Modification of the properties of pulp fibres for their application in the production of composite materials

Modification of sulphite pulp by the treatment with water-soluble silicon-containing compounds, i.e., silica sol and sodium water glass, was carried out. The interaction of cellulose with modifiers was studied over a broad range of modifier/pulp mass ratios using chemical analysis, XPS analysis and X-ray spectroscopy. The formation of silicon-containing networks on the surface of pulp fibres was established. It was shown that the treatment of pulp fibres with both modifiers under investigation influenced their hydrophilic properties. The formation of silicon-containing networks on the surface of pulp fibres during treatment with silica sol prevented swelling of fibres, lowered the limiting value of water adsorption and resulted in the narrowing of the hysteresis loop on the adsorption-desorption isothermal of the pulp. The effect of water glass on the hydrophilic properties of pulp depends on both its concentration in solution and duration of the treatment. Enhancement of the mechanical strength of single fibres after pulp' treatment with both modifiers was observed. Model fibro-cement sheets, by using of modified pulp, were obtained at laboratory and industrial scale. Testing of the sheets by conventional methods for reinforced fibre-cement sheets exhibited their applicability as a roof-covering material.