1. Pyrolysis oil-based polyurethane foams as a middle layer of the composite plywood sandwich panels for sustainable constructionJakub Grzybek, Jakub Michal Sandak, David Contus, Andrea Minigher, Hans Heeres, Bert van de Beld, Erfan Asgari, Rok Prislan, Anna Malgorzata Sandak, 2026, izvirni znanstveni članek Opis: The construction sector’s substantial contribution to global energy consumption and CO2 emissions motivates the development of bio-based alternatives to fossil-derived rigid polyurethane (PUR) foam cores in structural sandwich panels. This study presents a comprehensive comparison of plywood sandwich panels manufactured with a rigid PUR foam containing a fast pyrolysis bio-oil (FPBO)-derived sugar polyol diluted with triethyl phosphate and panels of identical topology produced with a commercial reference PUR foam. In the bio-based formulation, a fraction of the sorbitol-based polyether polyol was replaced with the FPBO-derived sugar polyol. Both systems were characterized at the foam and panel levels for cellular microstructure, skeletal and envelope density, thermogravimetric stability, flammability, color, thermal conductivity and heat capacity, internal bond strength, compressive properties, and normal-incidence sound absorption and transmission loss. The newly developed foam exhibited similar skeletal density and porosity to the reference, comparable thermogravimetric stability with a slightly higher char residue, and lower thermal conductivity across the tested temperature range. Mechanical properties, including compressive strength, compressive modulus, and internal bond strength, showed minor reduction but remained within a comparable range. A distinct color change was observed, attributable to the presence of chromophoric constituents of the FPBO fraction. Overall, the results indicate that partial substitution of the fossil polyol with an FPBO-derived sugar polyol is technically feasible, yielding materials with comparable thermal, mechanical, or acoustic performance. No consistent performance advantage of either system was observed across the evaluated properties. The results support the potential of pyrolysis-derived bio-polyols for use in sustainable structural insulation products.
Ključne besede: bio-based polyol, fast pyrolysis bio-oil, rigid polyurethane foams, waste valorization
Objavljeno v RUP: 14.07.2026; Ogledov: 108; Prenosov: 4
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2. Wood modification using Fast Pyrolysis Bio-Oil (FPBO) : formulation development, characterization, and evaluation of wood performanceAnna Malgorzata Sandak, Faksawat Poohphajai, Amina Selmanović, Rene Alexander Herrera Diaz, Jakub Grzybek, Kelly Peeters, Sasikala Perumal, Edit Földvári-Nagy, Lei Han, Richard Acquah, Jakub Michal Sandak, 2026, izvirni znanstveni članek Opis: This study presents a wood modification process using Fast Pyrolysis Bio-Oil (FPBO) as a fully biobased alternative to conventional, fossil-based and potentially toxic preservatives such as copper salts, organic biocides, and creosote. Standard FPBO was used in the devel- opment of 10 formulations, which were systematically characterized in terms of pot life, viscosity evolution, density, and pH. Radiata pine samples were subsequently impregnated using a bench-scale reactor, with specimens prepared in multiple geometries to assess treat- ment performance across different dimensions. The modified wood was comprehensively characterized with respect to moisture uptake, dimensional stability, density, mechanical strength, fixation efficiency, biological durability, and VOC emissions. Additional screening focused on properties relevant to outdoor applications, including aesthetic appearance and colour uniformity after UV exposure. The results enabled the identification of three top-performing formulations, treatments H, A, and E, which exhibited the most favourable balance between durability, environmental performance, and structural integrity. Overall, the findings demonstrate the strong potential of FPBO-based impregnation as a sustainable, multifunctional, and high-performance alternative for advanced wood protection systems.
Ključne besede: wood modification, fast pyrolysis bio-oil (FPBO), durability, bio-based impregnation treatment
Objavljeno v RUP: 29.06.2026; Ogledov: 197; Prenosov: 4
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3. Thermal energy storage and leakage prevention of phase change materials via one-step impregnation and in-situ polymerization process in hardwoodJakub Grzybek, Gabriel Zsembinszki, Emiliano Borri, Alina Meindl, Zuzana Paschová, Alexander Petutschnigg, Luisa F. Cabeza, Thomas Schnabel, 2026, izvirni znanstveni članek Opis: Wood is a versatile material widely used in building construction, but its low thermal mass limits its ability to regulate indoor temperatures and mitigate thermal load peaks. Phase change materials are effective at storing thermal energy, but when impregnated into wood, they leak out, compromising performance and restricting their use in buildings. This study introduces a novel one-step impregnation process combined with in-situ polymerization using furfuryl alcohol and a capric-stearic acid phase change material mixture to create a sustainable material for thermal energy storage. Various formulations were tested on European beech (Fagus sylvatica L.) to evaluate effectiveness of the approach. The results confirm that this method successfully prevents phase change material leakage. Moreover, differential scanning calorimetry and nuclear magnetic resonance verified that phase change materials retain their thermal energy storage functionality, with no chemical cross-linking between the phase change materials and furfuryl alcohol. The treated wood showed up to 185 % higher thermal energy storage capacity, enhanced dimensional stability (anti-swelling efficiency up to 87 %), and 28 % higher compressive strength than untreated wood. It is a step towards sustainable, multifunctional, leakage-free, enhanced mechanical properties, improved dimensional stability wood for thermal energy storage for building applications, with potential for further optimisation and characterisation.
Ključne besede: bio-based materials, fatty acid, furfuryl alcohol, sustainable building materials, wood modification, phase change materials
Objavljeno v RUP: 09.01.2026; Ogledov: 670; Prenosov: 10
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4. Investigating the degradation of tannin furanic foams in soil environments : experimental insightsJonas Eckardt, Paolo Carletti, Jakub Grzybek, Giancarlo Renella, Gianluca Tondi, 2025, izvirni znanstveni članek Opis: In the search for bio-based alternatives to petroleum-based materials, extensive research has been carried out on tannin- based foams over the last decades, demonstrating their potential use as insulation materials for buildings. These foams have been studied in depth for their chemical and physical properties and were already considered for upscaling. However, concerns remain about the end of their life cycle. While tannin foams can be partially recycled in new tannin foams, reused as ammonia scavenger, or thermally valorised, their impact on soil upon disposal or when potentially used as ammonia mitigators in agriculture remains unclear. This study investigated the degradation dynamics and potential effects of tan- nin furanic polymer on soil health. A decrease in the mass of the tannin foam particles by about 10% within 24 weeks indicated microbial degradation, which was further enhanced by the occurrence of leachable fractions throughout the experiment. Chemically, this degradation was associated with a reduction in carbohydrates and/or furanics, leading to a relative increase in aromatic components, paralleled by increased β-glucosidase activity. Phenol oxidase and arylesterase activities fluctuated depending on time and soil type, suggesting their roles in different stages of phenolic degradation, while catechol oxidase activity either decreased or remained unchanged. Enzymatic activities for FDA and β-glucosidase, indicators of soil health and microbial activity, tendentially increased in the presence of tannin foam, showing that the tested foam had no negative effect on general soil microbial activity.
Ključne besede: tannin furanic foam, soil FDA hydrolase activity, soil β-glucosidase activity, ATR FT-IR
Objavljeno v RUP: 02.12.2025; Ogledov: 735; Prenosov: 5
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