Arabian Journal of Chemistry (2017) 10 , S1059–S1066
King Saud University
Arabian Journal of Chemistry
www.ksu.edu.sa www.sciencedirect.com
ORIGINAL ARTICLE
Efficacy of dispersion of magnesium silicate (talc) in papermaking
Vipul Singh Chauhan a , Nishi Kant Bhardwaj b, *
a Department of Paper Technology, Indian Institute of Technology Roorkee – Saharanpur Campus, Saharanpur 247 001, India b Thapar Centre for Industrial Research & Development, Yamuna Nagar 135 001, India
Received 23 August 2012; accepted 15 January 2013 Available online 4 February 2013
KEYWORDS
Abstract The understanding of the dispersion chemistry of papermaking grade fillers is as impor- tant as their effect on paper. Magnesium silicate (talc) is one of the major fillers used for papermak- ing. It is hydrophobic and chemically inert. The dispersion chemistry of talc of different particle sizes was studied with wetting agent (non-ionic triblock copolymer) and anionic dispersant (sodium salt of polyacrylic acid). Both wetting agent and dispersant were added in talc slurry separately and in combination. The dispersion behavior was studied through measuring the Brookfield viscosity. The wetted and dispersed talc was also added to paper to understand its effect on papermaking pro- cess and paper properties. Wetting and dispersion changed the colloidal charge chemistry of talc making it more anionic which reduced the talc retention in paper. Lowering the particle size of talc significantly improved the light scattering coefficient (LSC) of paper and decreased its retention. Controlling colloidal charge of papermaking suspension with cationic polyacrylamide polymer helped in protecting the retention of talc without affecting the LSC of both filler and paper. ª 2013 Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
Dispersion; Magnesium silicate; Polyacrylic acid; Non-ionic triblock copoly- mer; Paper; Scattering coefficient; Retention
1. Introduction
ing papers because they increase the light scattering, opacity and brightness, and generally improve printing properties. The mineral fillers for acid papers are talc, hydrous kaolin, cal- cined kaolin, precipitated silica and silicates, and titanium diox- ide. For neutral and alkaline papers, layered magnesium silicate (talc), hydrous kaolin, calcined kaolin, ground calcium carbon- ate (GCC), precipitated calcium carbonate (PCC), silica and sil- icates, and titanium dioxide are used. The use of filler is important when opacity is needed at a low-basis weight; they are invaluable in packaging grades where low permeability is combined with opacity to protect food from light. The presence of fillers, however, affects fiber-to-fiber contact and reduces the paper strength (Wilson, 2006; Chauhan et al., 2012a). Other properties are improved rendering the paper useful for special
Paper consists of not only cellulosic fibers but also considerable amounts of mineral fillers. Fillers are highly desirable in print-
* Corresponding author. Tel.: +91 1732 292703; fax: +91 1732 292748. E-mail addresses: nishikant_bhardwaj@rediffmail.com, dydirector@ thaparpaperresearch.org (N.K. Bhardwaj). Peer review under responsibility of King Saud University.
Production and hosting by Elsevier
http://dx.doi.org/10.1016/j.arabjc.2013.01.012 1878-5352 ª 2013 Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
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