain the basic data of mixed paper with wood pulp and chitosan fiber for producing functional paper. Two types of wood pulp, such as SwBKP and HwBKP, were mixed with chitosan fiber. Physical and optical properties, water vapor absorption, air permeability, antibacterial activity and ash were measured. And the surface morphology of manufactured paper was observed using SEM. The results are as follows. It was revealed that density, breaking length, burst index, tear index, folding endurance and brightness were reduced but water vapor absorption and air permeability were on the rise in the structural view of SwBKP according to increasing the chitosan fiber ratio. Those HwBKP added chitosan fiber were great not only in the strength but also water vapor absorption and air permeability except for brightness. The water vapor absorption was lower and the air permeability was higher in the HwBKP added various chitosan fiber ratios than those with no chitosan fiber. It is estimated that these properties were related with various mixed rate of chitosan fiber. Particularly, air permeability was strongly dependent on the mixed rate of chitosan fiber. The chitosan fiber has superior antibacterial property, comparing with wood fiber. Adding chitosan fiber to the wood pulp was found to have an excellent antibacterial activity, more than 90%. The ashes were determined within 0.5%. Special bonds between chitosan fiber and wood pulp was observed by SEM and it means that the chitosan fiber were combined equally in the interior of wood pulp. In conclusion, mixing wood pulp with chitosan fiber can not only improves the quality of paper but also extend the usage of paper as a functional paper by using inherent property of chitosan. After all, production of functional paper added chitosan fiber is expected for new valuable industry of paper.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.48-53
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• 2010

Commercial micro pulps(Arbocel) were coated with three kinds of polymers using spray method. These coated micro pulps were used to papermaking additives to evaluate retention, drainage and physical properties of paper. The retention and drainage were improved with addition of polymer coated micro pulp. The bulk index of paper was also increased, but tensile and tear strength were decreased slightly, probably due to weakening of internal bonding. These results showed that the use of polymer coated micro pulp was an effective method to improve retention, drainage and bulk index of paper.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.12-19
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• 2007

Enzymatic deinking method can avoids the alkaline environment as usual required in chemical deinking, which consequently cuts chemical costs and reduced the white water pollution. The electrostatic wastepaper was dinked with commercial cellulolytic enzymes and surfactant in neutral pH and the effectiveness of deinking and the physical properties of deinked pulp were evaluated. The disintegrating efficiency of the electrostatic wastepaper in neutral pH was enhanced with enzyme treatments. Although the freeness of deinked pulp with enzymes was higher than that of deinked pulp with chemical de inking agents, the brightness of the enzymatic deinked pulp was slightly lower than that of the chemical deinked pulp. But, by additions of nonionic surfactants, the brightness of deinked pulp was increased with less residual ink particles and mechanical properties of enzymatic deinked pulp was improved compared to the deinked pulp of conventional alkaline method.

• Journal of the Korean Wood Science and Technology
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• v.20 no.3
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• pp.67-78
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• 1992

The application of white-rot fungi to pulping and bleaching processes has been studied at the Wood Chemistry Laboratory in Kyushu University, cooperatively with the Biotechnology Laboratory of Kobe Steel, Ltd. Some successful results of the studies for a biomechanical pulping process, biobleaching of hardwood and softwood kraft pulp, as well as chlorine free biobleaching of oxygen-prebleached hardwood kraft pulp are dealt with. Biological treatment of the pulp bleaching effluent is also described.

• Journal of the Korean Wood Science and Technology
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• v.27 no.4
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• pp.65-71
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• 1999

This study was carried out to investigate the effect of xylanase pretreatment of the unbleached hardwood kraft pulp during the conventional Chlorine-Extraction- Hypochlorite (CEH) bleaching on pulp property. Optimum bleaching condition was evaluated by using Novozym produced from the fungus Humicola insolens. Also the effect of chelating agent prior to enzyme treatment was analyzed. The kappa number of enzymatic bleached pulp at the enzyme charge 10 IU/ml was slightly similar to that of bleached pulp without enzyme. By enzyme treatment, the chlorine charge in conventional CEH bleaching process of hardwood KP could be reduced by 17%, while no adverse effect on pulp yield and strength was. The optimum condition for enzyme pretreatment was 10 IU/ml xylanase charge, 3 to 4 hrs treatment, and 2% pulp consistency. In sugar composition in the enzyme pretreated pulp, arabinose and mannose were not much different, but more xylose was retained. This high content of hemicellulose in pulp seems to play an important role in pulp properties. The pulp pretreatment by chelating agent prior to enzyme treatment could improve the enzyme activity and enhance the bleaching effect at 0.2% diethylenetriamine pentaacetic acid (DTPA) charges.

• Journal of the Korean Wood Science and Technology
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• v.8 no.3
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• pp.64-76
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• 1980

Fig. 8 summarizes the present status of high yield pulp production and the directions of research on modification. A thick line indicates pulping process presently in use. As mentioned previously, one kind of modification is to introduce hydrophilic groups onto the pulp. Still unsolved is whether or not the introduction of hydrophilic groups should be restricted to lignin only. Goring (28) reported that middle lamella lignin has fewer phenolic hydroxyl groups than cell wall lignin and suggested that such a difference in the lignin may be useful in the removal of middle lamella lignin. The introduction of hydrophilic groups onto pulp may not be enough to modify high yield pulp. The removal of some portion of carbohydrate may be also necessary from the standpoint of softening of pulp fibers. There is no information at what lignin and carbohydrate, and how much should be removed. The combination with synthetic high polymers may also be important in modifying high yield pulp. Prof. C. Schuerch of the State University of New York who was a visiting professor at the University of Tokyo in 1974, mentioned that the hydrophilicity of lignin would be promoted, if phenolic hydroxyl or carboxyl groups could be introduced into the aromatic nucleus of lignin. If this were possible. this process would also mean a pulp yield of more than 100%. This idea is just one example of the expectation made possible through lignin chemistry. Instead of the introduction of hydrophilic group, the oxidative degradation of aromatic nucleus of lignin may also be useful in promoting the hydrophilicity of pulp. In this case, ozone may be an excellent chemical. However, there are a lot of problems to be solved such as homogeneity of reaction and selectivity of ozone for lignin. The above ideas are summarized in Fig. 9. There are many problems to be solved in the production of an excellent high yield pulp which is comparable to chemical pulp. The information from wood chemistry hopefully will elucidate some of the problems mentioned above.