Does kraft hardwood and softwood pulp viscosity correlate to paper properties?

TAPPI Journal ◽  
2016 ◽  
Vol 15 (10) ◽  
pp. 643-651 ◽  
Author(s):  
ROBERT J. OGLESBY ◽  
HUMPHREY J. MOYNIHAN ◽  
RICARDO B. SANTOS ◽  
ASHOK GHOSH ◽  
PETER W. HART
Keyword(s):  
Physical Properties ◽  
Strength Loss ◽  
Strength Properties ◽  
Clear Correlation ◽  
Paper Properties ◽  
Physical Strength ◽  
Pulp Viscosity ◽  
Softwood Pulp ◽  
The Impact ◽  
Related Paper

The impact of commercially prepared, fully bleached pulp viscosity variation on handsheet physical properties was evaluated at different levels of pulp refining. Hardwood pulps from the same brownstock species mix, cooking parameters, and kappa numbers were processed through two different commercial bleach plants: one with a D0(EP)D1D2 sequence and the second with an OD0(EOP)D1 sequence. Additionally, a commercial softwood (predominately Scotts pine) brownstock pulp bleached by an OD0(EP)D1D2 sequence was employed in this study. Pulps with viscosities ranging from 14 to 21 mPa∙s were refined in a Valley beater to two freeness levels, and the associated handsheet physical properties were measured in this study. Over the pulp viscosity range of 14 to 21 mPa∙s, no clear correlation was found to exist between pulp viscosity and related paper physical properties. Finally, a series of laboratory prepared bleached pulps were purposely prepared under non-ideal conditions to reduce their final viscosities to lower values. Handsheets made from these pulps were tested in their unbeaten condition for physical strength properties. Significant and rapid strength loss occurred when the measured pulp viscosity dropped below 12 mPa∙s; overall strength properties showed no correlation to viscosity above the critical 12 mPa∙s value.

scholarly journals The Impact of Nano-Al2O3 on the Physical and Strength Properties as Well as on the Morphology of Cement Composite Crack Surfaces in the Early and Later Maturation Age

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4441
Author(s):  
Wioleta Iskra-Kozak ◽  
Janusz Konkol
Keyword(s):  
Fractal Dimension ◽  
Surface Profile ◽  
Fractal Dimensions ◽  
Cement Composite ◽  
Fracture Morphology ◽  
Strength Properties ◽  
Hardened Cement ◽  
Physical Strength ◽  
Binder Ratio ◽  
The Impact

This article presents the effect of aluminum nanoxide on the physical, strength and structural properties of cement mortars. The mortars were made with a water to binder ratio of 0.5 and a binder to sand ratio of 1:3; and 1%, 2%, 3% and 4% of aluminum nanoxide, respectively, were used by cement weight. First, the consistency of nano-Al2O3 mortars was tested. Next, after 7 days of sample maturation, compressive and flexural strength tests were carried out and continued after 28 and 90 days of the maturing of the mortars. The best test results were obtained for mortars with the addition of 1% aluminum nanoxide, the compressive strength of which increased by about 20% compared to the reference mortars. The water absorption and rising capillary tests as well as SEM observations were also performed. Another aim of the article is the analysis of the fracture morphology of nano-Al2O3 modified mortars. It is assumed that a change of the microstructure of the hardened cement paste affects not only the properties of the modified mortars but also the roughness of the fractures formed as a result of the destruction of the surface. Roughness analysis was performed with methods and tools relevant to fractal geometry. The fractographic analysis showed a significant influence of the modifier in the form of nano-Al2O3 on the values of fractal dimensions. The lowest values of the fractal dimension D and the fractal dimension of the DRP roughness profile of the fracture surface profile lines were obtained for nano-Al2O3 modified mortars. The conducted research proved the fractal dimension to be a parameter extremely sensitive to modifications of mortar composition as well as changes related to the maturation time.

Biobleaching: An eco-friendly approach to reduce chemical consumption and pollutants generation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Amit Kumar
Keyword(s):  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Strength Properties ◽  
Pulp And Paper ◽  
Pulp Fiber ◽  
Pulp Fibers ◽  
Physical Strength ◽  
Enzyme Pretreatment ◽  
Organic Halides ◽  
Pulp Viscosity

AbstractThe pulp and paper industry is known to be a large contributor to environmental pollution due to the huge consumption of chemicals and energy. Several chemicals including H2SO4, Cl2, ClO2, NaOH, and H2O2 are used during the bleaching process. These chemicals react with lignin and carbohydrates to generate a substantial amount of pollutants in bleach effluents. Environmental pressure has compelled the pulp and paper industry to reduce pollutant generation from the bleaching section. Enzymes have emerged as simple, economical, and eco-friendly alternatives for bleaching of pulp. The pretreatment of pulp with enzymes is termed as biobleaching or pre-bleaching. Different microbial enzymes such as xylanases, pectinases, laccases, manganese peroxidases (MnP), and lignin peroxidases are used for biobleaching. Xylanases depolymerize the hemicelluloses precipitated on pulp fiber surfaces and improves the efficiency of bleaching chemicals. Xylanase treatment also increases the pulp fibrillation and reduces the beating time of the pulp. Pectinases hydrolyze pectin available in the pulp fibers and improve the papermaking process. Laccase treatment is found more effective along with mediator molecules (as a laccase-mediator system). Biobleaching of pulp results in the superior quality of pulp along with lower consumption of chlorine-based chemicals and lower generation of adsorbable organic halidesadsorbable organic halides (AOX. An enzyme pretreatment reduces the kappa number of pulp and improves ISO brightness significantly. Better physical strength properties and pulp viscosity have also been observed during biobleaching of pulp.

Mg(OH)2 Partially Substituted Alkaline Peroxide Mechanical Pulping of Poplar

2012 ◽  
Vol 443-444 ◽  
pp. 850-854
Author(s):  
Fan Gong Kong ◽  
Chen Fu Li ◽  
Wei Zhang ◽  
Shou Juan Wang ◽  
Lin Wei
Keyword(s):  
Optical Properties ◽  
Physical Properties ◽  
Average Length ◽  
Fiber Quality ◽  
Quality Analysis ◽  
Economic Returns ◽  
Paper Properties ◽  
Physical Strength ◽  
Alkaline Peroxide ◽  
The Cost

Paper properties, including physical properties and optical properties, fiber quality analysis and COD in the pulp effluent were used to investigate the effects of substituting Mg (OH)2 for NaOH on the properties of poplar APMP in this paper. The results from fiber quality analysis showed that increasing the substitution levels of Mg (OH)2 for NaOH in the poplar APMP could increase the content of fiber fines,the pulp had shorter average length,and levels of kinking and curl reduced.The results of paper properties analysis ,including physical properties and optical properties ,showed that the bulk and light scattering coefficient of handsheets could be improved,while the physical strength and brightness couled be decreased after using Mg (OH)2.The research for COD in the pulp effluent showed that it could reduce content of COD in the pulp effluent after substituting Mg (OH)2 for NaOH on the properties of poplar APMP,so that clean production can come true easierly,while it could retrench the cost of production and yield good economic returns.

The Impact of Lignin Content on Paper Physical Strength of CTMP

2011 ◽  
Vol 236-238 ◽  
pp. 1242-1245
Author(s):  
Ben Ping Lin ◽  
Bei Hai He ◽  
Guang Lei Zhao
Keyword(s):  
Lignin Content ◽  
Strength Properties ◽  
Paper Strength ◽  
Fiber Morphology ◽  
Burst Strength ◽  
Physical Strength ◽  
The Impact ◽  
Linear Correlations ◽  
Total Lignin ◽  
Total Lignin Content

The research reported here gives some new insights into the influence of lignin content on paper strength properties. The relative amount of total lignin in CTMP was varied by using multistage ClO2 bleaching method. Few differences were observed in fiber morphology charcteristics of CTMP during ClO2 treatments. Linear correlations greater than 99% were found between total lignin content and paper strength properties. The influences of lignin content on Scott bond and tensile strength were greater than that of tear and burst strength.

Multistage fiber fractionation of softwood chemical pulp through smooth-hole screen cylinders and its effects on paper properties

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 259-267 ◽  
Author(s):  
S. JUNAID S. QAZI ◽  
MASITA MOHAMAD ◽  
JAMES A. OLSON ◽  
D. MARK MARTINEZ
Keyword(s):  
Physical Properties ◽  
Strength Properties ◽  
Operating Conditions ◽  
Raw Material ◽  
Optimum Operating ◽  
Aperture Size ◽  
Fractionation Process ◽  
Small Aperture ◽  
Paper Properties ◽  
Fiber Fractionation

Pressure screens are used to fractionate fibers on the basis of aspect ratio to obtain high value longfiber rejects and less desirable fines-rich accepts. Fiber fractionation is more practical and of maximum economic and commercial benefits when a mill can make use of all obtained fractions. We have demonstrated the potential of upgrading the reject fraction through a multistage fractionation process of a northern bleached softwood kraft pulp while isolating the remaining low-value pulp to be used as a raw material for a novel fiber-based product. The optimum operating conditions such as volumetric reject ratio, Rv; aperture velocity, Vs; and screen aperture size to carry out efficient fractionation were determined for the screens with 0.5-mm, 0.8-mm, and 1.0-mm apertures. This work shows that a high fines percentage in the accept fraction and increased fiber length in the reject fraction can be obtained when operating the pressure screen at a higher Rv and lower Vs using the screen cylinder with the small aperture size (0.5 mm). Feed and fractionated streams of pulp were used to study the effects on the physical properties of paper. Handsheets were made for strength properties of the unfractionated and fractionated pulps for comparisons. Significant improvements in the physical properties were observed after the removal of fines.

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.

Chemical, anatomical, and technology aspects of Eucalyptus benthamii and Eucalyptus dunii for use in an integrated pulp and paper mill

TAPPI Journal ◽  
2015 ◽  
Vol 14 (2) ◽  
pp. 73-81 ◽  
Author(s):  
GISELY SAMISTRARO ◽  
PETER W. HART ◽  
JORGE LUIZ COLODETTE ◽  
RICARDO PAIM
Keyword(s):  
Energy Levels ◽  
Black Liquor ◽  
Basic Density ◽  
Paper Mill ◽  
Frost Tolerance ◽  
Strength Properties ◽  
Kappa Number ◽  
Pulp Yield ◽  
Chemical Compositions ◽  
Physical Strength

Eucalyptus dunii has been commercially used in southern Brazil because of its relatively good frost tolerance and adequate productivity in the winter months. More recently, interest has grown in cultivating Eucalyptus benthamii Maiden & Cambage, which presents even superior frost tolerance compared to E. dunii and is highly productive as well. The quality of E. benthamii for pulp production is not yet proven. Thus, the chemical, anatomical, and technological aspects of pulp made from E. benthamii were compared with those of E. dunii for unbleached paper production. Samples of E. benthamii chips were obtained and analyzed for their basic density, chemical composition, higher heating value, trace elemental analysis, and chip size distribution. The chips were kraft cooked using conditions that produced a 74 ± 6 kappa number. The pulps were characterized for kappa number, yield, viscosity, and morphologic characteristics (e.g., length, wall thickness, and coarseness). Black liquor was analyzed for total solids, organics, inorganics, sodium sulfide, sodium hydroxide, and sodium carbonate. Brownstocks were beaten at five different energy levels in a Valley beater, and the physical strength properties of 120 g/m² handsheets were measured to develop a beater curve. The results of this study showed differences in delignification between the two woods and lower pulp yield for E. benthamii , which are related to their chemical compositions and basic densities. The E. benthamii studied in this work exhibited higher amounts of lignin and extractives, lower carbohydrate content, and lower basic density. However, cooking a blend of the two woods afforded good results in pulping and in physical pulp properties.

Multiple recycling of paperboard: Paperboard characteristics and maximum number of recycling cycles— Part I: Multiple recycling of corrugated base paper

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 631-638
Author(s):  
FREDERIC KREPLIN ◽  
HANS-JOACHIM PUTZ ◽  
SAMUEL SCHABEL
Keyword(s):  
Compression Test ◽  
Production Capacity ◽  
Strength Properties ◽  
Paper Properties ◽  
Corrugated Board ◽  
Laboratory Conditions ◽  
Base Paper ◽  
Study Results ◽  
Short Span ◽  
Multiple Recycling

Paper for recycling is an important fiber source for the production of corrugated base paper. The change in production capacity toward more and more packaging papers affects the composition of paper for recycling and influences the paper quality. This research project investigated the influence of the multiple recycling of five different corrugated base papers (kraftliner, neutral sulfite semichemical [NSSC] fluting, corrugating medium, testliner 2, and testliner 3) on suspension and strength properties under laboratory conditions. The corrugated board base papers were repulped in a low consistency pulper and processed into Rapid-Köthen laboratory sheets. The sheets were then recycled up to 15 times in the same process. In each cycle, the suspension and the paper properties were recorded. In particular, the focus was on corrugated board-specific parameters, such as short-span compression test, ring crush test, corrugating medium test, and burst. The study results indicate how multiple recycling under laboratory conditions affects fiber and paper properties.

MAGNESIUM ZK61A

Alloy Digest ◽  
1969 ◽  
Vol 18 (10) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Room Temperature ◽  
Heat Treating ◽  
Strength Properties ◽  
Casting Alloy ◽  
Chemical Company ◽  
Casting Alloys ◽  
Magnesium Casting

Abstract Magnesium ZK61A is a heat treatable sand casting alloy offering higher strength properties for room-temperature applications than other magnesium casting alloys. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Mg-67. Producer or source: The Dow Chemical Company.

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