The Importance of Xylan for the Strength Properties of Spruce Kraft Pulp Fibres

Holzforschung ◽  
2001 ◽  
Vol 55 (6) ◽  
pp. 639-644 ◽  
Author(s):  
C. Schönberg ◽  
T. Oksanen ◽  
A. Suurnäkki ◽  
H. Kettunen ◽  
J. Buchert
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Fracture Energy ◽  
Kraft Pulp ◽  
Fibre Length ◽  
Strength Properties ◽  
Total Charge ◽  
Pulp Fibres ◽  
Considerable Impact

Summary In this work the role of xylan in spruce kraft pulp fibres was investigated by selectively removing the pulp fibre xylan and also by sorbing xylan onto the pulp fibres. The effects of xylan removal and sorption on fibre properties were measured and the chemical composition of the fibres and also that of the selectively removed xylans was analyzed. According to the results the xylanase could act on both sorbed and native xylan located on accessible fibre surfaces. Xylan was found to affect the strength properties of handsheets. The location and the charge of xylan had a considerable impact on the formation of interfibre bonds. Scott Bond-values correlated with the amount of surface xylan on fibre surfaces, whereas tensile strength was affected by the total amount of xylan and particularly by the total charge of the fibres. The fracture energy was determined by the combined effect of interfibre bonding ability and effective fibre length.

scholarly journals Chemical composition and fiber properties of fast-growing species in Latvia and its potential for forest bioindustry

2017 ◽  
Vol 66 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Inese Sable ◽  
Uldis Grinfelds ◽  
Laura Vikele ◽  
Linda Rozenberga ◽  
Dagnija Lazdina ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Kraft Pulp ◽  
Lignin Content ◽  
Lodgepole Pine ◽  
Pulp Yield ◽  
Fine Content ◽  
Fast Growing ◽  
Pulp Fibres ◽  
Global Energy Supply ◽  
Fast Growing Species

AbstractBioenergy, including energy from wood, currently provides about 9–13% of the total global energy supply. Every fibre of fast-growing wood has a value for its potential use as a material in both pulp and paper and wood chemical industries. The aim of this study was to assess the chemical composition and fibre’s properties of fast-growing species in Latvia – aspen, hybrid aspen, lodgepole pine, poplar and willow. Results showed a variation of cellulose, lignin, extractives and ash contents among the species. Kraft pulp yield and amount of residual lignin were measured and properties of pulp fibres determined. Form factor and fine content in pulp were measured. Poplar and aspen wood had the highest content of cellulose, while lodgepole pine had the highest lignin content in wood and the longest kraft pulp fibres. Willow had 20% of fines in pulp. Individual results suggest the most suitable application of each species.

scholarly journals Comparison of two bar edge lengths of refining plates on the properties of American old corrugated container pulp during low consistency refining

BioResources ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 347-359
Author(s):  
Hui Cai ◽  
Zhaoyang Yuan ◽  
Guolin Tong ◽  
Xin Zhang ◽  
Hui Zhang
Keyword(s):  
Tensile Strength ◽  
Specific Energy ◽  
Lower Energy ◽  
Energy Input ◽  
Fibre Length ◽  
Strength Properties ◽  
Strength Development ◽  
Low Intensity ◽  
Plate Geometry ◽  
Length Reduction

Commercial American old corrugated container pulp (AOCC) boards were used as the starting material for repulping and low consistency (LC) refining to investigate the effects of LC refining plate geometry on the fibre and strength properties of the generated pulp. Specific refining energy that ranged from 0 to 120 kWh/air-dried ton (ADT) of pulp was explored for the two bar edge lengths (BEL) of refining plate patterns, wide 0.99 km/rev BEL and interim 2.01 km/rev BEL. The results showed that fibre length, curl index, kink index, and pulp freeness decreased while fines content increased with increasing refining energy input for both of the two refining plates during LC refining. LC refining with 2.01 BEL plate at low intensity of 0.24 J/m showed less fibre length reduction and more tensile strength development than that obtained with 0.99 BEL plate at high intensity of 0.48 J/m when compared at the same specific energy. Moreover, to achieve the desired tensile strength of the AOCC pulp, lower energy was needed for the interim 2.01 BEL plate than the wide 0.99 BEL plate. Thus, the interim 2.01 km/rev BEL refining plate provided potential for saving refining energy to reach a desired tensile strength of AOCC pulp.

scholarly journals Softwood kraft pulp fines: application and impact on specific refining energy and strength properties

Cellulose ◽  
2020 ◽  
Vol 27 (17) ◽  
pp. 10359-10367
Author(s):  
Daniel Mandlez ◽  
Lukas Zangl-Jagiello ◽  
Rene Eckhart ◽  
Wolfgang Bauer
Keyword(s):  
Tensile Strength ◽  
Linear Relationship ◽  
Apparent Density ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Air Permeability ◽  
Research Interest ◽  
Paper Properties ◽  
Softwood Kraft Pulp ◽  
Breaking Length

AbstractAlong with the emergence of micro and nanofibrillated celluloses and their application in papermaking, the influence of the so called fines fraction of pulps on both process and product properties has received increasing research interest in recent years. Several researchers have experimented with primary and/or secondary pulp fines to assess their effects on paper properties with not always consistent results. Our work focuses on the targeted application of the primary fines fraction of an unbleached softwood kraft pulp. The primary fines are separated from the pulp to be subsequently added to achieve blends of $$5\%, 9\%$$ 5 % , 9 % and $$12\%$$ 12 % primary fines content. These blends were then refined in a PFI mill to evaluate the effect of the primary fines on refining as well as on paper properties of hand sheets prepared from these pulps. It is shown that the addition of primary fines enhances tensile strength in the unrefined and slightly refined state, while the maximum tensile strength of the highly refined reference pulp is not increased. A slightly increased dewatering resistance (Schopper Riegler) at comparable air permeability (Gurley) for a given tensile strength was also observed. The linear relationship between tensile index and apparent sheet density seems to be affected in the unrefined and slightly refined state where the breaking length of the fines enriched samples is higher for a given apparent density.

scholarly journals Pulping of different parts of whole green jute (C. Capsularies) plant by Kraft process

2013 ◽  
Vol 48 (2) ◽  
pp. 105-108
Author(s):  
MR Alam
Keyword(s):  
Chemical Composition ◽  
Kraft Pulp ◽  
Energy Requirement ◽  
Strength Properties ◽  
Pulp Yield ◽  
Cellulose Content ◽  
Bottom Part ◽  
Kraft Process ◽  
Refining Operation ◽  
Different Parts

The chemical composition of the top, middle and bottom part of green jute plant (GJP) are not alike, thus the yield and strength properties of the pulp produced may vary if these are pulped separately. The alpha -cellulose content increases, whereas hemi-cellulose, lignin, ash and extractives decrease from top to bottom part of GJP. The Kraft pulp yield and strength properties increases (except tear) from top to bottom part of GJP. The pulp produced from GJP was found to undergo rapid beating in comparison to those of muli bamboo, jute cuttings. This indicates less energy requirement during refining operation of the GJP pulp. Low extractive (pectin) and high alpha-cellulose is favorable for pulping. Bangladesh J. Sci. Ind. Res. 48(2), 105-108, 2013 DOI: http://dx.doi.org/10.3329/bjsir.v48i2.15740

Fibre properties of Norway spruce of different growth rates grown under birch shelterwoods of two densities

2000 ◽  
Vol 30 (3) ◽  
pp. 487-494 ◽  
Author(s):  
Göran Bergqvist ◽  
Urban Bergsten ◽  
Bo Ahlqvist
Keyword(s):  
Growth Rate ◽  
Norway Spruce ◽  
Kraft Pulp ◽  
Coniferous Forest ◽  
Fibre Length ◽  
Strength Properties ◽  
Kraft Pulping ◽  
Strong Negative Correlation ◽  
Fibre Properties ◽  
The Difference

The effects of birch shelterwood density (0, 300, and 600 trees/ha) and growth rate on fibre and pulp properties of Norway spruce (Picea abies (L.) Karst.) understorey (growing at 1500 trees/ha) were evaluated for a trial in the boreal coniferous forest, 58 years after establishment of the stand and 21 years after establishment of the trial. Microdensitometry was used to record variations in wood density, whereas fibre properties and kraft pulp strength properties were measured on laboratory-made batches of unbleached kraft pulp. The main conclusion of the investigation is that a birch shelterwood has only a minor influence on the wood and fibre properties of sheltered Norway spruce and that the resulting consequences for kraft pulping are moderate. Length-weighted mean fibre length was significantly affected only by growth rate. It was 1.75 mm, or 6-13% lower, for trees showing a low growth rate than for all other trees. Tensile index was already high before refining, 85-95 Nm g-1, and the increase due to beating was similar for all shelterwood densities and growth rate classes. At 2000 beating revolutions, there was a strong negative correlation between tear index and the proportion of fibres shorter than 0.20 mm. The volume of wood required to produce 1 t of kraft pulp was almost identical, 5.4 ± 0.1 m3 t-1, for sheltered and unsheltered spruce. Norway spruce growing without shelter produced more pulp per hectare in all fibre length classes, but the difference was greatest, 56-59% compared with sheltered spruce, for the longest fibres (i.e., longer than 3 mm).

Fibre characteristics and paper properties of formic acid / peroxyformic acid birch pulps

1997 ◽  
Vol 12 (4) ◽  
pp. 237-243 ◽  
Author(s):  
Anu Seisto ◽  
Krisriina Poppius-Levlin
Keyword(s):  
Tensile Strength ◽  
Formic Acid ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Kappa Number ◽  
Strength Development ◽  
Paper Properties ◽  
Fibre Breakage ◽  
High Degree ◽  
Peroxyformic Acid

Abstract The fibre and paper properties of nine unbleached formic acid / peroxyformic acid (MILOX) pulps with kappa number 6-20 were studied and compared with a kraft pulp with kappa number 20. The degree of deformation was greater in the MILOX fibres, affecting the paper properties of the MILOX pulps. The large number of curl and kinks in the MILOX fibres were probably caused mechanically. The MILOX fibres showed greater conformability, resulting in higher paper density. The defects in the MILOX fibres were apparently so severe as to cause fibre breakage during PFI beating of the pulps. As a result of both fibre deformation and breakage, the tensile strengths of the MILOX pulps were lower than that of the reference kraft pulp, and tensile strength development during beating was slower. The tear strength of the best MILOX pulp was lower than that of the kraft pulp when compared at the same tensile index. Fibre deformation in both MILOX and the kraft pulp increased during bleaching. The kinks in the fibres were possibly set into position, giving the bleached MILOX pulps poorer bonding ability and lower paper density. A high degree of fibre defo~mation had the same effect on the tensile strength development of the bleached MILOX pulps as it did in the unbleached state. The light scattering properties of the MlLOX pulps were better than those of the kraft pulp, possibly due to the higher fines content of the MILOX pulps. The results indicate that more attention should be given to mechanical treatments during MILOX pulping in order to bring the strength properties closer to those of kraft pulp.

scholarly journals High strength paper from high yield pulps by means of hot-pressing

2020 ◽  
Vol 35 (2) ◽  
pp. 195-204
Author(s):  
Tove Joelsson ◽  
Gunilla Pettersson ◽  
Sven Norgren ◽  
Anna Svedberg ◽  
Hans Höglund ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Hot Pressing ◽  
Kraft Pulp ◽  
High Strength ◽  
Strength Properties ◽  
High Yield ◽  
Thermomechanical Pulp ◽  
Wet Strength ◽  
Chemical Pulp ◽  
Bleached Kraft Pulp

AbstractThe hypothesis is that it should be possible to modify papermaking conditions in line with the softening properties of high yield pulp fibres and achieve similar strength properties to conventional chemical pulp based paper. We therefore investigated the rheological and physical properties of high yield pulp based papers during hot-pressing. Our results confirm that increased temperature combined with sufficient pressure enables permanent densification by softening of lignin, producing very high tensile strength. This treatment also significantly improved the wet tensile strength in comparison to bleached kraft pulp without using wet strength agents. The high yield pulps used here were spruce based thermomechanical pulp, chemi-thermomechanical pulp, and high temperature chemi-thermomechanical pulp, and birch-aspen based neutral sulphite semi chemical pulp, with spruce-pine based bleached kraft pulp as reference. Rapid Köhten sheets of 150\hspace{0.1667em}\text{g}/{\text{m}^{2}} and 50 % dryness were hot-pressed in a cylinder-press at 20–200 °C, 7 MPa, and 1 m/min. The mechanical properties showed great improvements in these high yield pulp papers, with tensile index increased to 75 kNm/kg and compression strength index to 45 kNm/kg; levels close to and better than bleached kraft. Wet strength increased to 16 Nm/g compared to 5 Nm/g for bleached kraft.

SEM Study of Tension Wood Fiber Morphology and its Effect on Paper Properties

1977 ◽  
Vol 35 ◽  
pp. 308-309
Author(s):  
K. W. Robinson
Keyword(s):  
Tension Wood ◽  
Wood Fiber ◽  
Strength Properties ◽  
Fiber Morphology ◽  
Paper Properties ◽  
Pure Cellulose ◽  
Short Rotation ◽  
Hardwood Trees ◽  
Sem Study

Tension wood (TW) is an abnormal tissue of hardwood trees; although it has been isolated from most parts of the tree, it is frequently found on the upper side of branches and leaning stems. TW has been classically associated with geotropic alignment, but more recently it has been associated with fast growth. Paper made from TW is generally lower in strength properties. Consequently, the paper industries' growing dependence on fast growing, short- rotation trees will result in higher amounts of TW in the final product and a corresponding reduction in strength.Relatively few studies have dealt with the role of TW in the structure of paper. It was suggested that the lower strength properties of TW were due to a combination of factors, namely, its unique morphology, compression failures in the cell wall, and lower hemicellulose content. Central to the unique morphology of the TW fiber is the thick gelatinous layer (G-layer) composed almost entirely of pure cellulose.

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