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This study examined the use of Plantago psyllium seed husk flour as paper additive with the aim of improving the properties of cellulose sheet. The husk flour was added in 5 wt%, 10 wt%, 20 wt% and 30 wt% to the cellulose suspensions and its effect on the handsheet properties was studied. The results showed that the direct addition of husk flour highly improves the mechanical properties of the handsheets like tensile index (with up to 400 %), burst index (with up to 600 %) and tear index (with up to 1200 %). Cobb and contact angle tests with distilled water showed that the handsheets containing husk flour are more hydrophobic compared to the unmodified handsheets. The Cobb-Unger and contact angle tests with oil revealed that the additive reduces the oil absorbency of the handsheets as well, at the highest by 86 %. Additionally, the water vapor and especially the air barrier properties were improved. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant capacity test showed that the modified handsheets had free radical scavenging properties. The direct addition of Plantago psyllium seed husk flour can be a promising, easy and green method to improve the mechanical and barrier properties, oil and water resistance of cellulose sheets. [ABSTRACT FROM AUTHOR]

Variations in wood properties such as basic density, tissue proportion, fibre dimensions and their derived indices, cellulose and lignin content of Melia dubia at five age gradations were examined to evaluate the suitability of the species for pulp and paper production. The study showed that basic density, fibre proportion, fibre length, cell wall thickness, slenderness ratio, solids factor, cellulose and lignin content increased with tree age. However, vessel proportion, fibre width and lumen width decreased. Most of the wood properties were found suitable for making good quality pulp and paper at the age of 4 and 5 years in comparison to other hardwood species among five age gradation. Hence, harvesting at fourth and fifth year of age is suggested in M. dubia for high pulp yield and better paper quality. [ABSTRACT FROM AUTHOR]

Abstract: A novel silicone release liner was prepared from porous base paper with a simple biogenic polymeric pre-coat. The introduced method does not require the typical complex pretreatment processes for a paper sheet, such as calendering or pre-coating with clay. Biogenic polymers, hydroxyethyl cellulose and methylcellulose, were used to close the pores of the paper sheet. In addition, we used polyvinyl alcohol (PVA), a commonly used barrier coating with known film-forming capabilities, as a reference to close the pores and prevent silicone penetration into the base paper. In particular, hydroxyethyl cellulose showed promising barrier properties similar to those of PVA coatings. Methyl cellulose is less appropriate for release liner production due to poor film stability and insufficient adhesion to the underlying base paper. Barrier-coatings should be applied by a blade coater rather than a roller coater to obtain homogenous coatings. When a thin silicone layer was applied to the barrier-coated papers, the measured release forces were significantly reduced from 6.5 N/25 mm, for siliconized papers without any pre-coat, to less than 1 N/25 mm after pre-coating, particularly with hydroxyethyl cellulose.Graphical abstract: [ABSTRACT FROM AUTHOR]

Abstract: The objective of the presented research was to determine the influence of cellulose coating, obtained from the cellulose solution in N-Methylmorpholine N-oxide (NMMO), on the structural and mechanical properties of paper. The effect of heating time of paper samples coated with cellulose dissolved in NMMO was also investigated. Depending on the heating time of the coating, a continuous or porous layer was obtained. Coating without any heating stage yielded a continuous cellulose layer of hydrophobic properties (higher contact angle in comparison to base paper), and paper of higher smoothness and increased tear resistance. Analysis of the paper samples showed that cellulose coating not only changed the surface properties of paper, but also significantly improved paper strength properties, such as the tensile index, elongation, bursting strength index and double folds number. Despite the process’ limitations (e.g. necessity of removing the NMMO), this method can be considered as a novel approach for paper property modification.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Highlights: [•] Laser cleaning of mechanical ground wood cellulose paper was compared with that of bleached softwood cellulose paper. [•] One order of magnitude of fluence range is available for cleaning without paper damage. [•] Above the destruction threshold, dehydration/dehydrogenation reactions and changes of the cellulose chain arrangement occur. [•] Contaminant particles are detached thermo-mechanically, by lateral blasting, by evaporation, or combustion. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the influence of acetylation on properties of paper made using the chemi-mechanical pulp (CMP) process. Industrial unbleached CMP pulp was provided (before and after refining), and paper handsheets were made. After drying, the specimens were acetylated on a heated cylinder at 120 °C, with acetic anhydride without catalyst. Physical and mechanical properties including water absorption, porosity, printability, brightness, D-folding, breaking length, tear resistance, and burst strength of samples were measured and compared between treated samples and the controls. The results showed that acetylation intensity was increased by increasing reaction time. Water absorption exhibited a significant reduction due to acetylation. Brightness, D-folding, and burst showed an increasing trend as a function of the degree of acetylation. Tear resistance was decreased by acetylation. The refining process improved acetylation and decreased porosity. The results indicated that most of the important factors were significantly influenced and improved by both acetylation and the refining process. [ABSTRACT FROM AUTHOR]

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Abstract: The influence of temperature (150–170°C), pulping time (15–45min) and soda concentration (5–10%) in the pulping of abaca on the yield, kappa, viscosity, breaking length, stretch and tear index of pulp and paper sheets, was studied. Using a factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the pulping process were derived that reproduced the former with errors lower than 25%. Using a high temperature, and a medium time and soda concentration, led to pulp that was difficult to bleach (kappa 28.34) but provided acceptable strength-related properties (breaking length 4728m; stretch 4.76%; tear index 18.25mNm2/g), with good yield (77.33%) and potential savings on capital equipment costs. Obtaining pulp amenable to bleaching would entail using more drastic conditions than those employed in this work. [Copyright &y& Elsevier]

The microscopic changes in the structure of paper at different equilibrium moisture contents were examined using the novel technique of contrast variation small angle neutron scattering (SANS). Contrast variation, by appropriate selection of the H[2]O:D[2]O ratio, was used to simplify the scattering from hydrated paper to a twophase approximation. The two phases were paper polymers (cellulose, lignin and hemicelluloses) and a phase consisting of water and voids. The twophase approximation is justified by consideration of the chemistry and density of each of the polymer species belonging to paper, and by matching the scattering length density of the sorbed moisture to air. The neutron intensity at the higher scattering angles examined was successfully fitted using the Porod law, which is applicable to scattering from a twophase system at the high scattering angle limit. This limit is related to the specific surface area between the two phases. The limiting scattered intensity of neutrons was found to increase with increasing moisture content for a range of paper materials. It is concluded that the sorption of water increased the limiting intensity because water disrupted polymerpolymer bonding. The Porod law also predicts the slope of the intensity/scattering angle curve at the high scattering angle limit. [ABSTRACT FROM AUTHOR]