Preparation Of Sulfonic Acid Hydroxypropyl Guar Gum And Its Application In The Papermaking

Guar gum was a natural green products. It had special physical and chemical properties. It was used as retention and drainage agent, reinforcing agent and paper binder in the paper industry. It had especially properties on the paper surface with adding Guar gum. It could improve surface strength and tensile strength of the paper. It could improve retention rate of fine fiberand filler. It could improve the bonding strength between layers of the board. However, dissolution rate of the natural guar gum was slow. The insoluble residue of it was high. The transparency of the solution of the Guar gum was poor. The stability of the solution of the Guar gum was not well. The scope of its application of it was limited greated. Therefore, the modification of guar gum was very necessary.The modification of guar gum mainly carried on the grafting reaction of single group in China now. The modified products of guar gum with several groups was only a few in the same position. The modification of anionic guar gum was mainly carboxymethyl substituents. Sulfonic acid as a novel anionic groups in the modification of guar gum was applied very seldom.In this paper, sulfonic acid hydroxypropyl guar gum(SHGG) synthesis were discussed. SHGG was prepared by a wet process based on reaction of guar gum and sodium 3-chloro-2-hydroxy propanesulfonate with an alkali catalyst. First sodium 3-chloro-2-hydroxy propanesulfonate was synthetized by the reaction of the epichlorohydrin and sodium bisulfite.Then SHGG was synthetized by the reaction of guar gum and sodium 3-chloro-2-hydroxy propanesulfonate.The reaction time, the reaction temperature and reactant ratio were discussed in the preparation of the sodium 3-chloro-2-hydroxy propanesulfonate. The synthesis process was optimized. The optimized conditions was the epichlorohydrin was added into the sodium bisulfite about 1.5 hour. The reaction temperature was controled about 85 degrees. The reaction time was about 2 hour. The ratio of 1:1.4 of epichlorohydrin and sodium bisulfite dosing was well. The product yield was about 82.5% in the optimized conditions.Alkaline catalyst, the reaction temperature, the reaction time, the dosage of sodium 3-chloro-2-hydroxy propanesulfonate were discussed in the preparation of the SHGG. The synthesis process was optimized. The optimized conditions was that guar gum was about 60g.The reaction temperature was about 60℃.The reaction time was about 3hour.The sodium hydroxide was about2.5g.The sodium 3-chloro-2-hydroxy propanesulfonate was about 3g. In the optimized conditions, the insoluble residue was about 5.34% and the apparent viscosity was about 792mpa.s. The spectrograms of IR, SEM, NMR,XRD,DSC testified that the synthesis was able to be completed. The effects of SHGG aqueous solution, including electrolyte added, acidity, substitution degree and concentration, were investigated to the rheology properties of SHGG. And the structure of SHGG product was analyzed. The results showed that SHGG aqueous solution had the behaviors of typical polymerizing-electrolyte. The viscosity of SHGG aqueous solution reduced with the concentration of electrolyte added increased. With the acidity increased, the apparent viscosity reached the maximum, and then it began to decrease, but the tendency became gentle. Additionally, the sensibility of SHGG aqueous solution to acid is better than that to alkali. The insoluble residue and the apparent viscosity reduced following the substitution degree increased. The apparent viscosity reduced following the shearing rate increased.It blended SHGG with aluminum sulfate together. The effects of filler retention rate effect and paper strength were investigated as papermaking additives. It were relatively well when aluminum sulfate was about 0.6% (relative to the absolute dry pulp) and the modification of anionic guar gum was about 0.25% ( relative to the absolute dry pulp). The retention rate increased by approximately 40% compared with he blank sample.