Application of DSA to improve strength of thermomechanical pulp blended paper

A more efficient application of a dry strength agent (DSA) was investigated to improve the strength of thermomechanical pulp (TMP) blended paper. Strength improvement by DSA application was more effective for hardwood bleached kraft pulp (Hw-BKP) than TMP. The degree of strength improvement of DSA further increased with the increasing degree of refining of Hw-BKP. The strength of the paper was decreased by the fines fractionation of TMP, but the strength improvement efficiency of DSA for the fines fractionated TMP increased. In order to increase the strength of TMP mixed paper using DSA, it is expected that DSA should be adsorbed only to Hw-BKP with high strength improvement efficiency, not TMP fines. When the DSA was mixed with Hw-BKP before contact with other stocks, it was confirmed that the effect of improving the strength by the DSA is the best. The strength improving effect increased as TMP fines were removed. Therefore, to improve the strength of the paper containing TMP in Hw-BKP by adding a DSA, it is preferable to selective apply the DSA to Hw-BKP while blending only the fibers of TMP by fractionation.

Biorefining: the role of endoglucanases in refining of cellulose fibers

With an annual production of more than 400 million tons, paper is the main product of the largest biorefinery process industrially implemented. Enzymes have been used for pulp refining to dramatically reduce energy consumption. However, exact mechanisms related to the individual enzymes are hardly understood. Yet, this knowledge would be important to predict enzyme performance in industrial processes. Three commercial refining enzyme formulations showed different endoglucanase (1.25 nkat mg−1–13.7 nkat mg−1), β-glucosidase (0.57 nkat mg−1–1.34 nkat mg−1) and xylanase activities (1.78 nkat ml−1–62.1 nkat mg−1) on model substrates. Additionally, distinct amounts of reducing sugars from hardwood sulfate pulp were released. Endoglucases were purified from each formulation by using hydrophobic interaction and anion exchange chromatography and showed molecular weights from 20 to 55 kDa and specific activities ranging between 3.11 and 26.3 nkat mg−1 according to endoglucanase specific derivatized cellopentaose (CellG5). Refining trials of hardwood sulfate pulp were conducted using a PFI laboratory mill and fiber properties such as degree of refining or fiber length and properties of formed sheets like tensile index were monitored. Thereby, enzymes were dosed based on identical endoglucanase activity on CellG5. Enzyme formulations and purified endoglucanases led to an increase of the degree of refining of up to 47.9 [°SR] at 6000 PFI revolutions while the tensile index was improved by up to 76.0 Nm g−1. In summary, refining effects can be primarily attributed to endoglucanases indicating activity on CellG5 being a suitable parameter for enzyme dosing.

Implications of Allergic Reactions to Soybean Oil

Soybeans oil both cold-pressed and fully refined oils have been shown to contain proteins. Although most publications suggest that refined oils do not induce allergic reactions in sensitive individuals, adverse reaction to soy oil in an infant has been reported. Is used in cooking and food formulations. The presence of protein in soy oil depends on the degree of refining, as for other seed oils

THE ROLE OF FIBERS SURFACE IN DEVELOPMENT OF PAPERMAKING PROPERTIES OF TECHNICAL PULP IN THE REFINING PROCESS

The aim of this work was to determine the relationship between the values of the fiber specific surface and papermaking properties of the pulp that are changing in the refining process. Quality data on the status and quantitative data on the value of the fibers specific surface for softwood and hardwood kraft pulp with different lignin content and different degree of refining were obtained. When preparing samples was used technology of cryofixation and freeze-drying the wet laboratory samples. The SEM-images of the cellulose fibers surface in the state such as for the sheet forming, obtained on scanning electron microscope ZEISS "SIGMA VP". The SEM-images shows just noticeable difference in development of the fibers surface in the beating process. This is manifested in an increase in the number of microfibrils on the fiber surface. Quantitative data were obtained on the automatic analyzer of the specific surface magnitude ASAP. A visually apparent increase of the surface when beating technical cellulose confirmed quantitatively. The value of the specific surface area increased from 2 m2/g for cellulose after the dispergation into pulp of up to 4...6 m2/g after refining up to 60 °SR. Removal of lignin from cellulose promotes more intensive development of the surface during refining.For different kinds of pulp, similar dependences of physical-mechanical properties (interfiber bonding forces, bulk density, modulus of elasticity) of laboratory samples and specific surface data, which change during refining, are established.The main influence on the change in the structural-dimensional and elastic properties of paper during refining is exerted by an increase in the content of microfibrils on the outer surface of the fibers. The tightness of the correlation and the nature of the observed dependence depends on the wood species from which the cellulose is derived, on the lignin content of the samples, and on the drying method. For softwood pulp, the tightness of the relationship is higher than for hardwood pulp.

Based on CSP Technics, the Experimental Research of Rare Earth Steel Hot-Rolled Deformation Behaviors

Based on CSP technics, using Gleeble1500-D hot simulation machine, making the single, dual, multi-pass compression experiment of Q345B steel with rare earth Nd respectively, different deformation conditions influencing Q345B steel of recrystallization behavior and the microstructure evolution rule in the hot rolling process have been studied. The results show that: the single, dual-pass experiments of Q345B steel with rare earth Nd are according with general experimental rules. According to single, dual-pass results, we establish multi-pass compression project. In that project, the grain samples with rare earth element Nd are finer than others. It explains that appending rare earth Nd has the obvious function of refining grains. At the same time, the degree of refining grains is different in the different project. It explains that in order to obtain fine grains, we should choose feat technics. By contrast, we can educe that the grains are more fine and uniform in a project.

Using Ultrasound to Characterize Pulp Slurries With Entrained Air

The development of fast and practical methods for inspecting fiber suspensions is of great interest in the paper making industry. For process control and paper quality prediction, several elements of the refining process during paper making must be accurately monitored, including specific fiber properties, weight percent fiber (composition), degree of refining, amount of solids, and entrained air content. The results of previous ultrasonic studies applied to wood pulp provide guidance that ultrasound attenuation is information rich, and it does potentially provide a tool for consistency measurement. Ultrasound has the ability to penetrate dense suspensions such as wood pulp slurries. It is has been shown, in some studies, that ultrasound is sensitive to degree of refining. The effects of entrained air, additives, the origin and treatment of the fibers do however all influence the measured data. A series of measurements were made with hardwood and softwood slurries to evaluate the ability of measuring pulp consistency, solids, and entrained air. The attenuation through the slurry was measured as the ultrasound travels from one transducer through the slurry to the other. The measurements identified the presence of entrained air in the pulp samples. To better understand the effects of air, measurements were made at increasing pressures to show how increased pressure reduced the amount of air observed in the spectrum.

Identification of Cellulose Fibers Isolated from Reconstituted Tobacco

It is well known that the physicaI characteristics of natural fibers, particularly those of vegetable or cellulosic origin, can be controlled within well-defined limits by the chemicaI pulping methods and by the degree of refining to which they are subjected. It has been found that when such materials are subjected to a mild chemical treatment for the isolation of the cellulose, the isolated cellulose fiber, under microscopic analysis, has retained its physicaI identity despite the chemicaI exposures. This technique has been successfully applied to reconstituted tobacco as a means of identifying the source of the cellulose used in its manufacture. Not only can the source of the cellulose be determined as being from tobacco or wood, but the degree of refining to which these constituents were subjected prior to conversion into the reconstituted product can be easily ascertained. Photomicrographic proof for the validity of these statements is presented