Effects of cellulose nanofibrils and starch compared with polyacrylamide on fundamental properties of pulp and paper.

Bio-based additives received significant attention in pulp and paper properties improvement. For this, the most cited biochemical Cellulose Nano Fibrils (CNFs) and Cationic Starch (CS) were experimentally compared with the most declared synthetic chemical, Cationic Polyacrylamide (CPAM). SEM images showed better paper surface filling by the utilization of the chemicals. The three studied polymers, in solely or combination mechanism, improved mainly bagasse pulp and paper properties compared to the blank sample, except for pulp drainage, which decreased by CNFs to lower volumes presumably due to its intrinsic characteristics. Cationic polymers (CP) compared to CP/CNFs approaches increased pulp retention and drainage but decreased paper density and strengths. The best pulp retention and drainage achieved by CS followed by CPAM, while paper air persistency, density, and strength properties evaluated highest by CP/CNFs followed by CNFs. Generally, CS revealed a more significant improvement in pulp and paper properties than CPAM either with or without CNFs.

Facile Isolation of LCC-Fraction from Organosolv Lignin by Simple Soxhlet Extraction.

A new fractionation protocol for wheat straw organosolv lignin was developed on the basis of the dominating H-bonding orientations of its components. Acetone as H-bond accepting aprotic polar solvent and methanol as H-bond donating and accepting protic polar solvent were used in sequence. Obtained fractions were structurally and thermally analysed. The protocol allowed for the generation of purified lignin fractions and the isolation of a novel, yet unobserved lignin carbohydrate complex (LCC) fraction. This LCC fraction was found to contain exclusively phenyl glycosides and γ-esters as LCC motifs.

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.

Effects of bagasse microfibrillated cellulose and cationic polyacrylamide on key properties of bagasse paper.

This study explores the benefits of using bagasse microfibrillated cellulose (MFC) in bagasse paper. Two different types of MFC were produced from DED bleached soda bagasse pulp. The MFC was added to soda bagasse pulp furnishes in different amounts. Cationic polyacrylamide (C-PAM) was selected as retention aid. The results show that addition of MFC increased the strength of paper as expected. Interestingly, 1% MFC in combination with 0.1% C-PAM yielded similar drainage time as the reference pulp, which did not contain MFC. In addition, the samples containing 1% MFC and 0.1% C-PAM yielded (i) a significant increment of the tensile index, (ii) a minor decrease of opacity and (iii) preserved Gurley porosity. Hence, this study proves that small fractions of MFC in combination with adequate retention aids can have positive effects with respect to paper properties, which is most interesting from an industrial point of view.

The effects of fungi pre-treatment of poplar chips on the kraft fiber properties.

Poplar chips were pre-treated by Trametes versicolor for 1, 2 and 3 weeks. Pre-treated chips, after washing, have been air dried for kraft pulping to achieve pulp kappa number of about 20. Pulp samples have been analyzed by Bauer Mc Nett, Kajaani analyzer and SEM. The results indicated that fungi pre-treatment of chips can degrade lignin and carbohydrates and affect kraft pulping and fiber characteristics. Higher chemical charge in pulping, lower fine and higher long fiber fraction were observed in pre-treated pulp samples in comparison with others. Fiber length, cross sectional area, width, cell wall thickness and volume index were increased by increasing pre-treatment time while fine length, fiber coarseness and curl have been reduced. Based on the study findings, with respect to higher fiber length, lower fine, and lower fiber curl and coarseness, 2-weeks pre-treatment of chips was recommended to produce acceptable overall fiber properties in kraft pulping.