Cleaner approach for improving the papermaking from agro and hardwood blended pulps using biopolymers.

Abstract Due to rapid deforestation, the paper industry is facing problems like shortage of forest based raw materials, cost increment and negative effects on the environment including increasing air, water and soil pollution. In India, agro residues utilized in stubble burning could be used as a sustainable fiber resource for papermaking, but the paper made from these possesses poor strength properties. Considering the multiple advantages of using agro residues and weak strength properties of the paper made from these, this study was conducted. The effect of blending hardwood pulp and agro pulp with cationic starch or chitosan at wet-end of papermaking with and without subsequent surface sizing using oxidized starch was explored. As a wet-end additive, chitosan dose of 0.5 kg/t was more promising than cationic starch dose of 5 kg/t with all pulps. Paper was produced from 85% agro and 15% hardwood pulp and 0.5 kg/t of chitosan at wet-end after surface sizing with oxidized starch. It improved the tear index, Taber stiffness, double fold and air permeance by 2.7%, 6.5%, 170%, and 300%, respectively with 18.4% decrease in Cobb 60 as compared to paper made with 100% hardwood pulp. FTIR analysis was further done to evaluate the effect on crystallinity ratio and energy changes in hydrogen bonds in the papers of differently blended pulps after surface sizing. The study signifies the enhancement in strength and surface properties of paper made using agro pulp after addition of biopolymers at wet-end with and without surface sizing. Highlights • Mixing hardwood (HW) pulp with agro (AG) pulp to improve its paper properties. • Use of wet-end additives improved the strength and surface properties of paper. • Chitosan is a more efficient wet-end additive than starch. • Paper from 15% HW and 85% AG pulp after surface sizing was comparable to hardwood. • With surface sizing using chitosan agro pulp can be used to produce good quality paper. [ABSTRACT FROM AUTHOR]