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For the stability of composite fibre spinning, the difference in and distribution of the polymer melt velocity during the spinning are among the factors of importance. Based on the basic equation for the control of composite spinning dynamics, boundary conditions are identified and reported in this paper. A mathematical model for the symmetric and asymmetric distribution of the melt flow velocity in the microhole of the spinneret of the composite spinning assembly was developed. The accuracy of the mathematical model was also ascertained. It gives a theoretical basis for the designing of a composite spinning assembly. [ABSTRACT FROM AUTHOR]

The pigment coating of paper is usually performed to enhance the physical properties of paper and its printability. The coating generally makes paper whiter, brighter and more opaque. The properties of the coated paper depend, among others, on the porous structure of the coating developed, which is determined by the pigments, binders and their reactions. The influence of the type and quantity of coating components and ink absorption into the coating layer was studied in this work. Printing ink penetration was measured using a Penetration Dynamic Analyser with a HVL module (High Viscous Liquid). The evenness of liquid penetration into paper was measured using a Penetration Dynamic Analyser with a PEA module (Print Evenness Analyser). Results obtained indicate that all three variables - coating pigment type, latex dose and ink type - may have an equally strong influence on liquid and ink penetration, and thus on print quality. [ABSTRACT FROM AUTHOR]

The article analyses the effects of paper moisture content on energy absorbed during its tensile testing in the range of moisture equilibrium obtained during paper air conditioning at a temperature of 23 °C. To predict changes in breaking energy caused by changes in moisture content, two calculation methods were proposed. The methods were verified on the basis of laboratory tests and calculation results, and their practical usefulness was confirmed. [ABSTRACT FROM AUTHOR]

The flame retardancy of the mixture of hexa(N-hydroxymethyl)amidocyclotriphosphazene and partially methylated melamine formaldehyde resin (HHMATP/PMMM) in paper was proposed by limiting oxygen index measurement (LOI), the vertical burning test and cone calorimetry test (CCT). In our research, the LOI of washed FR-paper could still be up to 33.5%; the after flame time, and burning time were reduced to 4.8 s & 0 s, and the char length was only 12.0 mm. While the results of CCT imply that compared with non-flame retarded paper, the heat release rate (HRR) of FR-paper with HHMAPT/PMMM increases gently; the mass loss becomes significantly slow, and the prolonged maximum heat release rate (PHRR), average heat release rate (MHRR), average effective heat of combustion (MEHC) and total heat release (THR) drop greatly. According to the experimental results, HHMATP/PMMM has not only excellent flame retardancy in paper but also good water resistance, with HHMATP/PMMM playing a flame retardant role mainly by means of the condensed phase mechanism. [ABSTRACT FROM AUTHOR]

In this paper, the flame retardancy of hexaamidocyclotriphosphazene (HACTP) in paper was studied by limiting oxygen index measurement, the vertical burning test and cone calorimetry test. Meanwhile the mechanism was discussed by the analysis of residues obtained in the cone calorimeter test. The experimental results revealed that HACTP had excellent flame retardancy in paper. [ABSTRACT FROM AUTHOR]

A paper web produced under industrial conditions always exhibits an anisotropy in its mechanical properties measured in the machine and cross directions. Proper and fast information about current paper anisotropy would significantly increase the efficiency of web quality control systems and allow to produce paper with greater precision. The main objective of the work presented was to determine the possibility of measurement of paper anisotropy. The method proposed is based on the image analysis of the orientation and location of special markers -- luminescent fibres -- which were introduced to the structure of the paper. Studies have shown that the method of image analysis provides a detection of fibres with a satisfactory level of efficiency, thus allowing accurate examination of the anisotropy of the paper samples analysed. On the basis of experiments, it was also found that the method of image analysis proposed allows to detect fibres with an accuracy appropriate for the problem under consideration. The invention presented has already been registered in a Patent Office as submission no. P.411294. [ABSTRACT FROM AUTHOR]

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Copyright of Fibres & Textiles in Eastern Europe is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this work was to determine the optimal duration of free swelling for refined unbleached kraft pine pulp. Free swelling is the effect of water sorption by cellulose fibres without their simultaneous mechanical treatment (e.g. refining). The second purpose was to determine the possibility of improving the mechanical properties of paper by testing various combinations of refining and free swelling processes. The pulp SR value and water retention value (WRV) of the fibres were tested. As regards paper properties, the tensile index and tear index were tested. Based on the results obtained, it was found that for the pulp tested, refined to 35 °SR, the optimal time of free swelling was 70 min. It was also proved that the free swelling had a significant impact on both the WRV of fibres and the mechanical parameters of paper tested. For the scheme in which refining was followed by free swelling, a 7% increase in the tear index was obtained. However, an 11% increase in the tear index was attained for the scheme with three refining stages, followed by free swelling after each refining. [ABSTRACT FROM AUTHOR]

This research work presents a method for the determination of the limit of elasticity of paper considered as a variable dependent on stress and the time of its duration. For plane stress it was found that in the case of a low share of permanent strain in the total strain, we can assume that the highest value of its share appears on one of the principal axes of stress. Such an assumption allowed to use a one-dimensional rheological model to define the permanent range in a two dimensional state of stresses for paper. [ABSTRACT FROM AUTHOR]

Copyright of Fibres & Textiles in Eastern Europe is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fibres & Textiles in Eastern Europe is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Within the framework of research work carried out at the Institute of Papermaking and Printing, the Technical University of Łódź, Poisson's ratios were determined in a paper plane. This feature presents a simple and easy method how to determine this material constant. The method proposed for the determination of Poisson's ratio utilises the results of typical procedures used when defining physical properties, such as Young's modulus, paper density and the TSI (tensile stiffness index). For practical verification of the method proposed, the author tested papers for the production of corrugated board and compared the values of ratios obtained for the propagation velocity of sonic waves in the machine and cross directions. [ABSTRACT FROM AUTHOR]

The dyeability of bleached chemical pulps, bleached chemithermomechanical pulp and deinked pulp with anionic and cationic direct dyes was investigated. It was found that direct dyes may be used for mechanical and recycled pulps to reduce the cost of the paper manufacturing process by the application of cheaper semi-finished fibrous products. However, the colours attained differ from the colour of dyed chemical pulp. To obtain the required colour we needed larger amounts of dye, but in this way the savings obtained by using cheaper pulp grades may be wasted. [ABSTRACT FROM AUTHOR]

Within our research work we determined the Young's modulus distribution in the paper plane on the basis of results of tensile tests in selected directions. Using mathematical relationships valid for orthotropic materials, the moduli were calculated theoretically. The tensile stiffness orientation angle (TSA), and the TSO and TSI indices were also determined in order to define the deviations of the main axes of orthotrophy in the paper plane as determined by the machine and the cross directions. The calculation results were compared with measured values. They justified the conclusion that paper may be treated as an orthotropic material. [ABSTRACT FROM AUTHOR]

Copyright of Fibres & Textiles in Eastern Europe is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fibres & Textiles in Eastern Europe is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fibres & Textiles in Eastern Europe is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)