A biobased synthesized N-hydroxymethyl starch-amide for enhancing the wet and dry strength of paper products

The aim of this research was to develop a bio-based paper strength agent for the replacement of petroleum-based paper strength agents. Cationic starch was modified with 2-chloroacetamide in aqueous media. The modification reaction conditions were optimized based on the acetamide functional group incorporated into cationic starch. Further, modified cationic starch was dissolved in water and then reacted with formaldehyde to produce N-hydroxymethyl starch-amide. 1 % N-hydroxymethyl starch-amide was mixed with OCC pulp slurry before preparing the paper sheet for testing the physical properties. The wet tensile index, dry tensile index, and dry burst index of the N-hydroxymethyl starch-amide-treated paper increased 243 %, 36 %, and 38 %, respectively, compared to the control sample. In addition, comparative studies were done between N-hydroxymethyl starch-amide and commercial paper wet strength agent GPAM and PAE. The wet tensile index of 1 % N-hydroxymethyl starch-amide-treated tissue paper was similar to GPAM and PAE, and 2.5 times higher than the control sample.

Surface coating of chitosan of different degree of acetylation on non surface sized writing and printing grade paper

Chitosan is a renewable biopolymer which can be applied on the surface of writing and printing (W&P) grade paper to enhance its different properties. A variety of chitosan is available based on degree of acetylation (DA), molecular weight, viscosity, etc. DA has a profound effect on the performance of chitosan in many applications. Present study compared the performance of different DA chitosan for surface application of W&P grade paper. Chitosan samples of 23 %, 16 % and 6% DA were studied for their impact on various physical and surface properties of W&P grade paper. Surface coating of chitosan was done at 1.6 ± 0.2 g/m² (lower dose) and 2.3 ± 0.3 g/m² (higher dose) on W&P grade paper. Some properties including air permeance, TEA, showed considerable effect of DA in which high DA chitosan outperformed the low DA. Broadly, chitosan with different DA had varied impact on individual properties of paper.

Effects of cationic starch in the presence of cellulose nanofibrils on structural, optical and strength properties of paper from soda bagasse pulp

The effects of widely available bio-based additives, cellulose nanofibrils (CNFs) (0.1, 0.5, 1, and 2 wt%, based on dry weight of pulp) in combination with high degree of substitution cationic starch (CS) (0.2, 0.4, and 0.6 wt%, based on dry weight of pulp) on the structural, optical and strength properties of handsheet paper made from soda bagasse pulp were studied. Obtained results indicated that both the type and loading level of the additives had meaningful effects (99% confidence level) on the evaluated properties. Scanning electron microscope (SEM) images showed the retention and reinforcing effects of the additives on the paper network. Tensile and burst strengths increased continuously with increasing levels of the bio-additives up to 33% and 23% (0.6 CS/2% CNFs), respectively. However, the cellulose nanofibrils improved retention and drainage of the pulp at the lower levels (0.5 CS/0.1 CNFs), presumably due to complex interaction between CNFs and CS. Moreover, for the handsheet papers made of semi-bleached soda bagasse pulp, higher addition of CNFs improved the brightness of paper.