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1.
Kenaf (Hibiscus cannabinus L.) is an annual plant which produces a very high fiber yield per hectare and has demonstrated to be a suitable material for
pulping. The crop conditions influence fiber production, but there is no information about their effect on pulp quality. The
aim of this work was to study the effect of kenaf varieties and crop conditions (watering dose and harvesting time) on sulfate
pulp quality. The study has been made on bast fiber sulfate pulps due to their high added value. The quality criteria were
fiber dimensions, chemical composition and pulp quality. Kenaf variety or crop conditions have significant effect on fiber
dimensions, holocellulose content, kappa number and breaking strength. To obtain high fiber yield and good delignified pulps
it is recommended to grow the Salvador variety and to employ advance harvesting.
Received: 20 January 1999 相似文献
2.
M. Sarwar Jahan 《Wood Science and Technology》2009,43(3-4):213-224
Dissolving pulps are the raw materials for the production of many different end-products. Jute is a very good source of cellulose. In this investigation, jute fiber was subjected to pulping in soda process in order to produce dissolving pulp under different prehydrolysis conditions and compared with prehydrolysed kraft pulp from jute. An increase of the prehydrolysis temperature or H2SO4 in prehydrolysis liquor increased the α-cellulose content and decreased the viscosity of pulp. The effect of ethylenediamine in soda liquor was also investigated when producing dissolving pulp. Jute fiber produced pulp having 90–97% α-cellulose. Ethylenediamine in soda liquor produced pulp of higher yield, viscosity and higher α-cellulose content than that of prehydrolysis soda or kraft pulp. The α-cellulose content and viscosity were increased with the increase of amine in soda liquor. The kappa number of dissolving pulp from jute was very low (9–5), which indicated that less bleaching chemicals are required for bleaching. The bleachability of soda-ethylenediamine pulp was lower than prehydrolysed soda and kraft pulp in ECF bleaching sequences. The bleachability of soda-ethylenediamine pulp was improved at the sacrifice of pulp yield when prehydrolysis was done prior to pulping. The alkali solubility S 10 and S 18 were 4–9 and 2–4%, respectively. 相似文献
3.
The bast and core of kenaf,Hibiscus cannabinus L., have markedly different chemical components and alkaline cooking responses. The bast had about double the hot-water extractives content and only about half the lignin content of the core. The core contained a large amount of hemicellulose, mostly composed of xylan. The lignin structures of bast and core were also quite different: The former had a significant abundance of syringyl structures. Evidence showed that the bast was much more easily delignified than the core. When the bast and core were cooked together in alkaline condition, the pulp yields at the same kappa number were higher than those of the individual pulpings of bast and core. The bast-core pulping gave a positive effect on the yield of bast pulp in the sodaanthraquinone and kraft pulpings. On the other hand, kenaf was abundant in the hot water extractives. These extractives consumed alkali during cooking to a relatively large extent but acted as a protector of hemicellulose and slightly increased the pulp yields.Part of this paper was presented at the 48th and 49th Annual Meetings of the Japan Wood Research Society, Shizuoka, April 3–5, 1998 and Tokyo, April 3–5, 1999 相似文献
4.
Agronomic properties (whole stalk yield, fiber length distribution, chemical composition) and whole stalk kraft pulp characteristics (total pulp yield, pulp fiber length distribution, pulp sheet strengths) were examined for kenaf (variety Zhehong 8310) at four plant populations, ranging from 135 000 to 405 000 plants/ha on arid hillside land at Anji, Zhejiang, China. For agronomic properties, the final whole stalk yield was higher as the plant population increased and as the altitude of the location on the slope decreased. Average fiber lengths of bast and core showed maxima at 225 000 plants/ha. Cellulose content increased as the plant population increased. For the kraft pulp characteristics of kenaf whole stalk, the total pulp yield was lower as the plant population increased, with the maximum difference about 1.3%. Sheet strengths and average fiber length attained maxima at around 225000–315000 plants/ha. The largest pulp strengths (breaking length, burst index, and folding endurance) were seen at a plant population of 225000 plants/ha, and the largest tear index was seen at a plant population of 315 000 plants/ha. When the agronomic properties and whole stalk kraft pulp characteristics were combined, a plant population between 225 000 and 315 000 plants/ha, which is a little higher than that of kenaf bast production for textiles, was selected as the optimum cultivated kenaf plant population for whole stalk kraft pulp and papermaking on arid hillside land in China. 相似文献
5.
Lignin characteristics of bast fiber and core in kenaf, bark and wood of paper mulberry and mulberry
The structural features of bast fiber and core lignins in kenaf (Hibiscus cannabinus), bark and wood lignin of paper mulberry (Broussonetia papyrifera (L.) Vent × Broussonetia kazinoki Sieb.) and mulberry (Morus bombycis) were characterized by alkaline nitrobenzene oxidation, ozonation and methoxyl group determination. Bj?rkman lignins were
isolated from bast fiber and core, and bark and wood fractions of the plant samples, and structural characteristics were investigated
by 1H NMR and 13C NMR spectroscopies. Kenaf bast fiber gave very high molar ratio of syringaldehyde to vanillin (S/V) of alkaline nitrobenzene
oxidation products, while methoxyl content was about the same as that of the core fraction. Results of 1H NMR and 13C NMR of Bj?rkman lignin suggested the presence of aliphatic fragments in lignins isolated from paper mulberry and mulberry
bark, but not in kenaf bast fiber. The lower yield of alkaline nitrobenzene oxidation products from bast fiber and bark might
be due to the higher content of condensed structure of lignin compared to core fraction. Total yield of erythronic (E) and threonic (T) acids of ozonation products and the molar ratio of erythronic acid to threonic acid (E/T) of the bast fibers and bark were lower than the corresponding core and wood fractions, suggesting that the contents of arylglycerol-β-aryl
ether intermonomer linkages in the bast fiber and bark lignin were lower than those of the core and wood fractions. Methoxyl
content of bark lignin was lower than the corresponding wood lignin. The methoxyl content of the extract-free kenaf bast fiber
was similar to that of the core fraction, while the values of paper mulberry and mulberry bark were about one-half of the
corresponding wood fractions, respectively. In bark lignins, the methoxyl contents of Klason lignin and Bj?rkman lignin from
bark were lower than those of the extract-free barks. This result suggests that the purity of Klason lignin and Bj?rkman lignins
of bark may be rather low. 相似文献
6.
Kenaf (Hibiscus cannabinus) plants are widely known for their contribution to the global and regional environment because of their ability to fix CO2. On the other hand, some scientists have doubts about CO2 fixation by kenaf and have misgivings about the effect of kenaf on the ecosystem. We have characterized the structural characteristics
of cell walls of bast fibers, cores, roots, and leaves of kenaf during the maturation of plants and investigated the rate
of photosynthesis. During maturation of the kenaf plant the cellulose (bast fiber 52–59%, core 44–46%) and lignin (bast fiber
9.3–13.2%, core 18.3–23.2%) contents increased significantly. The aromatic composition of the lignin of bast fiber was significantly
different from that of the core lignin and of other plants. The lignin of bast fiber appears similar to pure syringyl lignin.
Fixation of CO2 by kenaf plants and their contribution to the global environment are discussed. A significatly high rate of photosynthesis
of kenaf plants was observed compared to that of woody plants in Japan, but the amount of CO2 fixation depends on the characteristics of the plantation. If the kenaf was planted in high density, about twice as much
CO2 was fixed as was fixed by trees in a tropical rain forest.
Received: April 22, 2002 / Accepted: July 24, 2002
Acknowledgments This project was supported by the Science and Technology Agency (STA) fellowship of the Japan International Science and Technology
Exchange Center (JISTEC), which has been successfully applied by Dr. Shuji Hosoya, Forestry and Forest Products Research Institute.
We thank Dr. Toshio Sumizono and Mr. Masao Sakurai, Forestry and Forest Products Research Institute, for their kind help in
determining the rate of photosynthesis and cultivating the kenaf plants, respectively. We also express our appreciation to
Dr. Quang Hung Le, College of Agriculture and Forestry, Ho Chi Minh City, Vietnam for offering information about the cultivation
of kenaf at Thu Duc District, Ho Chi Minh City. 相似文献
7.
8.
世界木材制浆造纸工业技术发展趋势 总被引：3，自引：0，他引：3
林业是制浆造纸工业的基础，纸和纸板是高效益的林产品之一。随着科学技术的进步，制浆造纸工业已成为高技术工业。本文介绍了制浆造纸的原料问题和４种主要的制浆方法，并对制浆造纸工业技术的发展趋势进行了预测。 相似文献
9.
以杨木和白腐菌为研究对象,测定白腐菌预处理前后杨木化学组成与纤维形态的变化,找出合适菌株和最佳的预处理时间,进行硫酸盐法制浆前的预处理,比较制浆后浆料的卡伯值、得率、黏度和纸张的物理性能.结果表明:对木质素降解程度由大到小为香菇菌、云芝菌、杂色木云芝菌、脉射菌、佛罗里达侧耳和糙皮侧耳,香菇菌对综纤维素的降解程度最大,杂色木云芝菌的降解最小;预处理后,杨木纤维平均长度略有降低,纤维的长宽比得到了提高,壁腔比下降;与参照样相比,经脉射菌、杂色木云芝菌和佛罗里达侧耳预处理后制得的浆料,卡伯值降低、得率增加、黏度增加、脱木素选择性提高,纸张的撕裂指数和抗张指数均增加;经过香菇菌预处理后得到的浆料,虽然卡伯值降低、脱木素选择性增加,但是黏度和得率却在下降,纸张的撕裂指数和抗张指数减小.经过这4种白腐菌预处理后,纸张的耐折度和白度均大于对照. 相似文献
10.
Summary The behaviour of lignin-polysaccharide complex of spruce wood in soda pulping was studied by the characterization of lignin-saccharide fractions isolated from a series of soda pulps. The dioxane pulp lignins contain 8–14% of carbohydrates in which glucose was the predominant component. Its content increased with increasing degree of delignification indicating the formation of secondary lignin-carbohydrate linkage. Both glycosidic and ether type of bond between residual lignin and cellulose in pulp was proved by methylation analysis of the pulp dioxane lignin.The work was supported by the Slovak Academy of Sciences grant number 2/999389/92. 相似文献
12.
Acetic acid pulping of wheat straw under atmospheric pressure 总被引：4，自引：0，他引：4
Atmospheric acetic acid pulping of wheat straw was carried out. Pulping conditions and their effects on pulp properties were investigated in detail, and a comparison between acetic acid (AcOH) pulp and soda-anthraquinone (AQ) pulps of wheat straw was made of the chemical composition, strength, and fiber morphology of the pulps. Wheat straw was successfully pulped and fractionated into pulp (cellulose), acetic acid lignin, and sugars (monosaccharides from hemicellulose), making it easy to utilize them. It was found that among the pulping conditions the dosage of H2SO4 as catalyst was the most notable, and the extent and rate of delignification could be controlled by varying the amount of the catalyst. The results also showed that acetic acid pulp was quite different from soda-AQ pulp. About 70% of the ash or 90% of the silica in wheat straw were kept in AcOH pulp. The ash might function as filler and be beneficial to the printability of paper. It was known that many epidermal cells existed in AcOH pulp in bundles or in single cells. These ash-rich nonfiber cells seemed to hinder the bonding between fibers. AcOH pulp had lower strength than soda-AQ pulp, which might result mainly from the chemical damage of fibers caused by acid, not from the depolymerization of cellulose.Part of this paper was presented at the 65th Pulp and Paper Research Conference of Japan TAPPI, Tokyo, June 1998 相似文献
13.
对金沙江干热河谷不同年龄构树皮的化学、纤维特性与制浆性能进行研究.结果表明,构皮纤维长、木素含量低,纤维素含量高,纤维形态好,易于成浆.随着年龄的增大,低龄构皮化学组分稍有增大,但至6-7 a,灰分和木素含量增大,纤维素和硝酸-乙醇纤维素含量明显下降,不利于成浆;1%Na0H抽提物一直呈缓慢上升趋势,第6-7年达到最高;构皮纤维长度、长宽比及长纤维比例都随年龄的增长而增加,3-5 a增至最大,第6年后呈快速下降趋势.2-4年生构皮手抄片有较高的结合强度和耐折度,5-7 a后趋于稳定.因此,优质构皮纤维原料最佳收获期为2-5 a,综合经济效益考虑,纤维原料人工林培育最佳周期为2-3 a. 相似文献
14.
15.
竹子作为造纸原料的性能和潜力 总被引：22，自引：0，他引：22
竹子的纤维形态及化学组成表现出较好的制浆性能。从制浆性能及纸浆强度来评价，竹子是较好的造纸原料，仅次于针叶木，接近于阔叶木。随着造纸工业的发展，采用连续蒸煮和以氧及过氧化氢等无污染漂白新方法、新技术代替传统的竹子间歇蒸煮及常规含氯漂白的制浆技术是现代竹浆厂的目标。以竹代木，以减轻造纸工业对木材原料需求的压力，适应生态环境保护的要求为竹浆造纸提供了一个广阔的发展良机。 相似文献
16.
Kenaf composite panels were developed using kenaf bast fiber-woven sheets as top and bottom surfaces, and kenaf core particles as core material. During board manufacture, no binder was added to the core particles, while methylene diphenyldiisocyanate resin was sprayed to the kenaf bast fiber-woven sheet at 50 g/m2 on a solids basis. The kenaf composite panels were made using a one-step steam-injection pressing method and a two-step pressing method (the particleboard is steam pressed first, followed by overlaying). Apart from the slightly higher thickness swelling (TS) values for the two-step panels when compared with the one-step panels, there was little difference in board properties between the two composite panel types. However, the two-step pressing operation is recommended when making high-density composite panels (>0.45 g/cm3) to avoid delamination. Compared with single-layer binderless particleboard, the bending strengths in dry and wet conditions, and the dimensional stability in the plane direction of composite panels were improved, especially at low densities. The kenaf composite panel recorded an internal bond strength (IB) value that was slightly low because of the decrease of core region density. The kenaf composite panel with a density of 0.45 g/cm3 (one-step) gave the mechanical properties of: dry modulus of rupture (MOR) 14.5 MPa, dry modulus of elasticity (MOE) 2.1 GPa, wet MOR 2.8 MPa, IB 0.27 MPa, TS 13.9%, and linear expansion 0.23%. 相似文献
17.
Summary Delignification studies on 0.5 m sections of Douglas-fir earlywood tracheids pulped by soda, soda-anthraquinone (soda/AQ) and kraft pulping processes were performed by determining bromine concentrations in various morphological regions with SEM-EDXA technique. Soda/AQ pulping was much more selective in removing lignin from the middle lamella regions than either soda or kraft pulping. However, up to 50% delignification, more lignin was removed from the secondary wall by soda or kraft, compared to soda/AQ pulping. The kinetics of lignin removal in the various morphological regions were established. Addition of AQ and sodium sulfide resulted in an earlier transition from a slow initial to a rapid bulk delignification, particularly in the middle lamella, and in an enhanced bulk delignification in the secondary wall. Anthraquinone was also found to promote residual delignification in the secondary wall, where sodium sulfide was not effective. The opposite was observed for the bulk delignification in the middle lamella, where only sodium sulfide addition improved the rate significantly. The great differences observed in the bulk delignification rates between middle lamella and secondary wall in soda pulping as well as their response to additives suggest structural differences between middle lamella and secondary wall lignins.Paper No. 6712 in the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina. The paper, an excerpt from the Ph. D. dissertation of Shiro Saka, was selected for the second place Wood Award for 1980 cosponsored by Forest Products Research Society and the Kirby Forest Industries, Inc., Houston, Texas, and presented at the American Chemical Society Annual Meeting, Las Vegas, Nevada, August, 1980 相似文献
18.
Both of straight and inclining poplar clone 107 tree were selected for studying materials in this paper.The optimal pulping conditions was established by orthogonal experimental design both for normal wood and tension wood,and the quality of pulping and paper-making between normal wood and tension wood was compared with each other. Finally,potential application for improving paper quality of tension wood through increasing beating revolutions was discussed.The result showed that the optimal cooking condition for normal wood was alkali concentration 15%,the highest temperature 164℃,time at highest temperature 75 min,and for tension wood it was alkali concentration 13%,the highest temperature 160℃,time at highest temperature 40 min.Path coefficient of effect of alkali concentration both on pulp yield and kappa value was significant at different levels.By comparison between average result of normal wood and tension wood in quality of pulping and paper-making,it was found that tension wood had higher pulping yield and lower kappa value than normal wood. Furthermore,for all mechanical properties of paper, normal wood hold higher value than tension wood, and even near two times than tension wood,such as burst index and tensile index.However,difference of tear index was quite narrow.Result of one way ANOVA showed that difference of burst index and tear index between normal wood and tension wood was significant at the 0.001 level,of tear index was significant at the 0.05 level.Based on observation of cross surface of paper,it was assumed that contribution of gelatinous layer to rigidity of single fiber had hampered collapse and compression of fiber during paper formation,which is essential for exerting combination between fibers in paper.So, mechanical properties of tension wood paper were decreased accordingly.However,owing to high cellulose content of gelatinous layer,tension wood was easier to pulping than normal wood.Mechanical properties of tension wood paper could be improved by increasing beating revolutions, 相似文献
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20.
中国竹子资源丰富，分布广泛，发展竹材制浆造纸产业，对于缓解木浆原料短缺现状具有重要意义。根据对竹浆的理化性能分析，竹材是较好的造纸原料，竹材的纤维形态及化学组成表现出较好的制浆性能，仅次于针叶木，接近于阔叶木。从竹材应用于竹浆造纸的角度，综述了竹材的物理化学性能、现行的竹浆造纸工艺、竹浆造纸设备，并就竹浆造纸的发展潜力与发展方向提出了个性化观点，以期为探索绿色、低碳、环保的竹资源利用新途径，为开发高技术含量和高附加值竹产品提供借鉴，从而促进中国竹产业可持续发展。 相似文献