In-situ loading of calcium silicate in bleached bagasse fibers and its effect on pulp and paper properties

Mineral fillers are the second most important elements used in papermaking. Increasing filler content in writing and printing papers without decreasing the mechanical properties is always desired for enhancing the optical and printing properties and cost effective papermaking process. In this study, to increase the filler content in paper, calcium silicate was loaded by in situ precipitation on bleached bagasse fibers. The effect of reaction temperature on the loading and precipitation of calcium silicate on fibers was investigated using ash content measurement, XRD spectroscopy, SEM imaging and EDX analysis. Finally, the effect of treated pulp content on the physical and mechanical properties of pulp was investigated. Ash measurement results showed that calcium silicate precipitation in bleached bagasse fibers was achieved and the amount of calcium silicate loading increased with increasing the reaction temperature. XRD spectroscopy confirmed the formation of calcium silicate and calcium carbonate, and their precipitation in cell walls, lumen and interior spaces of the bleached bagasse fibers was confirmed by SEM imaging. The precipitated minerals on the fiber surface consisted of particles with various diameters. The EDX analysis confirmed the presence of silica and calcium in the treated fibers. With the constant basis weight of 80 g/m2, brightness and apparent density increased significantly, however the paper strength decreased by increasing the content of treated fibers in handsheet paper.