Usability of Particles Made from Lesser-Used European Wood Species Mixed with Spruce Particles in the Particleboard Core Layer Roman Reh, Jan Izdinsky, Dominik Hrusovsky, Pavel Kral, Tomas Pipiska, Miroslav Jopek Polymers, 2025 The effects of produced wood particles from three wood species—alder, birch, and larch—added in various amounts in the particle mixture consisting of spruce particles and three tested wood species in a particleboard core layer on selected physical and mechanical properties of particleboard were studied. In a laboratory, 16 mm thick three-layer urea–formaldehyde (UF)-bonded particleboards were produced at 5.23 MPa, 240 °C, and with a 10 s/mm pressing factor. Two particleboard surface layers consisted of fine spruce particles. In the particleboard core layer, spruce particles were combined with particles from alder, birch, and larch. The tested particleboards containing alder, birch, and larch were characterized by approximately identical thickness swelling and they met the requirements of the conventional values stated by major particleboard manufacturers of 8–10%. The tested particleboard in all variations met the minimum strength value P2 particleboard in three-point bending, which is conventionally set at 11.0 MPa. The tested particleboard also exceeded the required values of modulus of elasticity in bending and internal bond strength. Analysis of the relationships demonstrated by the density profile confirmed that all three investigated wood species are usable in a mixture of core particles of high-quality particleboard in the recommended amounts (10, 15, 20%).
Advances in Wood-Based Composites Lubos Kristak, Roman Reh, Marius Catalin Barbu, Eugenia Mariana Tudor Polymers, 2025 The significance of wood-based composites has grown substantially in recent years due to their enhanced material efficiency, sustainability, and versatile applications [...]
Characterization of randomly oriented strand boards manufactured from juvenile wood of underutilized wood species Tomáš Pipíška, Marek Nociar, Pavel Král, Jozef Ráheľ, Pavlo Bekhta, Roman Réh, Ľuboš Krišťák, Miroslav Jopek, Barbora Pijáková, Rupert Wimmer, Milan Šernek European Journal of Wood and Wood Products, 2024 The wood-based panel industry in Europe, which is dominated by the use of Norway spruce, will face new challenges due to environmental changes and the bark-beetle calamity, which started a new era of forestry. To explore the possibility of replacing spruce with other wood species, juvenile wood of nine underutilized wood species (Scots pine, European larch, poplar, willow, alder, birch, European beech, English oak and hornbeam) were used to make randomly oriented strand boards (OSBs). Single-layer OSBs were produced with 3% pMDI resin and 0.5% wax. Standard physical and mechanical properties were measured. The bending strength (MOR) values showed that there was no statistically significant difference between the values for, on the one hand, spruce (34.6 MPa) and, on the other, larch (25.9 MPa), poplar (25.2 MPa), willow (27.8 MPa), alder (34.3 MPa) or birch (27.1 MPa). A similar trend was found for the boards modulus of elasticity (MOE). The highest MOE values of 5,185 MPa and 4,472 MPa were found for spruce and alder, respectively. There was no significant difference between spruce and other wood species in internal bond strength. Boards made from high-density wood species showed better physical performance, whereas those made from low-density wood species (except pine) gave better mechanical properties. Strand-generalized characteristics, such as the slenderness ratio and specific surface, were analyzed for all investigated physical and mechanical properties. European larch, poplar, willow, and alder are potential wood species for manufacturing OSBs in future without mixing species, as they can replace spruce in the wood-based panel industry.
Perspectives on Using Alder, Larch, and Birch Wood Species to Maintain the Increasing Particleboard Production Flow Roman Reh, Lubos Kristak, Pavel Kral, Tomas Pipiska, Miroslav Jopek Polymers, 2024 Particleboard, engineered wood products as part of a large family of wood composite materials, developed in use mainly in the 1950s and 1960s to utilize inferior wood and wood waste when good-quality wood was in short supply; the annual production capacity worldwide is over 100 million m3. It is also necessary to have a lot of wood raw material for its production, although raw material resources are limited on our planet. In addition to the main wood species, it is therefore possible to think about the wider use of alternative, lesser-known European species of alder, larch, and birch in particleboard production. These three wood species represent an eco-friendly and sustainable wood alternative to the conventional wood raw materials used. This review confirms the diversity of the use of these three species in different fields and proves their suitability in relation to particleboard production. Fundamental research is ongoing in certain universities to determine the proportional shares of use of these tree species in particleboard (in a certain weight proportion in their core layers) for the purpose of formulating the correct technology shares and rules for their application in the wood-based panel industry.
Determining the Dynamic Properties of Spruce Wood Using the Taylor Anvil Test Miroslav Jopek, Radek Ridky, Pavel Kral, Tomas Pipiska, Jozef Rahel, Roman Reh, Lubos Kristak Bioresources, 2024 Spruce wood is one of the most widely used materials in the production of lightweight wood-based composites in central Europe. The quality, weight, and geometric parameters of wood chips have a significant impact on the resulting quality of the manufactured composite product. Numerical simulations are necessary for advanced optimization of the quality of composite components and the manufacturing process itself. These simulations require adequate input material data and a model to produce results applicable to the output of industrial practice. In this study, a material model for spruce wood was established using the Taylor anvil test (TAT). This, in contrast to the commonly used Hopkinson compression test, corresponds better to the actual loading process. A new measurement method for shock pulses was developed to implement TAT obtained data for a realistic material model. The method was compared with numerical simulations in Ansys LS DYNA. Based on the results, parameters for the Johnson-Cook equation were determined, which can be applied in the production of disintegrations and, consequently, in the dynamic loading of spruce composite materials.
Molded Plywood with Proportions of Beech Bark in Adhesive Mixtures: Production on an Industrial Scale Roman Reh, Lubos Kristak, Jan Sedliacik, Pavlo Bekhta, Anita Wronka, Grzegorz Kowaluk Polymers, 2024 Molded plywood is used for furniture components such as seats, backrests, or integral seat shells, and it must be durable and harmless to health. Molded plywood is made with urea-formaldehyde (UF) adhesives; therefore, the issue of the fillers used in them is important. The potential of using ground beech (Fagus sylvatica L.) bark as an eco-friendly additive in UF adhesives for molded plywood manufacturing was investigated in this work. Wheat flour was used as a reference filler. The beech bark (BB) level as a filler was 10%, a value verified under laboratory conditions. Nine-layer flat and molded plywood were produced under industrial conditions from beech veneers bonded with a UF adhesive mixture. The mechanical (bending strength and bonding quality) and physical (swelling and absorbency values after 2 and 24 h) properties of the industrially fabricated molded plywood were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical properties of the molded plywood with the addition of BB in the adhesive mixture were acceptable and met these standards’ requirements. The positive effect of BB in the UF adhesive mixture on a reduction in formaldehyde emissions from the molded plywood was also confirmed. BB, considered to be wood-processing industry waste or a by-product, has significant potential to be used as a filler in UF resins for molded plywood production, providing an environmentally friendly, inexpensive solution for the industrial valorization of bark as a bio-based formaldehyde scavenger.
Investigation of Thermophysical parameters of Historical Fir Wood using Hot Disk Method under Room Ambience Rupali Tiwari, Richard Hrčka, Vlastimil Boháč, Roman Réh, Valentina Lo Giudice, Luigi Todaro, Lubos Kristak Aip Conference Proceedings, 2024 The study aims were to investigate the Thermophysical properties of fir wood (Abies alba Mill.) using the Hot Disk transient method under standard room conditions. The experiment was conducted on fir wood samples from a tree dating back to 1555 years ago examining three distinctive sample orientations: radial, tangential, and longitudinal. The motivation for working with such an ancient wood sample in addition to using a popular transient measurement device was to study the heat transfer behavior with respect to different cut orientations and the relationship between heat penetration depth and thermal diffusivity (), thermal conductivity () and volumetric heat capacity (c). The height of the thermal response curve in the tangential and radial direction showed significantly enhanced thermal response heights compared to the longitudinal direction of measurements. The Thermophysical properties were measured at room temperatures at relative air humidity of 65%. The samples volume density of 414.5 kg m-3 and 12% moisture content. The thermal conductivity values measured by the Hot Disk device were in range from 0.115 W (m K)-1 up to 0.175 W (m K)-1 . The results obtained from the Hot Disk method were also compared to the previously published quasi-stationary method by R. Hrcka, et al., (2017). The validation of the thermal response curves was confirmed by comparing the shape of the thermal responses. The study significantly contributes to the knowledge of the thermal conductivity of fir wood when measured at different cut orientations, providing invaluable insights into the complex Thermophysical characteristics of such wood material.
The Influence of the Flatness of the Particleboard Composite Samples on the Accuracy of the Measurement of Thermal Properties by Pulse Transient Method Vlastimil Boháč, Rupali Tiwari, Lubos Kristak, Roman Réh, Ján Hudec, Vladimír Štofanik, Valentina Lo Giudice, Luigi Todaro Aip Conference Proceedings, 2024 Recently, new composite materials based on natural wood-based materials have been increasingly used in modern construction of houses because of their good physical, mechanical and thermal insulation properties. This raises the need to characterize their Thermophysical properties. As part of our project 'Research of selected properties of sustainable insulating materials with the potential for use in wooden buildings', we measured samples of High and Middle density particleboards made from chips of Turkey oak wood (Turkish oak HDPB, Turkish oak MDPB) and samples made from mixture of Turkey Oak wood and Orange wood (OOPB). A cuboid model for the pulse transient method was used to estimate the parameters. The model takes into account the cuboid geometry of the sample with a square base, the heat losses from the free surface of the sample to the surroundings using the coefficient of heat transfer from the surface of the sample to the surroundings in the lateral direction, as well as the infinitely large heat capacity of the heat exchangers between which the sample is placed. The heat transfer coefficient between the heat source and the sample is infinitely large. The surface of the particleboard is usually rough and porous due to the size and nature of its particles. In addition, the interfaces of the three parts of the sample set are hand-polished, so that the edges and corners are not perfectly flush with the central area of the surface. As a result of manual polishing, the interfaces at the corners and edges of the sample parts usually have air-filled gaps. Free gaps cause additional thermal resistance to heat flow from the heat source to the body of the sample. Then, the coefficient of heat transfer from the heat source to the sample is not infinitely large and does not correspond to the conditions of the cuboid model. While the Turkey Oak HDPB had a perfectly flat surface, the Orange-Oak PB suffered from loose gaps at the interfaces. Therefore, we filled them with silicone glue as a thermal contact agent and measured them again. The consequence of flatness differences for all results was discussed within the theoretical analysis based on sensitivity coefficients, uncertainty calculations, as well as the assumption of a thermally dependent heat transfer coefficient between the heat source, air gap and the sample. The criterion for the quality of the fitting of the thermal responses by the cuboid model was the residual graph within the thermal noise of the thermocouple ± 0.005 K.
Latest advancements in high-performance bio-based wood adhesives: A critical review M. Hazwan Hussin, Nur Hanis Abd Latif, Tuan Sherwyn Hamidon, Nor Najhan Idris, Rokiah Hashim, Jimmy Nelson Appaturi, Nicolas Brosse, Isabelle Ziegler-Devin, Laurent Chrusiel, Widya Fatriasari, Firda Aulya Syamani, Apri Heri Iswanto, Lee Seng Hua, Syeed Saiful Azry Osman Al Edrus, Wei Chen Lum, Petar Antov, Viktor Savov, Muhammad Adly Rahandi Lubis, Lubos Kristak, Roman Reh, Jan Sedliačik Journal of Materials Research and Technology, 2022
Non-wood lignocellulosic composites Marius C. Barbu, Roman Reh, Ayfer Dönmez Çavdar Materials Science and Engineering Concepts Methodologies Tools and Applications, 2017
Wood-based composites Marius C. Barbu, Roman Reh, Mark Irle Materials Science and Engineering Concepts Methodologies Tools and Applications, 2017
Effect of Angle of Glued Area on Tensile Strength of Birch Plywood Jointed With Scarf Joint Acta Facultatis Xylologiae, 2011
Decay resistance of laminated veneer lumbers from European oaks Wood Research, 2010
RECENT SCHOLAR PUBLICATIONS
Substituting spruce with larch, alder and birch in strand board manufacture T Pipíška, P Bekhta, J Ráheľ, M Nociar, M Šulák, P Král, R Réh, R Igaz, ... European Journal of Wood and Wood Products 84 (3), 63 , 2026 2026
Effect of high strain rate on the mechanical properties of spruce, birch, alder and larch under different moisture conditions and its implications for disintegration process M Jopek, J Řiháček, P Kral, T Pipiska, J Rahel, R Reh, L Kristak 2025
Usability of Particles Made from Lesser-Used European Wood Species Mixed with Spruce Particles in the Particleboard Core Layer R Reh, J Izdinsky, D Hrusovsky, P Kral, T Pipiska, M Jopek Polymers 17 (10), 1291 , 2025 2025 Citations: 2
Advances in Wood-Based Composites L Kristak, R Reh, MC Barbu, EM Tudor Polymers 17 (8), 1104 , 2025 2025 Citations: 4
Characterization of randomly oriented strand boards manufactured from juvenile wood of underutilized wood species T Pipíška, M Nociar, P Král, J Ráheľ, P Bekhta, R Réh, Ľ Krišťák, M Jopek, ... European Journal of Wood and Wood Products 82 (4), 927-941 , 2024 2024 Citations: 13
Properties of particleboard made from recycled municipal waste and wood particles D Hrušovský, R Réh Acta Facultatis Xylologiae Zvolen 66 (1), 33-46 , 2024 2024 Citations: 4
Perspectives on using Alder, Larch, and Birch Wood Species to maintain the increasing particleboard production Flow R Reh, L Kristak, P Kral, T Pipiska, M Jopek Polymers 16 (11), 1532 , 2024 2024 Citations: 18
Determining the dynamic properties of spruce wood using the Taylor anvil test M Jopek, R Ridky, P Kral, T Pipiska, J Rahel, R Reh, L Kristak BioResources 19 (2), 3725 , 2024 2024 Citations: 5
Molded plywood with proportions of beech bark in adhesive mixtures: production on an industrial scale R Reh, L Kristak, J Sedliacik, P Bekhta, A Wronka, G Kowaluk Polymers 16 (7), 966 , 2024 2024 Citations: 7
Požiarne vlastnosti nových drevných kompozitov obsahujúcich odpadové plasty z automobilov I ČABALOVÁ, A DARABOŠOVÁ, M ZACHAR, J KRILEK, V MANCEL, ... Waste Forum , 2024 2024
Investigation of thermophysical parameters of historical fir wood using hot disk method under room ambience R Tiwari, R Hrčka, V Boháč, R Réh, VL Giudice, L Todaro, L Kristak AIP Conference Proceedings 3126 (1), 020020 , 2024 2024 Citations: 2
The influence of the flatness of the particleboard composite samples on the accuracy of the measurement of thermal properties by pulse transient method V Boháč, R Tiwari, L Kristak, R Réh, J Hudec, V Štofanik, VL Giudice, ... AIP Conference Proceedings 3126 (1), 020004 , 2024 2024
Fire properties of new wooden composites containing waste plastics from automobiles I ČABALOVÁ, A DARABOŠOVÁ, M ZACHAR, J KRILEK, V MANCEL, ... WASTE , 2024 2024
Evaluation of selected mechanical and physical properties of particleboards containing waste plastics V Mancel, J Krilek, I Čabalová, R Réh, M Osvaldová, A Darabošová Wood Res 69, 169-178 , 2024 2024 Citations: 3
Properties of lightweight particleboard made with sunflower stalk particles in the core layer P Bekhta, R Kozak, V Gryc, T Pipíška, J Sedliačik, R Reh, J Ráheľ, ... Industrial Crops and Products 205, 117444 , 2023 2023 Citations: 27
Investigation of thermophysical properties of Turkey oak particleboard for sustainable building envelopes R Tiwari, V Boháč, R Réh, VL Giudice, L Todaro, V Vretenár, V Štofanik, ... Developments in the Built Environment 16, 100228 , 2023 2023 Citations: 6
Latest advancements in the development of high-performance lignin-and tannin-based non-isocyanate polyurethane adhesive for wood composites AH Iswanto, MAR Lubis, J Sutiawan, SSO Al-Edrus, SH Lee, P Antov, ... Polymers 15 (19), 3864 , 2023 2023 Citations: 34
Adhesion and cohesion strength of phenol-formaldehyde resin mixed with different types and levels of catalyst for wood composites F Fitrianum, MAR Lubis, YS Hadi, RK Sari, MI Maulana, L Kristak, ... Journal of Composites Science 7 (8), 310 , 2023 2023 Citations: 23
Application of wood composites III SH Lee, P Antov, L Kristak, R Reh, MAR Lubis Applied Sciences 13 (11), 6712 , 2023 2023 Citations: 6
Advanced Eco-Friendly Wood-Based Composites II R Reh, L Kristak, MAR Lubis, SH Lee, P Antov MDPI-Multidisciplinary Digital Publishing Institute , 2023 2023
MOST CITED SCHOLAR PUBLICATIONS
Handbook of wood chemistry and wood composites RM Rowell CRC press , 2012 2012 Citations: 2826
Recent progress in ultra-low formaldehyde emitting adhesive systems and formaldehyde scavengers in wood-based panels: A review L Kristak, P Antov, P Bekhta, MAR Lubis, AH Iswanto, R Reh, J Sedliacik, ... Wood Material Science & Engineering 18 (2), 763-782 , 2023 2023 Citations: 227
Latest advancements in high-performance bio-based wood adhesives: A critical review MH Hussin, NH Abd Latif, TS Hamidon, NN Idris, R Hashim, JN Appaturi, ... Journal of Materials Research and Technology 21, 3909-3946 , 2022 2022 Citations: 217
Properties of eco-friendly particleboards bonded with lignosulfonate-urea-formaldehyde adhesives and PMDI as a crosslinker P Bekhta, G Noshchenko, R Réh, L Kristak, J Sedliačik, P Antov, R Mirski, ... Materials 14 (17), 4875 , 2021 2021 Citations: 108
Eco-friendly, high-density fiberboards bonded with urea-formaldehyde and ammonium lignosulfonate P Antov, V Savov, Ľ Krišťák, R Réh, GI Mantanis Polymers 13 (2), 220 , 2021 2021 Citations: 104
Utilization of birch bark as an eco-friendly filler in urea-formaldehyde adhesives for plywood manufacturing R Réh, Ľ Krišťák, J Sedliačik, P Bekhta, M Božiková, D Kunecová, ... Polymers 13 (4), 511 , 2021 2021 Citations: 96
Functionality of beech bark in adhesive mixtures used in plywood and its effect on the stability associated with material systems R Réh, R Igaz, Ľ Krišťák, I Ružiak, M Gajtanska, M Božíková, M Kučerka Materials 12 (8), 1298 , 2019 2019 Citations: 79
Properties of high-density fiberboard bonded with urea–formaldehyde resin and ammonium lignosulfonate as a bio-based additive P Antov, V Savov, N Trichkov, Ľ Krišťák, R Réh, AN Papadopoulos, ... Polymers 13 (16), 2775 , 2021 2021 Citations: 77
Sound-absorption coefficient of bark-based insulation panels EM Tudor, A Dettendorfer, G Kain, MC Barbu, R Réh, Ľ Krišťák Polymers 12 (5), 1012 , 2020 2020 Citations: 73
Occupational exposure to dust produced when milling thermally modified wood A Očkajová, M Kučerka, R Kminiak, Ľ Krišťák, R Igaz, R Réh International Journal of Environmental Research and Public Health 17 (5), 1478 , 2020 2020 Citations: 71
Eco-friendly fiberboard panels from recycled fibers bonded with calcium lignosulfonate P Antov, L Krišt’ák, R Reh, V Savov, AN Papadopoulos Polymers 13 (4), 639 , 2021 2021 Citations: 69
10 Wood Composites MA Irle, MC Barbu, R Réh, L Bergland, RM Rowell Handbook of Wood Chemistry and Wood Composites 321 , 2012 2012 Citations: 61
Analysis of larch-bark capacity for formaldehyde removal in wood adhesives EM Tudor, MC Barbu, A Petutschnigg, R Réh, Ľ Krišťák International journal of environmental research and public health 17 (3), 764 , 2020 2020 Citations: 60
Optimization of Parameters for the Cutting of Wood-Based Materials by a CO 2 Laser I Kubovský, Ľ Krišťák, J Suja, M Gajtanska, R Igaz, I Ružiak, R Réh Applied Sciences 10 (22), 8113 , 2020 2020 Citations: 59
Influence of urea-formaldehyde adhesive modification with beech bark on chosen properties of plywood I Ružiak, R Igaz, L Krišťák, R Réh, J Mitterpach, A Očkajová, M Kučerka BioResources 12 (2), 3250-3264 , 2017 2017 Citations: 53
Wood-based composites MC Barbu, R Reh, M Irle Research Developments in Wood Engineering and Technology, 1-45 , 2014 2014 Citations: 53
Nonwood bio-based materials L Nunes, R Réh, MC Barbu, P Walker, A Thomson, D Maskell, S Knapic, ... Performance of bio-based building materials 3, 97-186 , 2017 2017 Citations: 51
Enhanced resistance to fire of the bark-based panels bonded with clay EM Tudor, C Scheriau, MC Barbu, R Réh, Ľ Krišťák, T Schnabel Applied Sciences 10 (16), 5594 , 2020 2020 Citations: 45
Construction of wood-based lamella for increased load on seating furniture N Langová, R Réh, R Igaz, Ľ Krišťák, M Hitka, P Joščák Forests 10 (6), 525 , 2019 2019 Citations: 40
Added-value for wood bark as a coating layer for flooring tiles EM Tudor, MC Barbu, A Petutschnigg, R Réh Journal of Cleaner Production 170, 1354-1360 , 2018 2018 Citations: 39
