Bioresource Technology 101 (2010) 1892–1898
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Bioresource Technology
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Effect of different locations on the morphological, chemical, pulping and papermaking properties of Trema orientalis (Nalita)
M. Sarwar Jahan a,b,*, Nasima Chowdhury a, Yonghao Ni b a Pulp and Paper Research Division, BCSIR Laboratories, Dr. Qudrat-E-Khuda Road, Dhaka 1205, Bangladesh b Pulp and Paper Research Centre, University of New Brunswick, Fredericton, Canada article info abstract
Article history: The chemical compositions and fiber morphology of stem and branch samples from Trema orientalis at Received 24 August 2009 three different sites planted in Bangladesh were determined and their pulping, bleaching and the result- Received in revised form 1 October 2009 ing pulp properties were investigated. A large difference between the stem and branch samples was Accepted 13 October 2009 observed. The stem samples have consistently higher a-cellulose and lower lignin content, and longer Available online 14 November 2009 fibers than the branch samples in all sites. T. orientalis from the Dhaka and Rajbari region had higher a-cellulose content and longer fiber length, resulting in higher pulp yield and better papermaking prop- Keyword: erties. The T. orientalis pulp from Rajbari region also showed the best bleachability. Trema orientalis, Variation of wood Ó 2009 Elsevier Ltd. All rights reserved. properties Stem and branch Pulping and bleaching
1. Introduction sely to those of Malaysian-grown mangium and other fast-grow- ing plantation species, including the traditionally-used pulpwood The increased demand for wood and fiber and declining avail- of the Philippines. ability of wood supplies have prompted investigations into the po- The T. orientalis is among the fastest growing trees in the tential of fast-growing species as raw material for the pulp and tropical and temperate regions and produce wood that can be paper industry. Among them, Eucalyptus, Acacia have received widely used by the paper industry. It is a native species grows much attention (Colodette et al., 2000; Cossalter and Smith, in many places in Bangladesh. At present it has no industrial 2003; Downes et al., 2003; Edgrard, 1999; FAO, 2005, 2009; Khrist- use. In earlier studies, we introduced this species as a pulping ova et al., 1997; Malinen et al., 2006; Patt et al., 2006; Santiago and raw material (Jahan and Mun, 2003, 2004; Jahan et al., 2008b). Neto, 2008a,b). Trema orientalis is also a fast-growing species and T. orientalis was characterized with high a-cellulose content. can be harvested in 3–4 years for valuable pulpwood (Jahan and Pulp yield and paper making properties were comparable to Mun, 2003). the Gmalina, which is presently used by the Kharnaphuli Paper Many studies have been carried out to evaluate some fast Mills in Bangladesh. growing wood species for the pulp and paper industry (Edgrard, Due to the differences in climate, soil and others, it is likely that 1999; Fidel and Tamayo, 2003; Jahan and Mun, 2003, 2004; Ja- the chemical, physical and morphological properties of the same han et al., 2007, 2008a; Khristova et al., 1997; Malinen et al., wood species but at different locations, are different, therefore 2006; Lei et al., 2006; Zhu et al., 2005). Triploid Populus tomen- affecting pulping and papermaking properties. For example, Goyal tosa a hybrid poplar has received much attention recently and it et al. studied the variability in pulping and fiber characteristics of can be made into chemical and mechanical pulp with quality hybrid poplar due to their genetic makeup, environmental factors (Chen and Mao, 2000; Zhu et al., 2005; Yang et al., 2006). Fidel and tree age (Goyal et al., 1999). and Tamayo (2003) determined the chemical composition of In this paper, we determined the potential of T. orientalis col- plantation grown Acacia mangium, and the results showed that lected in three different locations in Bangladesh, as potential raw the Philippine mangium’s chemical composition resembled clo- material for pulping and papermaking. The physical, chemical and morphological properties of the stem and branch samples were carried out. The kraft and soda-anthraquinone (AQ) pulping * Corresponding author. Address: Pulp and Paper Research Division, BCSIR trails of these raw materials were conducted. ECF bleaching T. ori- Laboratories, Dr. Qudrat-E-Khuda Road, Dhaka 1205, Bangladesh. Fax: +880 2 entalis pulps from different sites and stem and branch was also 86132002. E-mail address: [email protected] (M.S. Jahan). evaluated.
0960-8524/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2009.10.024 M.S. Jahan et al. / Bioresource Technology 101 (2010) 1892–1898 1893
2. Methods At the completion of cooking, the pulp was thoroughly washed, and screened in a flat vibratory screener (Yasuda, Japan). The 2.1. Material screened pulp yield, total pulp yield and screened reject were determined gravimetrically as the percentage of oven dried (o.d.) The T. orientalis samples (4 years old) were collected from the raw material. The kappa number of the resulting pulp was deter- Dhaka, Gaibandha and Rajbari districts in Bangladesh. Three trees mined in accordance with Tappi Test Methods (T236 om99). Three in each location were selected. The stem samples were prepared replicates were done and the average reading was taken. The accu- by removing 2 ft from top and bottom, while the branch samples racy of data was 95%. were prepared by removing 1 ft from the terminal. For the pulping experiments, the debarked log was chipped to 0.5 Â 0.5 Â 2cm 2.3. Evaluation of pulps size by hand. For the chemical analysis, the wood chips were ground in a Wiley mill and the 40–60 mesh size fraction was used. Pulps were beaten in a PFI mill to different revolution and hand- sheets of about 60 g/m2 were made in a Rapid Köthen Sheet Mak- 2.1.1. Analysis for chemical, morphological and physical properties ing Machine. The sheets were tested by following Tappi Standard The basic wood density was determined according to PAPTAC Test Methods: tensile (T494 om96), burst (T403 om97), tear Standard A. 8P. For the measurements of fiber length, the sample strength (T414 om98), folding endurance (T511 om96) and bright- ness (T525 om92). was macerated in a solution containing 1:1 HNO3 and KClO3. The macerated sample was taken in a slide and the fiber length was measured under a profile projector (Nikon V-12, Japan). The fiber 2.4. DEpD bleaching diameter was measured in an image analyzer.
The chemical compositions were carried out by following Tappi The brown stock samples were bleached in a DoEpD bleaching Test Methods: the extractive (T204 om88), 1% alkali solubility sequence. The kappa factor was 0.20 in the first Do stage. Other (T212 om98), water solubility (T207 cm99), Klason lignin (T211 conditions were: 70 °C, 5% pulp consistency, 60 min. The initial om83) and ash content (T211 os76). The holocellulose content pH was adjusted to 2.5 by adding dilute H2SO4. The conditions was determined by treating the extractive free wood meal with for the Ep stage were: 70 °C, 60 min, 10% pulp consistency, 2% NaClO2 solution Browining (1976). The pH of the solution was NaOH and 0.2% H2O2. The conditions for the D1 stage were: 3.5 maintained at 4 by adding a CH3COOH–CH3COONa buffer and the end pH, the ClO2 charge in the D1 stage was one half of that in a-cellulose content was determined by treating the holocellulose the Do stage. The brightness and viscosity (T230 om99) of the sample with 17.5% NaOH (T203 om93). bleached pulp were determined in accordance with Tappi Test Methods. 2.2. Pulping 3. Results and discussion The kraft pulping was carried out in a thermostatically con- trolled electrically heated digester. The capacity of the digester 3.1. Chemical, morphological and physical properties was 5 l. The normal charge was 300 g of oven dried (o.d.). The pul- ping conditions were as follows: A complete wood chemical analysis was performed to deter- mine the differences in chemical composition of T. orientalis in – Active alkali was 16–20% on oven-dry (o.d) raw material as relation to sites and stem and branch. Table 1 gives a summary
Na2O. of these results. The a-cellulose content of a raw material, which – Sulphidity was 25% (for kraft process). is directly correlated with pulp yield, varied significantly among – AQ was 0.1 on od raw materials (soda-AQ process). these sites. The a-cellulose content varied significantly among – Cooking time was 120 min at maximum temperature (170 °C). these sites. The highest content of a-cellulose (45%) was observed Ninety minutes were required to raise the maximum tempera- in stem from Dhaka and Rajbari, while the lowest content of a-cel- ture (170 °C) from a room temperature. lulose (41%) was observed in branch from Dhaka region. Similar – Liquor to wood ratio was 4. differences of T. orientalis branch and stem from Taiwan were
Table 1 Chemical, physical and morphological properties of stem and branch of T. orientalis from different sites.
Dhaka Gaybandha Rajbari Stem Branch Stem Branch Stem Branch Extractives, % Acetone 0.89 ± 0.02 1.52 ± 0.05 0.88 ± 0.03 0.97 ± 0.03 0.81 ± 0.04 1.7 ± 0.05 Cold water 2.4 ± 0.3 4.1 ± 0.3 2.3 ± 0.2 3.2 ± 0.3 3.2 ± 0.4 4.1 ± 0.4 Hot water 4.9 ± 0.3 5.3 ± 0.5 4.3 ± 0.4 5.5 ± 0.5 5.7 ± 0.5 6.0 ± 0.6 1% Alkali 21.4 ± 0.9 26.8 ± 1.1 24.6 ± 1.0 25.0 ± 1.2 22.8 ± 0.9 26.9 ± 1.2 Lignin, % Klason 24.1 ± 1.1 25.1 ± 1.2 24.0 ± 1.2 24.5 ± 1.1 23.6 ± 1.0 23.7 ± 1.1 Acid soluble 2.8 ± 0.2 3.7 ± 0.3 2.9 ± 0.3 3.2 ± 0.4 2.2 ± 0.3 3.2 ± 0.4 Pentosan, % 23.5 ± 1.0 22.7 ± 0.9 23.0 ± 1.0 23.6 ± 0.9 21.2 ± 0.8 23.5 ± 1.0 a-Cellulose, % 45.0 ± 1.6 41.4 ± 1.2 42.5 ± 1.3 42.0 ± 1.1 45.1 ± 1.2 43.1 ± 1.0 Ash, % 1.1 ± 0.05 0.73 ± 0.03 1.2 ± 0.02 0.9 ± 0.02 1.2 ± 0.03 0.7 ± 0.02 Density, g/cc 0.368 ± 0.03 0.330 ± 0.02 0.357 ± 0.02 0.351 ± 0.02 0.380 ± 0.03 0.364 ± 0.04 Fiber length, mm 1.34 ± 0.2 1.0 ± 0.06 0.89 ± 0.04 0.63 ± 0.04 0.83 ± 0.04 0.78 ± 0.03 Fiber diameter, lm 24.5 ± 1.0 23.5 ± 0.8 20.1 ± 0.8 19.4 ± 0.8 22.0 ± 0.9 20.5 ± 0.9 1894 M.S. Jahan et al. / Bioresource Technology 101 (2010) 1892–1898 noted (Ku et al., 1987). Generally the a-cellulose content in branch orientalis and other fast-growing species. The wood density of T. is lower than that in stem. orientalis was in general, lower than the other fast-growing species The average Klason lignin content in T. orientalis was 23–25%, (Miranda et al., 2001). which is consistent with other reported data for T. orientalis The fiber length is recognized as an important parameter for planted in other regions (Ku et al., 1987), higher than the Acacia pulp and paper properties, for example, it has a significant impact auriculiformis (Jahan et al., 2008a), A. mangium (Law and Daum, on the paper strength and paper machine runability (Jackson, 2000) and the Eucalyptus globules (Santos et al., 2008), but lower 1988; Watson and Dedswell, 1961). Table 1 also shows the fiber than the Eucalyptus camaldulensis (Fatehi et al., 2009). The lignin length of stem and branch samples of different sites. The stem content in branch was slightly higher than stem. There is no signif- samples showed consistently longer fibers than the branch sam- icant difference of Klason lignin content among these three re- ples, which is consistent with other wood species (Miranda et al., gions. The variation of total lignin content (acid soluble and 2001). The sample from Dhaka region exhibited longest fibers insoluble) content in T. orientalis from different sites was similar (1.34 and 1.00 mm, respectively, for the stem and branch samples) trend to that of the wood extractives. The lower wood density in comparison with Gaibandha and Rajbari regions. demonstrated increased amounts of lignin found in the wood. The pentosan content did not vary significantly among the sites 3.2. Pulping and stem and branch. It was about 21–23%, which was higher than that of A. mangium and A. auriculiformis (Malinen et al., 2006; Jahan Both kraft and soda-AQ pulping processes at various active alka- et al., 2008). The maximum amount of ash content was found in li charges were studied and the results are shown in Tables 2–4. Rajbari stem (1.2%) and the lowest amount found in Rajbari branch The pulp yield results from the stem samples were significantly (0.7%) and it was within the other tropical species (Khristova et al., higher than those from the branch samples, which are expected 1997). because of the higher a-cellulose content in stem samples. The to- The extractives contents, including those from acetone, cold tal pulp yields in Dhaka region T. orientalis were 51–49% and 49– water, hot water and 1% alkali, are all higher in the branch samples 47% in the kraft process for the stem and branch, respectively, than the stem samples. The 1% alkali solubilities in stem varied be- while they were 46–44% and 42–35% in the soda-AQ process. No tween 21% and 24%, while in branch it varied between 25% and reject was obtained in the soda-AQ process. In the kraft process, 27%. This difference may be due to the differences in weather the rejects were decreased and screened pulp yield increased with and soil conditions associated with the specific region. Extractives the increase of alkali charge in both stem and branch. In the kraft of a raw material are undesirable parts since they can have nega- process 20% alkali charge was required to reach the target kappa tive impact on pulping and bleaching operations. For example, a number of 20, while in the soda-AQ, the required alkali charge higher extractive content, in particular, 1% alkali solubility may was 16%. At the same kappa number of 20, the total pulp yield dif- lead to a lower pulp yield from the kraft and soda pulping pro- ference became minimize and reached to 2% for stem and 4% for cesses. The 1% alkali solubilities in Table 1 were lower than those branch (Figs. 1 and 2). of A. auriculiformis (Jahan et al., 2008). The samples from the Rajbari region showed the highest pulp As shown in Table 1, the wood density results of branch sam- yield in comparison with those of Dhaka and Gaybandha region, ples were slightly lower than those of the corresponding stem sam- which is consistent with the fact that the Rajbari region T. orientalis ples. Similar results were observed by Ku et al. (1987) for T. had the highest a-cellulose content among these three sites. Pulp
Table 2 Pulping of T. orientalis from Dhaka region stem and branch in kraft and soda-AQ processes.
Stem Branch Kraft Soda-AQ Kraft Soda-AQ
AA Na2O161820161820161820161820 SPY 46.5 49.9 47.4 46.0 45.8 43.8 44.3 47.0 47.0 42.0 39.5 35.0 KN 32.0 24.5 20.8 25.2 14.4 10.4 33.4 30.1 22.7 20.8 16.8 12.3 Rev 1720 1650 1510 1680 1380 1170 1730 1670 1450 1500 1350 1100 TI 13.8 13.7 12.9 11.0 9.3 7.9 10.8 9.9 8.4 9.1 8.8 7.6 TenI 45.6 49.9 50.1 42.4 43.8 42.3 45.0 47.0 48.1 42.4 42.5 40.0 BI 4.3 4.6 4.6 4.1 3.6 3.2 4.1 4.5 4.2 4.0 3.5 3.1 Fold 459 703 693 399 497 446 6344 580 5222 307 412 373
SPY, screened pulp yield; KN, kappa number; Rev, PFI revolution required to get 0SR 30; TI, tear index (mN m2/g); TenI, tensile index (N m/g); BI, burst index (kPa m2/g); fold, double fold number.
Table 3 Pulping of T. orientalis from Gaybandha region stem and branch in kraft and soda-AQ processes.
Stem Branch Kraft Soda-AQ Kraft Soda-AQ
AA Na2O161820161820161820161820 SPY 47.0 45.2 43.3 45.0 44.6 42.0 39.9 42.5 42.0 43.1 41.4 39.0 KN 20.8 19.9 19.0 18.4 15.8 14.0 31.0 23.5 15.9 22.3 17.0 13.5 Rev 1540 1500 1410 1320 1300 1250 1650 1460 1320 1460 1300 1170 TI 12.8 11.3 10.9 10.5 10.1 9.0 11.2 10.7 9.3 9.7 8.5 8.0 TenI 42.0 49.6 40.1 35.0 41.0 33.0 38.9 45.0 38.7 37.9 38.8 30.0 BI 3.9 4.3 4.2 3.3 4.0 2.9 4.3 4.0 3.6 3.1 3.3 3.2 Fold 1119 1191 1028 36 51 33 1242 1120 1030 50 54 63 M.S. Jahan et al. / Bioresource Technology 101 (2010) 1892–1898 1895
Table 4 Pulping of T. orientalis from Rajbari region stem and branch in kraft and soda-AQ processes.
Stem Branch Kraft Soda-AQ Kraft Soda-AQ
AA Na2O161820161820161820161820 SPY 49.5 49.0 48.0 49.7 50.4 50.3 48.6 48.0 47.0 48.6 49.3 49.5 KN 19.7 18.7 16.0 22.8 19.0 18.5 23.5 17.1 12.6 30.3 27.1 24.0 Rev 1510 1490 1340 1540 1480 1390 1550 1340 1130 1600 1520 1410 TI 9.5 11.4 9.0 9.2 10.6 10.2 8.7 10.7 8.0 8.7 10.0 8.8 TenI 49.6 48.2 43.2 44.7 48.2 43.8 46.0 45.8 43.9 42.8 40.0 39.5 BI 4.6 4.7 4.2 5.4 4.7 4.7 4.0 3.5 3.0 4.0 3.8 3.1 Fold 953 842 188 781 710 732 2867 584 552 1366 1484 1566
Fig. 1. The total pulp yield–kappa number relationship of different region T. orientalis in kraft process.
Fig. 2. The total pulp yield–kappa number relationship of different region T. orientalis in the soda-AQ process. yield of unbleached pulp at kappa number 20 was measured from et al., 2009). At kappa number 20, pulp yield from stem in soda- the pulp yield–kappa number plot in different alkali charge (Figs. 1 AQ and kraft process was almost similar in Gaybandha region, and 2) to evaluate the impact of sites of T. orientalis and shown in while soda-AQ process yielded 0.5% higher pulp yield than that Fig. 3. T. orientalis from Gaybandha had 4.5% lower pulp yield than of kraft process from the stem of Rajbari region. The branch sam- the Rajbari and 3.0% than the Dhaka and for stem. It has been dem- ples have consistently lower pulp yield and higher kappa number onstrated that kraft pulp yield is directly proportional to the alpha- than the stem samples for all the three sites. Such differences cellulose content of the wood (Hale, 1959). Pulp yield data were can be explained by the differences in the lignin content of these slightly lower than that reported of Eucalyptus globulus (Fatehi raw materials (Table 1), i.e., consistently higher lignin content in 1896 M.S. Jahan et al. / Bioresource Technology 101 (2010) 1892–1898
Fig. 3. Pulp yield of stem and branch of T. orientalis from different sites at kappa number 20. the branch than in the stem. The pulp yield from T. orientalis is low- 3.3. Papermaking properties er generally than the Eucalyptus (Colodette et al., 2000; Guerra et al., 2008) and higher than another fast-growing species Paulow- Depending on the end use of the pulp, the strength properties of nia (Ates et al., 2008). a pulp might also play a significant role in selection criteria. For Under different alkali charge, the kappa number of the pulps evaluating papermaking properties, pulps were beaten in a PFI mill from different sites was in the range of 13–33 (Tables 2–4). The for different revolutions and handsheets were prepared. The phys- kappa number of the stem is lower than that of the branch from ical properties at 0SR 30 were obtained from extrapolation. The the same site. These results suggest that the stem is easier to number of PFI revolution required to reach target 0SR 30 varied delignify than the branch. Among these three sites, the samples from 1320 to 1510 revolution depending on sample location and from Rajbari region is the easiest to delignify, which is due to whether it was from stem or branch (Table 5). The pulp made from the lowest lignin content (Table 1). It may be noted that the kla- branch required less refining than the stem pulp. son lignin content may not affect the delignification rate, other The strength properties tear, tensile and burst indexes at 0SR 30 factors, such as wood density may be more critical in determin- are also presented in Table 5. A significant difference exists among ing delignification rate, for example, Mortha et al. (1992) sug- the sites and also between the stem and branch samples of the gested that hybrid poplar for its higher delignification rate in same site. The tensile index of stem pulp from Dhaka region was kraft process is due to its lower wood density, so that the 4.1% higher than that of branch, while the stem samples from Gay- diffusion of lignin out of the wood chips can be explained. Our bandha and Rajbari was 10.0% and 5.2% higher than that of the present data support the same hypothesis. The lowest density branch samples, respectively, in the kraft process. of branch from Dhaka region T. orientalis produces pulp with The tear index also showed a variation among the sites. A stem the highest kappa number. Another explanation could be that pulp showed a higher tear index than a branch pulp. The higher tear the lignin structure of these sites is different. Nimz et al. and tensile indexes for the stem pulp are due to longer fiber lengths (1983) reported that b-O-4 linkages in guaiacyl units are (Table 1). Pulp from Dhaka region stem had the highest tear index hydrolyzed at a slower rate than syringyl units. A straight line (12.7 mN m2/g) in the kraft process, which is 0.9–3.4 mN m2/g correlation between delignification rate and the ratio of syringyl higher than that of Gaybandha and Rajbari stem pulp. The branch to guaiacyl propane units was also obtained by Chang and pulp from Dhaka region had the lowest tear index (8.4 mN m2/g) Sarkanen (1973). Since the syringyl content of a typical hard- and the Gaybandha region branch pulp had the highest tear index wood can vary from 20% to 60% (Fengel and Wegener, 1989), (10.7 mN m2/g) from the kraft process. The soda-AQ pulp showed the higher rate of delignification is most likely due to inferior tear index than the kraft pulp. The burst index is not af- higher syringyl contents in the native lignin of T. orientalis from fected by environmental factors (Table 5). Slight variation of burst Rajbari. index was observed between stem and branch.
Table 5 Physical properties (at 30 0SR by extrapolation) of stem and branch pulp from T. orientalis obtained from different regions at kappa number 20 by extrapolation.
Dhaka region Gaybandha region Rajbari Kraft SAQ Kraft SAQ Kraft SAQ Stem Branch Stem Branch Stem Branch Stem Branch Stem Branch Stem Branch Rev 1510 1470 1520 1490 1540 1420 1340 1360 1510 1500 1500 1320 TI 12.7 8.4 10.3 9.1 11.8 10.7 10.6 9.0 9.3 8.9 9.2 7.0 Ten 50.3 48.0 43.1 42.4 49.5 45.0 38.5 37.5 48.6 46.7 48.5 38.6 BI 4.5 4.1 3.8 3.8 4.3 3.8 3.2 3.2 4.6 3.9 4.8 2.4 M.S. Jahan et al. / Bioresource Technology 101 (2010) 1892–1898 1897
Table 6 Bleachability of T. orientalis pulp from different region in Bangladesh.
Brightness, % Viscosity, mPa s Kraft Soda-AQ Kraft Soda-AQ Dhaka Stem 84.1 85.6 15.8 15.2 Branch 84.9 85.8 12.6 13.5 Gaybandha Stem 82.5 81.9 16.3 16.4 Branch 85.6 83.1 12.8 13.2 Rajbari Stem 85.7 85.0 15.5 15.7 Branch 85.8 84.5 13.1 13.6
3.4. Bleaching viding financial support from Special Allocation Project to carry out this research. In recent years chlorine dioxide is completely taking place of elemental chlorine in the production of bleached chemical pulp to minimize the environmental impact. Chlorine dioxide is effec- References tive in delignifying as well as brightening chemical pulp. Unbleached pulps, with different kappa number, obtained from Ates, S., Ni, Y., Mehmet, A., Ayhan, T., 2008. Characterization and evaluation of Paulownia elongota as a raw material for paper production. African Journal of three different sites from stem and branches were submitted to a Biotechnology 7 (22), 4153–4158. conventional ECF sequence (DoEpD1). Brightness of pulp was in- Browining, B.L., 1976. Methods in Wood Chemistry. J. Wiley and Sons Interscience, creased with the increase of alkali charge during pulping (data New York. Chang, H.M., Sarkanen, K.V., 1973. Species variation in lignin: effect of species on not shown). This can be attributed by higher kappa number of the rate of kraft delignification. Tappi Journal 56 (3), 132–134. brownstock pulp. Bleachability tends to decrease as the kappa Chen, Z., Mao, Q., 2000. Characteristics of Triploid Populus tomentosa Carr. and its number increases (Jahan et al., 2008). In order to evaluate the application in pulping and papermaking. China Pulp Paper 21 (10), 17–20. Colodette, J.L., Gomide, J.L., Girard, R., Jaaskelainen, A.S., Argyropoulos, D.S., 2000. bleachability of these pulps, brightness was measured at kappa Influence of pulping conditions on hardwood pulp yield, quality and number 20 from extrapolation, where the same amount of chemi- bleachability. In: International Pulp Bleaching Conference, June 27–30. cals were used. The results of bleaching experiments are presented Halifax, NS, Canada, pp. 41–48. in Table 6. Pulp from Rajbari region showed better bleachability Cossalter, C., Smith, P.C., 2003. Fast-wood Forestry Myths and Realities. CIFOR, Jakarta, Indonesia. p. 50. than that of Gaybandha and Dhaka region. Branch pulp responded Downes, G., Evanes, R., Wimmer, R., French, J., Farrington, A., Lock, P., 2003. Wood, slightly better bleachability than that of stem pulp. Kraft pulp pulp and handsheet relationships in plantation grown Eucalyptus globulus. showed better bleachability than soda-AQ pulp. The kraft pulp Appita Journal 56 (3), 221–228. Edgrard, C., 1999. Sustainable plantations of high-yield Eucalyptus trees for from Gaybandha and Rajbari region had 0.6–1.5% higher brightness production of fiber: the Aracruz case. New Forests 17, 129–143. than the corresponding soda-AQ pulp. Lina and Leelo (2002) FAO, 2005. State of the World’s Forest. Rome, Italy, p. 135. showed that the higher bleaching chemical was required when FAO, 2009.
Law, K.N., Daum, R.W., 2000. CMP and CTMP of a fast-growing tropical wood: Acacia Patt, R., Kordsachia, O., Fehr, J., 2006. European hardwoods versus Eucalyptus maingium. Tappi Journal 83, 1–7. globulus as a raw material for pulping. Wood Science and Technology 40, 39–48. Lei, X., Chen, J., Lin, L., Yang, G., Kong, F., Pang, Z., 2006. Study on APMP pulping Santiago, A.S., Neto, C.P., 2008a. Eucalyptus globulus kraft process modifications: effect properties of several fast-growing wood materials. Zhongguo Zaozhi 25 (1), 69– on pulping and bleaching performance and papermaking properties of bleached 70. pulps. Journal of Chemical Technology and Biotechnology 83, 1298–1305. Lina, H., Leelo, O., 2002. Soda-AQ pulping of softwood, the influence of cooking Santiago, A.S., Neto, C.P., 2008b. Anthraquinone addition to Eucalyptus globulus kraft parameters on fiber properties and bleachability. Paperi ja Puu 84 (1), 43–49. pulping towards the reduction of operating sulfidity levels. Appita Journal 61 Malinen, R.O., Pisuttipiched, S., Kohelmainen, H., Kusuma, F.N., 2006. Potential of (4), 316–322. Acacia species as pulpwood. Appita Journal 59, 190–196. Santos, A., Amaral, M.E., Vaz, A., Anjos, O., Simoes, R., 2008. Effect of Eucalyptus Miranda, I., Almeida, M., Helena, P., 2001. Provenance and site variation of globulus wood density on papermaking potential. Tappi Journal (May), 25–32. wood density in Eucalyptus globulus labill. at harvest age and its relation to Watson, A.J., Dedswell, H.E., 1961. Influence of fibber morphology on paper non-destructive early assessment. Forest Ecology and Management 149, properties. Part I. Fibre length. Appita Journal 14, 168–178. 235–240. Yang, S., Lu, L., Ni, Y., 2006. Cloned poplar as a new fiber resource for the Chinese Mortha, G., Sarkanen, K.V., Gustafson, R., 1992. Alkaline pulping kinetics of short- pulp and paper industry. Pulp and Paper Canada 107 (2), 34–37. rotation, intensively cultured hybrid poplar. Tappi Journal 75 (11), 99–104. Zhu, L., Li, J., Bao, W., Sun, D., Julong, T., 2005. Influence of ages and species of fast- Nimz, H.H., Tschivner, V., Roth, M., 1983. In: Proceedings of the International growing poplar on alkaline peroxide mechanical pulping. Zhongguo Zaozhi 24 Symposium on Wood and Pulping Chemistry, vol. 1. Japan Tappi, Tokyo, p. 90. (1), 10–12.