Kraft process

Abstract: Fibrillated kraft pulp impregnated with phenolic resin was compressed under an extremely high pressure of 100 MPa to produce high strength cellulose nanocomposites To evaluate how the degree of fibrillation of pulp fiber affects the mechanical properties of the final composites, kraft pulp subjected to various levels of refining and high pressure homogenization treatments was used as raw material with different phenolic resin contents It was found that fibrillation solely of the surface of the fibers is not effective in improving composite strength, though there is a distinct point in the fibrillation stage at which an abrupt increase in the mechanical properties of composites occurs In the range between 16 and 30 passes through refiner treatments, pulp fibers underwent a degree of fibrillation that resulted in a stepwise increment of mechanical properties, most strikingly in bending strength This increase was attributed to the complete fibrillation of the bulk of the fibers For additional high pressure homogenization-treated pulps, composite strength increased linearly against water retention values, which characterize the cellulose’s exposed surface area, and reached maximum value at 14 passes through the homogenizer

Abstract: Two laccase isozymes (I and II) produced by the white-rot fungus Trametes versicolor were purified, and their reactivities towards various substrates and lignins were studied. The N-terminal amino acid sequences of these enzymes were determined and compared to other known laccase sequences. Laccase II showed a very high sequence similarity to a laccase which was previously reported to depolymerize lignin. The reactivities of the two isozymes on most of the substrates tested were similar, but there were some differences in the oxidation rate of polymeric substrates. We found that the two laccases produced similar qualitative effects on kraft lignin and residual lignin in kraft pulp, with no evidence of a marked preference for depolymerization by either enzyme. However, the presence of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) prevented and reversed the polymerization of kraft lignin by either laccase. The delignification of hardwood and softwood kraft pulps with the two isozymes and the mediator was compared; either laccase was able to reduce the kappa number of pulp, but only in the presence of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate).

Abstract: Introduction and the Literature: Introduction to Papermaking. Introduction to the Literature. Abstract Indices. Technical and Trade Journals. Reference Books. Textbooks. Chemistry Reference Books. Other References. Wood and Fiber Fundamentals: Wood and Bark. Wood Chips and Sawdust. Wood Chip Preparation and Handling at the Pulp Mill. Solid Wood Measurement. Wood Chip Measurement. Wood Chemistry. Wood and Fiber Physics. Properties of Selected Wood Species. Nonwood and Recycled Fiber Considerations. Pulping Fundamentals: Introduction to Pulping. Mechanical Pulping. Chemi-Mechanical Pulping. Related Pulping Methods. Semi-Chemical Pulping. General Chemical Pulping. Soda Pulping. Kraft Pulping. Sulfite Pulping. OtherPulping Methods. Market Pulp. Kraft Spent Liquor Recovery: Chemical Recovery. Pulp Washing. Liquor Evaporation. Recovery Boiler. Cooking Liquor Regeneration--The Causticizing Process. Pulp Bleaching: Bleaching Mechanical Pulps. Measurement ofLignin Content. Bleaching Chemical Pulps. Refining and Pulp Characterization: Introduction to Refining. Refining. Pulp Characterization. Pulp Properties versus Performance. Paper and its Properties: General Grades of Paper. Specific Types of Paper. Basic Paper Properties. Physical Properties of Paper. Mechanical Properties of Paper. Chemical Analysis of Paper. Basic Optical Tests of Paper. Sheet Splitting of Paper. Stock Preparation and Additives for Papermaking: Fiber Preparation and Approach. Raw Materials. Functional Additives. Control Additives. Wet End Chemistry. Paper Manufacture:The Paper Machine. The Headbox. The Fourdrinier Wet End. Twin Wire Formers. The Cylinder Machine. The Press Section. The Dryer Section. Post DryingOperations. Paper Machine Broke System. Conversion. Coating. Fiber From Recycled Paper:Reycled Fiber Preparation. Recycled Fiber Recovery. Environmental Impact: Water Pollution. Water Quality Tests. Aqueous Effluent Treatments. Air Pollution.Air Quality Tests and Control. Solid Waste Disposal. U.S. Regulations. Metric and English Units and Unit Analysis: Metric Units. English and Metric Units. Unit Analysis. Introductory Chemistry Review: The Elements. Ionic and Covalent Bonds. Hydrogen Bonding. The Mole and Mass Percentage. Equivalency, Molarity, and Normality. Acids, Bases, and the pH Scale. The Law of Mass Action. Solubility Products. Oxidation-Reduction Reactions. Electrochemistry. Practical Aspects of Electrochemistry. Properties of Gases. Analytical and Coordinate Chemistry: Strong Acid--Strong Base Titrations. pH Properties of Weak Acid-Conjugate Base Pairs. pH Indicators. Titration of a Weak Acid With a Strong Base of Weak Base with a Strong Acid. Reduction-Oxidation Titrations. Colorimetric Analysis. Coordinate Chemistry. Miscellaneous Considerations. Calculations of Wood, Paper and Other Materials: Wood Moisture Content and Density. Pulpwood Measurement. Tensile Strength and Breaking Length of Materials. Paper Properties. Pulping Calculations: General Chemical Pulping Definitions. Kraft Liquor--Chemical Calculations. Kraft Liquor--Chemical Analysis. Specific Gravity and Viscosity of Kraft Liquors. Importance of Black Liquor pH. Kraft H-Factor andOther Process Control Equations. Sulfite Liquor Calculations. Sulfite Liquor Analysis. The Chemistry of Sulfur. Calcining Equations. Bleaching and Pulp Properties Calculations: Dilution Water Calculations. Chlorine Bleaching. Chlorine Dioxide. Chemical Analysis of Bleaching Liquors and Chlorine Equivalency. CSF Correction Equations. Computer Simulation of Fiber Cleaning Systems. Paper Maching Calculations. Properties of Dilute Pulp Slurries, Flocculation. Strength of Wet Fiber Mats. Fiber Physics.Polymer Chemistry: Introduction and Types of Polymers. Addition Polymers. Condensation Polymers. Molecular Weights of Polymers. Carbohydrate Chemistry: Nomenclature. Forms of Monosaccharides. Selected Reactions of Carbohydrates. Total Quality Management: Introduction to TQM and SPC. Statistical Process (Quality) Control, SPC, SQC. Statistical Process Control Tools. Implementing TQC and SPC. Miscellaneous Topics. Equations. Appendix -- Generating Random Data With a Normal Distribution.Colloid and Surface Chemistry: Colloid Chemistry. Polyelectrolytes. Surface Tension and Sizing. Surfactants. Foam. Emulsions. Light Scattering by Colloids. Appendix. Papermaking Chemistry: Polymeric Additives. Colloid Chemistry. Retention, Formation, & Drainage. Internal Sizing. Wet and Dry Strength. Monitoring Wet End Chemistry. Papermaking Chemistry Control. Other Considerations. Printing and the Graphic Arts: Letterpress. Lithography. Gravure. Screen Printing. Other Printing Methods. Halftone Printing. Color Printing. Common Aspects of Printing. Ink and Ink Application. Paper Properties and Printing. Specific Products. Computers and Printing. Bindery Operations. Appendix. Optical Properties of Paper: Behavior of Light Rays. Color. Tristimulus Systems. Blackbody Radiation and Other Light Sources. Kubelka-Munk Theory. Appendix. Wood and Fiber--Growth and Anatomy: Sample Preparation for Identification or Microscopy. Wood Variation. Silviculture and Wood Quality. Softwood Anatomy: Gross Anatomy of Softwoods. Microscopic Anatomy of Softwoods. Anatomy of Softwood Species. Non American Species. Hardwood Anatomy: Gross Anatomy of Hardwoods. Microscopic Anatomy of Hardwoods. Anatomy of Hardwood Species. Wood Fiber Anatomy and Identification: Fiber Analysis. Softwood Fiber. Hardwood Fiber. Nonwood Fiber Use in Pulp and Paper: Pulping Methods for Nonwood Fibers. Considerations for Nonwood Fiber Use. Other Fiber Types. Hydraulics: Flow of Liquids. Pump Basics. Positive Displacement Pumps. Centrifugal (Dynamic) Pumps. Valves. Hydraulic Power Systems. Troubleshooting Hydraulic Power Systems. Process Control: Sensors. Temperature Sensors. Mechanical Sensors. Controllers. Actuators. Corrugated Containers: Manufacture. Test Methods. Miscellaneous Topics: Viscosity and Surface Tension of Water from 1 to 100 deg.C. Vapor Pressure of Water From 0 to 280 deg.C. Properties of Air and Water. Water Conditioning. Boiler Feedwater Treatment. Corrosion. Safety Practices for Hazardous Chemicals. Transportation Safety. Operations Management. Process Simulation. Superabsorbency. Bearings. Electric Circuit Symbols. Appendix. Updates and Bibliography: General Pulp and Paper. Wood. Roundwood Properties. Wood Chemistry. Recycling and Secondary Fiber. Properties of Pulps. Mechanical Pulping. Chemical Pulping. Kraft Recovery. Bleaching. Fiber Physics and Preparation. Papermaking. Paper. Converting and Coating. Flexible Packaging.Environmental. Information Systems and Millwide Systems. Testing Methods. Answers to Selected Problems. Index.