Papermaking Fibers Research Articles

Determination of Ferulic and p-Coumaric Acids in Wheat Straw and the Amounts Released by Mild Acid and Alkaline Peroxide Treatment

Ferulic acid (FA) and p-coumaric acid (PCA) are two major phenolic acids in a wide variety of graminaceous plants. Particularly, FA has been implicated in cross-linking cell wall polymers. In the present paper, the variations in FA and PCA contents of wheat straw upon various treatments relevant to the process of producing paper-making fibers were investigated. Wheat straw contained 0.48% FA and 0.42% PCA on the basis of dry material. Among them, of the total FA, 56% was esterified only and 44% was etherified. In contrast, >80% of the PCA was esterified only. In general, the phenolic acids had a high tendency to dissolve in hot water or alkaline peroxide solution, as compared to lignin. Nevertheless, the two-step pulping process, a mild acid wash followed by alkaline peroxide bleaching, removed <40% of FA and <20% of PCA. The phenolic acids remaining attached to the lignin might have an effect on the properties of wheat straw fibers made according to this method. Keywords: Ferulic acid; p-coumaric acid; lignin; wheat straw; alkaline peroxide bleaching

5501768 Method of treating papermaking fibers for making tissue

5501768 Method of treating papermaking fibers for making tissue

Pulping Characteristics ofEucalyptusProvenance Trials Grown in the Western Cape

SYNOPSIS For the purpose of Part I of this investigation, eight eucalypt species (irrespective of provenance), 12 years of age and grown along the northern slope of Stellenbosch mountain in the Western Cape were chipped, screened and pulped using the Kraft process. The pulps so obtained were compared with E. grandis pulp, cooked under similar conditions, since E. grandis pulp is known to be excellent papermaking fibre. The pulp evaluations revealed excellent strength development during beating in the case of the E. globulus, E. dunnii and E. nitens. These species also produced high screened yields with low percentages of rejects as well as acceptable strength values for burst, tear, and breaking length at a wetness of 38° SR and compared well with corresponding values obtained for E. grandis. In Part II (to follow) data on Kraft pulping characteristics as well as pulp strength properties of E. dunnii (three provenances), E. globulus (three provenances) and E. nitens (10 provenances) will be presented and ...

Poiseuille Medial Award lecture: from papermaking fibers to human blood cells.

Poiseuille Medial Award lecture: from papermaking fibers to human blood cells.

Motion of fluid-suspended fibres in a standing wave field

Under the influence of a stationary ultrasonic wave field, fluid-suspended fibres shorter than one-fourth of the acoustic wavelength migrate toward stable equilibrium positions and reorientate to stable equilibrium angular positions. Using optical monitoring of the suspension, acoustic layering and reorientation can be studied as a function of fibre dimensions. To explain some experimental results obtained with a dilute water suspension of paper-making fibres, a theoretical investigation of fibre motion and light scattering behaviour during ultrasonic excitation is required. This paper reports on some aspects of the mathematical model being developed. It is shown that acoustic layering and reorientation are dominant effects for long and short fibres, respectively.

Model Study of Paper Elasticity and Drying Restraints

ABSTRACTExperiments on laboratory paper sheets have indicated that under certain conditions the elastic modulus is inversely proportional to both the drying shrinkage and dimensional stability. Thus it appears that the elastic response of paper to mechanically and hygroscopically induced stresses is determined by the drying strain or shrinkage of the sheet. It is not clear, however, what effect the geometry of paper network and the properties of papermaking fibers have on the relationship between paper elasticity and drying restraints.We have developed a model for the study of the elastic properties of paper as a function of the drying shrinkage. The model is based on the assumption that there exists a unique relationship between the elastic properties and dried-in compression of fiber. As a consequence, the elastic properties of a fiber depend on its orientation relative to the principal axes of the paper sheet.The qualitative features obtained from the model calculations are consistent with experimental observations and independent of details of the elastic properties of fiber. It is clearly shown that no unique relationship exists between the drying strain and elastic modulus of the paper sheet. However, to a reasonable accuracy certain simple relatioships do exist that appear to be of general validity.

Multi-Use Botanochemical Crops, an Economic Analysis and Feasibility Study

Dwindling reserves and increasing costs of petroleum have brought the realization that agricultural production of substitutes may be both feasible and the best long-term alternative. Multi-use oil- and hydrocarbon-producing (botanochemical) crops, specially designed for an adaptive agricultural system, appear to offer potential for combining the production of both food and industrial raw materials with increased overall productivity. Processing methods are being developed for extraction of primary botanochemicals, i.e,. soluble polyphenols, whole-plant oils, and isoprene polymers that could serve as chemical feedstocks. The extractive-free residues are promising raw materials for papermaking fibers, animal feeds, fermentation substrates, chemical feedstocks, fuels, and soil amendments. Preliminary cost assessments of crop production, collection, and processing compared with projected produce values suggest that a new and radically different agricultural system would be economically attractive.

Fibre measurements of some aquatic species with a view to new sources of papermaking fibre

The ever-increasing demand for plant fibre sources has led to the study of novel plant forms. This is a preliminary study of some aquatic plants with a view to establishing their possibilities as fibre sources.

Relationships between velocity profiles and drag reduction in turbulent fiber suspension flow

AbstractAnalytical relationships between velocity profiles and flow resistance data are developed for suspensions of papermaking fibers in turbulent shear. The relationships apply to suspensions of synthetic fibers. The wall layer appears to be unaffected by the presence of fibers, and the cause of drag reduction can be attributed to the turbulent core region.

The Modification of Wool and Cellulose Fibers by Grafting

Abstract Grafting to fibers has been studied extensively since the early 1950s as a technique for modifying their properties. Extensive reviews are available on this general subject [l-41. Although the main emphasis has been with textile fibers, considerable work has also been carried out with paper-making fibers and on paper itself [l,5].

Measurement of Pulp Consistency by Ultrasonic Attenuation

Measurement of the attenuation of acoustic waves is suggested as a method for deducing the consistency of thin suspensions of papermaking fibres. Results obtained by a pulse method in the frequency range 1 to 6 MHz show that attenuation increases linearly with consistency. The measurements are in the range 0 to 2.5 wt. %, a range wh ich is not adequately covered by other methods of consistency measurement. The specific attenuation varies between samples. Values of the order of 20 dB/wt.% metre at 1 MHz are reported, increasing roughly as the square of frequency. The effects of temperature, wetness, additives, and entrained air are discussed.

Zeta potential measurements of fibres. D‐C. Streaming current method

AbstractStreaming current techniques have been extensively used in measurements of zeta‐potential, ζ, at the solid/liquid interface of capillary systems. In the case of porous, swelling and deformable materials, the application becomes less certain because of the complex geometry of the flow paths and interactions of neighboring electric double layers. The applicability of the equations developed by Goring, Biefer and Mason to papermaking fibres in various electrolytes is examined and found inadequate. An exponential form of the concentration function in the streaming current equation is proposed, IηL/pD = (Aζ/4π) exp(–Bc), and its reliability in evaluating ζ, is demonstrated. Factors affecting the parameter B are discussed.

Stresses exerted by water held in wet webs of paper-making fibres

Stresses exerted by water held in wet webs of paper-making fibres

Durability of Purified Wood Fibers Accelerated Aging Tests of Various Types of Paper-Making Fibers

Durability of Purified Wood Fibers Accelerated Aging Tests of Various Types of Paper-Making Fibers

Paper Technology An Elementary Manual on the Manufacture, Physical Qualities, and Chemical Constituents of Paper and of Paper-making Fibres

Paper Technology An Elementary Manual on the Manufacture, Physical Qualities, and Chemical Constituents of Paper and of Paper-making Fibres