Fibre properties, paper

In chemical pulping, a significant part of the hemicelluloses is dissolved from the fibres into the pulping liquor. The rest remains in the fibre or is adsorbed into it, significantly affecting the properties of the cellulose fibres or paper produced... 

The nature of the bonds between cellulosic fibres in paper has been the subject of some controversy over many years. The early and now largely discredited view was that paper derived its strength merely from mechanical entanglement of the fibres. However, experiments in which paper is formed from non-aqueous solvents produce sheets with very poor strength properties and have thus tended to disprove this conjecture. In the mid-1950s deuteration experiments were carried out which demonstrated that of the order of 0.4-2% of all hydroxy groups are additionally bonded in paper as compared with the unbonded fibres. This observation led to the view that... 

Effect of Relative Humidity on the Surface Area of Paper. Virtually all the physical and mechanical properties of fibres and paper vary strongly with moisture content, and it would be expected that surface properties should also be sensitive to relative humidity. Little work has been published on the effect of moisture on the surface properties of fibres and paper. As a starting point, it may be noted that the basic property of any surface is its surface area. How does the surface area of a fibre or paper sheet change with relative humidity ... 

We apply the GC method to measurements of the surface properties of cellulosic fibres and paper as follows -... 

The adsorption isotherms provide information about the surface properties of the fibres or paper in the column. For example, the surface area in the column may be deduced from the shape of the isotherm according to the Brunauer-Emmett-Teller theory for multilayer adsorption (13, lJO. This theory gives the number of molecules, Nm, which forms a layer one molecule thick on the surface of the adsorbent. If the area, am, occupied by each vapour molecule adsorbed on the surface is known, then the total surface area, A, is simply given by... 

Together, these properties will influence retention, dewatering and paper strength developments, as well as liquid-paper interactions important in converting, printing and end use applications (see Sections 3-7 below). Some illustrative examples of the interrelationship between fibre treatment processes and fibre properties are given below. 

As discussed elsewhere in this chapter, soda delignification is a well-known process widely practiced for the production of pulp and high purity lignin from non-wood fibres [85]. The cellulose fraction could be converted to alcohol by saccharification and fermentation, particularly if the fibre properties of the feedstock are not the most suitable for paper manufacture. In addition to soda delignification, ammonia explosion and lime are among other alkaline processes being considered. 

Karenlampi P (1996) Strength and toughness of paper the effect of pulp fibre properties. Doctoral thesis, Helsinki University of Technology, Reports, Series A 4, Espoo Kettunen H, Nikanen KJ (2000) On the in-plane tear test. Tappi J 83(4) 1-6 Klungness JH, Caufield D, Sachs I, Tan F, Skyes M (1994) Fiber loading a progress report. 

Sama, E. Wlochowicz, A. Sama, M. Fibres Text. Eastern Fur. 2006, vol 14, 88-91. Zaman, R. Wunsch, D. C. Prediction of Yarn Strength from Fibre Properties from Fuzzy ARTMAP 1997, http //www.acil.ttu.edu/users/Raonak/papers/itc.htm Sette, S. Boullart, L. Langenhove, L. V. Text. Res. J. 2000, vol 70, 375-386. 

Olejnik, K. (2012). The effect of free swelling of refined cellulose fibres on paper mechanical properties. Fibres Text East Eur., 1(90),... 

Paavllalnen, L. (1991). Influence of morphological properties of softwood fibres on sulphate pulp fibre and paper properties, in Proceedings of the International Paper Physics Conference. Atlanta, GA TAPPI Press, pp. 383-95. 

J. Hikasa and T. Genba, Replacement for asbestos in reinforced cement products - Kuralon PVA fibres, properties, structure . Paper presented at the International Man Made Fibres Congress, Austrian Chemical Institute, Dornbirn, Austria, September, 1986. 

The mechanical properties of plastics materials may often be considerably enhanced by embedding fibrous materials in the polymer matrix. Whilst such techniques have been applied to thermoplastics the greatest developents have taken place with the thermosetting plastics. The most common reinforcing materials are glass and cotton fibres but many other materials ranging from paper to carbon fibre are used. The fibres normally have moduli of elasticity substantially greater than shown by the resin so that under tensile stress much of the load is borne by the fibre. The modulus of the composite is intermediate to that of the fibre and that of the resin. 

Direct dyes have only modest fastness to washing, which may be improved by after-treatments such as metal-complex formation (section 5.5.3) or by diazotisation of the dye on the fibre and further coupling of the diazonium salt with an insoluble coupling component (section 1.6.14). In addition to their use on cotton and viscose, direct dyes are important in the dyeing of leather. The cheapest members of this class are also used in the coloration of paper, since for this purpose fastness properties are largely irrelevant and price is all-important. 

The paper-making properties of all of these fibres are quite different from each other and also from wood. This is mostly due to the differing morphology and to some extent the differing chemistry of the fibre cells. The photomicrograph (Figure 1.2), shows a comparison between various non-woody fibre types. 

Figure 2.4 The effect offibrillar angle upon the mechanical properties of the fibres when they are used to make paper. 

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