WOOD RESEARCH Volume 70, Number 4, 2025
ANDREJ PAŽITNÝ, JURAJ KRIŠTA, and MARTA PÁTEKOVÁ

IMPROVING SHEET MATERIAL PROPERTIES IN PAPERMAKING FROM SECONDARY FIBER AND CORN KERNEL’S CASING

The paper is focused on monitoring the impact of corn kernel’s casing content added to old corrugated containers on density, brightness, ultimate tensile load, tensile index, tensile energy absorption, breaking length, tensile strength, relative elongation, air resistance of paper sheet according to Gurley and zero-span tensile strength. A content of 40 % and 60 % corn kernel’s casing added to secondary fiber based on old corrugated containers was tested. Suspensionsprepared by acidification and beating were subjected to chelation and three-stage bleaching.The bleaching method consisting of three steps was applied in two series – acidified and beaten pulp suspension with Schopper-Riegler (°SR) beating degree at level of 72 °SR.The first bleaching step includedperoxide bleaching with added sodium hydroxide, chlorine dioxide bleaching and peroxide bleaching in an alkaline environment. The effect of chemical and hydro-mechanical treatment on the resulting physical and mechanical characteristics of prepared paper sheets was investigated.

WOOD RESEARCH Volume 69, Number 4, 2024
MONIKA STANKOVSKÁ, JURAJ KRIŠTA, ŠTEFAN BOHÁČEK, ALBERT RUSS, and ANDREJ PAŽITNÝ

COMPARISON OF TWO METHOD FOR ISOLATION OF FIBRILLATED CELLULOSE FROM LIGNOCELLULOSIC BIOMASS

Fibrillated cellulose from distillery refuse based on maize starch was prepared by two different procedures. The effect of sonification was evaluated atacid-alkali extractionas well as the type of used acid. The results from the alkali-acid procedure were compared with these obtained by method of steam explosion at different temperatures. The acid-alkali method brings a better result regarding degradation of hemicellulose and lignin as well as cellulose. Lignin/hemicellulose were only released from lignocellulose network using steam explosion at 120-180°C. At higher temperature, the results were comparable with those obtained by acid-alkali method. Similarly pore size distribution of filter paper decreased more significantly when fibrillated cellulose from acid-alkali treatment was applied. After steam explosion, higher extend of longer still fibres remains

WOOD RESEARCH Volume 69, Number 4, 2024
ALBERT RUSS, ANDREJ PAŽITNÝ, JURAJ KRIŠTA, EMMA WESZELOVSZKÁ, and VLADIMÍR IHNÁT

ENZYMATIC HYDROLYSIS OF STEAM EXPLODED STRAW WITH THE ADDITION OF ACETIC ACID

The effect of steam explosion on the enzymatic hydrolysis of straw was investigated in the presence of 5, 10, 15 and 20% wt. addition of acetic acid. Analysis was performed at temperatures of 160, 170, 180, 190, 200 and 210°C. The concentration of monosaccharides obtained after enzymatic hydrolysis was considered the main indicator of the increased availability of cellulose due to their release into the solution. The results indicate that the addition of acetic acid increases the concentration of monosaccharides, but only at lower temperatures. The temperature of 180°C corresponded to the most effective pretreatment by steam explosion in the presence of acetic acid with the highest concentration of 10%, which corresponds to the conversion of polysaccharides to monosaccharides of 74.78%. At high temperatures above 200°C, the addition of acetic acid results in a decrease in the concentration of monosaccharides due to the high severity factor in the range of 3.94 – 4.24

WOOD RESEARCH Volume 69, Number 2, 2024
VLADIMÍR IHNÁT, HENRICH LÜBKE, ALBERT RUSS, JOZEF BALBERČÁK, VLADIMÍR KUŇA, ANDREJ PAŽITNÝ, and ŠTEFAN BOHÁČEK

LIGNOCELLULOSIC LINERS BASED ON WOOD WOOL

Basic physical and mechanical properties of lignocellulosic liners up to 1.5 mm thick with a compact and non-crumbling surface based on wood wool and thermoplastic water based glues were determined. PVAc and starch glue with a high proportion of water content were used. The dry mat was pressed gradually under high pressure up to 28 MPa and a temperature of around 190°C with the release of steam. Tests according to the CEPI (Confederation of European Paper Industries) standards were adopted. Procedures for tensile strength according to ISO 1924-2 (2008), Burst strength according to ISO 2758 (2014), puncture according to ASTM D781-68 (1973), water absorption according to ISO 5637 (1989) and porosity according to TAPPI Test method T460 were applied

WOOD RESEARCH Volume 69, Number 1, 2024
VLADIMÍR IHNÁT, HENRICH LÜBKE, RASTISLAV ČEREŠŇA, JOZEF BALBERČÁK, VLADIMÍR KUŇA, ANDREJ PAŽITNÝ, and ŠTEFAN BOHÁČEK

THIN LIGNOCELLULOSIC LINERS BASED OF SPRUCE SHAVINGS

The article is devoted to determining the basic physical and mechanical properties of sheet materials up to 1.5 mm thick based on wood shavings and PVAc glue with a high proportion of water, pressed under high pressure up to 25 MPa and a temperature of around 190°C, so that the softening of lignin caused by the generated steam, allow to create a compact and non-crumbling surface. In order to characterize the physical-mechanical properties of the new wood-based sheet material with minimum thickness and characteristic elasticity, tests according to the CEPI (Confederation of European Paper Industries) standards were adopted. Procedures for tensile strength according to ISO 1924-2 (2008), Burst strength according to ISO 2758 (2014), puncture according to ASTM D781-68 (1973), water absorption according to ISO 5637 (1989) and porosity according to TAPPI Test method T460 were applied