WOOD RESEARCH Volume 71, Number 1, 2026
Süleyman Kuştaş, ENGİN DERYA GEZER, and Sefa Durmaz

THE EFFECTS OF PRE-MICROWAVE TREATMENT ON IMPREGNATION PROPERTIES AND SOME MECHANICAL PROPERTİES OF SPRUCE WOOD TREATED WITH CCA

In this study, spruce wood speciemens were subjected to microwave (MW) pre-treatment prior to impregnation. The samples had an initial moisture content (MC) of 60% and were exposed to MW irridation in a microwave oven for 5, 5.5, and 6 min, while maintaining a constant power level of 800 W. Following the MW pre-treatment, the speciemens were impregnated with a 1.5% CCA solution using a vacuum-pressure method consisting if an initial vacuum phase of 20 min followed by a pressure stage of 30 min. Retention values and penetration depths were subsequently measured for each treatment group as well as for untreated control samples. The results indicated that MW pre-treatment significantly improved both retention and penetration performance. The retention values obtained for speciemens treated for 5, 5.5, and 6 min were 5.37, 6.04, and 6.18 kg/cm3, respectively, whereas the control samples exhibited a retention level of 3.64 kg/cm3. These findings demonstrate that MW pre-treatment enhances the impregnation efficiency of spruce wood. However, the treatment also led to reductions in certain mechanical properties, including modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength parallel to the grain (CS).

WOOD RESEARCH Volume 67, Number 1, 2022
Seref Kurt

Effects of liquid nitrogen in hardly impregnable fir wood

The main purpose of this study was to develop new methods to eliminate the problems encountered during the impregnation of wood material, and in this context, to improve the retention of wood material by using liquefied nitrogen. Uludağ Fir (Abies nordmanniana subsp. Bornmulleriana) was used as wood material impregnated with Tanalith-E, Immersol aqua and borax. The effects of liquid nitrogen and the amount of retention on the mechanical properties were investigated. Application of liquid nitrogen before impregnation has increased the retention in fir wood by an average of 150-200% in all impregnation methods, compared to the groups without liquid nitrogen application. Despite this increase in retention amounts, no significant changes were observed in mechanical properties due to the application of liquid nitrogen.

WOOD RESEARCH Volume 61, Number 5, 2016
Kuňa Vladimír, Balberčák Jozef, Elena Opálená, Pažitný Andrej, ALBERT RUSS, and Jiří Schwartz

The effect of multi-component retention systems on the properties of the paper suspensions

This study presents the influence of retention reagents and multi-component retention systems on properties of pulp suspension which is used during toilet paper production. The following relationships were evaluated: influence of retention systems on rate of pulp suspension water drainage, values of specific cationic and anionic demand, Zeta potential of fibers, WRV values of fibers and water turbidity. The best results were achieved from applying three-component retention system which consisted of micro-milled bentonite Hydrocol OT, modified cationic polyethylenimin Polymín SK and cationic polyacrylamide Percol 830. The above mentioned three-component retention system resulted in increased rate of pulp suspension drainage by 43 %, improvement of water turbidity by 50 % and decrease of specific cationic demand by 33 %. The proposed retention system resulted in improved values of WRV pulp suspensions, which led to decrease of values by about 10 %. Influence of three-component retention system resulted only in minimal decrease of Zeta potential values for fibers.

WOOD RESEARCH Volume 66, Number 4, 2021
Hess Dominik, Pařil Petr, Dömény Jakub, and Baar Jan

Permeability and mechanical behaviour of microwave pre-treated Norway spruce ripewood

This is a study of the influence of microwave (MW) pre-treatment on the permeability of Norway spruce ripewood (Picea abies L. Karst) as it affects its mechanical properties. Specimens were treated under variable moisture content, MW intensity, and impregnation processes. According to the results, the specimens with an initial moisture content of 45–65% exhibited the highest permeability values compared to reference samples. An insignificant difference was found between MW pre-treatments at 2 and 3 kW. Statistically significant results were found after long-time (24h) vacuum-pressure impregnation (LP). The average retention value following LP was 132 kg.m-3, which is almost three times greater than the MW-treated groups impregnated in a short-time vacuum-pressure process. The average depth of penetration after LP was 2.0 mm and the proportion of the impregnation area following LP was 17.6%. MW pre-treatment had no effect on the impregnability or the mechanical properties of the wood; other MW regimes are open for further examination.