Lower Equilibrium Moisture Content Research Articles

PRODUCTION OF TORREFIED BIOMASS PELLETS FROM WOODY AND AGRICULTURAL RESIDUES (TIChE2021)

Two different combined process sequences of biomass pretreatment between pelletization after torrefaction (PAT) and pelletization before torrefaction (PBT) were comparatively investigated to produce torrefied biomass pellets (TBP) from woody biomasses, e.g. Leucaena (LC) and rubberwood (RW), and agricultural residues, e.g. rice straw (RS) and sugarcane leaves (SCL). In this study, each sample was thermally treated at 260-300°C for 5 min during torrefaction process. It was found that both woody biomasses and agricultural residues had mass yield lower than 63wt%, while the bulk density of TBPs were improved higher than 400kg/m3. For equilibrium moisture content (EMC) analysis, TBPs via PBT method had lower EMC than raw pellet after being kept at 30°C for 12 days. For the thermochemical properties, the TBPs had higher FC, %C, and HHVs than raw pellets in all biomasses and increased with torrefaction temperature. When comparing the TBPs between PAT and PBT torrefied pellets, the HHVs of PBT torrefied pellets at 300°C were achieved highest at 27 MJ/kg for SCL sample, leading to lower H/C and O/C ratio closely to that of lignite. In addition, the combustion performance index (Sn) of PAT and PBT torrefied pellets was lower than raw pellets, showing a similar property as coal and lignite. Briefly, this study suggests using PBT pretreatment process to produce high quality solid fuel, particularly for agricultural residues such as SCL for a potential substitute of currently used coal.

Effect of storage on the quality of peanut grain oil

Peanut (Arachis hypogaea L.) is a grain rich in lipids and highly susceptible to oxidative damage during storage. This study evaluated the effects of storing peanut grains at different temperatures, with and without shells, on oil quality parameters. Grains with a moisture content of 8 % were stored at temperatures of 18 and 25 ± 1 °C. The evaluations were performed at the beginning of storage, at 60, 120, and 180 days. The study demonstrated that in chemical analyses, peanut grains stored in the shell maintain conceivable lipid acidity levels, even with an increase over storage time. Beta carotene and tocopherols decreased during storage. Most treatments showed increased primary (K232) and secondary (K270) oxidation products. During storage, the fatty acid profile changed at high saturation values (linoleic to oleic). Therefore, it is suggested to store peanut grains for up to 180 days, with shells, in places that favor low equilibrium moisture content and temperature to maintain the grains and oil's physical and chemical qualities.

Comparative Analysis of Fire and Explosion Properties of Lycopodium Powder

Lycopodium (L.) clavatum powder, due to its uniform particle size distribution and low equilibrium moisture content, is often used as a reference material and a calibration benchmark for dust combustion and dust explosion studies. The aim of the study was to determine its fire and explosion parameters, compare them to values obtained in the previous literature findings, and assess the appropriateness of using lycopodium powder as a reference material. The research included the determination of minimum ignition temperatures of dust layer and dust clouds, spontaneous ignition behavior, and explosion characteristics of dust clouds including maximum explosion pressure, maximum rate of explosion pressure rise, and the lower explosion limit of the air/dust mixture. The results reveal that the maximum equipment temperature used with lycopodium dust should not exceed 215 °C for dust thickness up to 5 mm. In order to eliminate the risk of lycopodium dust ignition, the temperature of the equipment surfaces that can come into contact with the dust cloud should not exceed 300 °C. In order to prevent explosions, the concentration of lycopodium dust in air should not be greater than 15 g/m3. Based on the obtained results, it can be seen that lycopodium fire and explosion parameters vary slightly, and its usage as a benchmark is considered legitimate.

Water-vapour sorption of welded bond-line of European beech and Scots pine

Abstract The wood–water interactions of welded bond-lines of European beech (Fagus sylvatica L.) and Scots pine (Pinus sylvestris L.) were in this paper studied for the first time with dynamic vapour sorption equipment. The aim of this study was to characterize the water sorption in the welded bond-line and to define to which extent it deviates from water sorption of the unwelded wood. The objective was to provide deepened knowledge about water sorption of the welded bond-line, which could be used to improve the moisture resistance of welded wood in the future. The welded wood generally had lower equilibrium moisture contents than the unwelded wood. The welded bond-lines of beech and pine showed greater hysteresis than the unwelded wood from 0 to 55 % relative humidity. All specimens showed faster adsorption than desorption. However, the welded wood showed slower adsorption but faster desorption than unwelded wood. The time to complete half of the fractional change in moisture content (E(t) = 0.5) increased as the moisture content increased. The adsorption diffusion coefficients of beech and welded beech were higher than those of pine and welded pine up to 50 % and 40 % RH, respectively. In desorption, pine had a higher diffusion coefficient than beech in the whole range of 85–0 % RH. Analogously, welded pine had a higher diffusion coefficient than welded beech in the range of 85–5 % RH. In contrast to the desorption, the welded wood always had lower adsorption diffusion coefficients than the corresponding unwelded wood. The diffusion coefficients showed irregular patterns in some ranges of the RH. Therefore, it was hard to make a clear conclusion about the water-sorption behaviour of the specimens based on the defined diffusion coefficients.

Properties of poly (vinyl alcohol) films with embedded zeolitic imidazolate framework (ZIF-8) nanoparticles for food packaging applications.

This study evaluated the physical, mechanical, barrier properties, and transition temperatures of poly (vinyl alcohol) (PVA) films with embedded zeolitic imidazolate framework-8 (ZIF-8) nanoparticles carrying a natural antimicrobial, trans-cinnamaldehyde (TC). The ZIF-8 nanoparticles were synthesized using a sonochemical method and incorporated into polymeric matrices at mass ratio concentrations of 0% (control film) to 5% weight of ZIF-8@TC to PVA. Solutions were mixed, cast onto Petri dishes and dried for 12h at 37°C in a ventilated oven. The film samples were stored in airtight containers at room temperature and used within 1 week. The engineering properties of the PVA/ZIF-8@TC films were compared with those of low-density polyethylene (LDPE) film commonly used for packaging of spinach leaves. The glass transition, melting, and crystallization temperatures of PVA compositive films all increased (p<0.05) with ZIF-8@TC concentration. When exposed to high relative humidity environments, the PVA/ZIF-8@TC films had lower equilibrium moisture content (p<0.05) than the LDPE film. Although the composite films have different tensile properties from the LDPE film, embedding ZIF-8@TC into PVA films improved the tensile strength by 17%, making the PVA/ZIF-8@TC films suitable for low load-bearing applications such as food packaging. The gas barrier properties of PVA-based films differed only slightly with added ZIF-8@TC (p<0.05). PRACTICAL APPLICATION: PVA/ZIF-8@TC films are appropriate environment-friendly alternatives to polymeric food packaging in terms of their functional properties.

Reversible and irreversible effects of mild thermal treatment on the properties of wood used for making musical instruments: comparing mulberry to spruce

Thermal treatments can be considered as an accelerated ageing, bringing partly similar changes in properties as naturally aged wood. Thermal treatment was applied on white mulberry (Morus alba L.), a dominant species for making musical instruments from middle-East to Far-East, to investigate the effects on the vibro-mechanical and physical properties of this wood, and the results compared to previously published data on spruce (Picea abies Karst.) as a reference for the soundboard of Western string instruments. Thermal treatment (TT) at 150 °C and 0% of relative humidity was applied to five analogous groups of specimens with five different durations (2.5, 8, 24, 72, 261 hours). Humidity re-conditioning of specimens was done to explore the reversibility of TT effects. Physical and vibrational properties such as specific gravity (γ), equilibrium moisture content (EMC), CIELab colorimetric values, specific modulus of elasticity (E’/γ) and damping coefficient (tanδ) in longitudinal (L) and radial (R) directions, have been measured after stabilisation of samples in standard conditions (20 °C, 65% RH), before and after TT and then after re-conditioning. Untreated mulberry had a low EMC, very low L/R anisotropy and low E’L/γ, and relatively low tanδ. Weight loss (WL) and CIELab values evolved similarly during TT for mulberry and for previous results on spruce, however, their EMC and vibrational properties were affected differently. This could be explained in part by the low anisotropy of mulberry, and in part by its particular extractives. The parts of irreversible effects, linked to chemical modification or degradation, and of reversible effects, linked to physical configuration, were different between mulberry and spruce. The applied treatments did not bring permanent “improvements” in vibrational properties of mulberry, yet its colour appearance was enhanced.

Thermodynamic analysis and modeling of water vapor adsorption isotherms of roasted specialty coffee (Coffee arabica L. cv. Colombia)

The experimental assessment and computer modeling of the water vapor adsorption isotherms of roasted specialty coffee is addressed in this study. Thus, both coffee beans and ground coffee of medium (850 μm) and fine (600 μm) particle sizes were analyzed over a range of water activities of between 0.1 and 0.9 and at temperatures of 25, 35, and 45 °C. The adsorption isotherms were determined using the dynamic dew point (DDI) method. The computer modeling of adsorption isotherms was addressed in order to describe the influence of the water activity and temperature on the equilibrium moisture content. Furthermore, the hygroscopic capacity of roasted coffee was analyzed by differential thermodynamic analysis. Experimental results and modeling showed that the high level of moisture adsorption found in the ground coffee was related to a large adsorption area, suggesting that specialty coffee should preferably be stored as beans. The Peleg empirical model was the most suitable at representing both type III upward concave adsorption behavior and the effect of temperature on the adsorption isotherms. Differential thermodynamic analysis revealed an increase in the water adsorption energy at low equilibrium moisture content, while negative Gibbs free energy values revealed the spontaneity of the adsorption process.

Effect of Environmental Humidity on the Acoustic Vibration Characteristics of Bamboo

Bamboo musical instruments, such as bamboo flute and Ching-hu (Beijing opera fiddle), can generate a crisp and melodious sound closely related to the delicate multiscale pore structure of bamboo. Bamboo is a natural hydrophilic material, and its acoustic vibration characteristics are highly sensitive to changeable environmental humidity levels. Herein, we investigated the acoustic vibration characteristics of bamboo under three conditions: constant relative humidity (status I), changeable relative humidity (status II), and subjected to water extraction (status III). Three typical parameters were selected as evaluation indicators of bamboo acoustic vibration characteristics, namely, specific dynamic elastic modulus (E′/ρ), loss tangent (tanδ), and acoustical converting efficiency (ACE). The outer bamboos (OB) had higher E′/ρ and ACE but lower equilibrium moisture content (EMC) and tanδ than the inner bamboos (IB). Under status I, bamboo showed the maximum E′/ρ and ACE and the minimum tanδ at 35% RH (relative humidity) and about 6% MC. Compared with the bamboo under status II, the bamboo under status I retained higher E′/ρ and ACE and lower tanδ. However, the bamboo under status (III) reached the maximum E′/ρ and ACE and the minimum tanδ. The bamboo musical instrument is made of bamboo with proper removal of water-soluble extractives and high fiber volume fraction and stored in a stable relative humidity environment of 35%, which has suitable acoustic vibration characteristics.

Effect of chemical composition and cell structure on water vapor sorption behavior of parenchyma cells and fiber cells in moso bamboo (Phyllostachys edulis)

Efficient water sorption in bamboo and water transport between cells are closely related to the rapid growth of bamboo and subsequent dry processing. In this study, the water vapor adsorption behavior of parenchyma cells (PCs) and fiber cells (FCs) in moso bamboo (Phyllostachys edulis) was evaluated using a dynamic water vapor sorption (DVS) test. The effects of the chemical composition and cell structure on the adsorption mechanism were investigated with the Hailwood-Horrobin (H-H) model. The effect of heat treatment on the hygroscopicity of the PCs and FCs was determined using Fourier transform infrared (FT-IR) spectroscopy, Raman mapping, and X-ray diffraction. The results showed that the equilibrium moisture content (EMC) of the PCs was higher than that of the FCs, and the contribution ratio of the PCs and FCs to the hygroscopicity (EMC at 95% RH) of the bamboo was 12:9. The hygroscopic mechanism of the PCs was obtained from the H-H model. A high hemicellulose content provided adsorption sites (-OH) in the PCs, resulting in a high multilayer water content and EMC. The PCs structure further increased the EMC through capillary condensation due to the low cell wall density, large specific surface area, and large cell cavity size. The high EMC in the outer PCs and the low EMC in the inner FCs of the bamboo slivers formed a water pressure gradient, enhancing the trans-wall diffusion of bound water coupled with pit channels in the cell wall. The heat treatment resulted in a larger reduction in the hygroscopicity of the PCs than the FCs due to the higher degradation of CO and -OH of hemicellulose and lignin and the higher cellulose crystallinity of the PCs. The PCs possessed lower thermal stability than the FCs. This research improves our understanding of the structure-composition-function relationship between the cell structure, chemical composition, and moisture adsorption of bamboo. It also provides scientific support for developing new fiber-based composite materials and the pretreatment of high value-added PC products.

Embedment properties of thermally modified spruce timber with dowel-type fasteners

This study investigates the effect of thermal modification, ThermoWood Thermo-D treatment versus no treatment, on the embedment properties of Norway spruce timber (Picea abies [L.] Karst.) with dowel-type fasteners. The test specimens were reinforced to prevent splitting of the wood. The influence of density, load direction, test specimen configuration (full hole versus half hole), moisture content, gauge points and calculation method were also evaluated. Thermal modification primarily affected the embedment strength parallel to the grain, which was ∼ 25% higher after thermal modification, mainly due to the change in physical properties because of the treatment, i.e. the lower equilibrium moisture content. The influence of the investigated parameters on embedment properties of thermally modified spruce followed similar trends as for unmodified spruce. It was for example seen that the density–embedment strength relationships still hold after the treatment despite the decrease in density and the increase in embedment strength parallel to the grain. However, after thermal modification, the influence of load direction on embedment strength was ∼30% larger and the influence of calculation method (yield versus ultimate strength) on embedment strength perpendicular to the grain was ∼10% smaller.

Chitosan‐nanocomposites as a food active packaging: Effect of addition of tocopherol and modified montmorillonite

AbstractThe development of natural biodegradable polymers to partially or totally replace synthetic polymers may be advantageous in food packaging, mainly when are associated with additional features such as active packaging. This article aimed to evaluate the effect of tocopherol concentration (0, 5, 10, and 20%) and modified montmorillonite clay (MMT15A) nanoparticles (0 and 1%) on the properties of chitosan (CS) films. The addition of tocopherol provided antioxidant activity and improved the thermal stability of the films, and acted as a plasticizer, decreasing the tensile strength, elastic modulus, and glass transition temperature of the films. Although MMT15A and tocopherol did not change the water vapor permeability, an improvement of the mechanical strength and lower equilibrium moisture content was observed when compared to the treatment made with CS alone. Both MMT15A and tocopherol allowed the production of bio‐nanocomposites with thermal, morphological, mechanical, and water‐resistant properties to be used as an antioxidant in packaging materials.Practical ApplicationsThe films containing both montmorillonite (MMT15A) and tocopherol presented an improved mechanical strength, thermal stability, and antioxidant activity when compared to the films containing the only tocopherol. Therefore, it was possible to develop antioxidant chitosan films with improved properties using up to 20% tocopherol and MMT15A. At this tocopherol and MMT 15A concentrations, the films may also be used to nutritionally enrich food, adding value to the package and the conditioned product. Furthermore, the films can also be considered edible films with combined properties.

Viscoelastic properties of thermo-hydro-mechanically treated beech (Fagus sylvatica L.) determined using dynamic mechanical analysis

Thermo-hydro-mechanical (THM) processing can improve the intrinsic properties of wood, produce new materials, and give desired form and function to new applications. THM treatments change the mechanical properties of wood and may change its viscoelastic properties as well. Therefore, the objective of this study was to assess the viscoelastic properties of THM-treated wood at several humidity and load levels. To explore these changes, this study applied a THM treatment to beech (Fagus sylvatica L.) wood with steam (620 kPa) and heat (170 °C), followed by densification and increased temperature (200 °C) in a hot-press, which was then cooled while under pressure. Two initial specimen thicknesses before THM treatment were used to study the difference between density ratios. Specimens were tested in a humidity-controlled dynamic mechanical analyser (DMA) to apply creep stress with different loading levels (20% and 30% of expected modulus of rupture) and relative humidity levels (30%, 50%, and 65% RH). The creep compliance/recovery response was monitored, and dynamic moduli were measured before and after the application of creep stress. The loss modulus measured was highest for specimens tested at 65% RH and lowest in specimens tested at 30% RH, which is a direct result of the viscous response of the material. Increased damping of the specimens was also observed at higher RH, which is typical for wood products due to added moisture in the cell wall acting as a plasticizer to cell wall polymers. Like previous studies, THM treatment lowered the equilibrium moisture content (EMC) of densified wood specimens, which affected their mechanical performance. THM treatment yields higher strength and lower EMC, suggesting that this product could be suitable for structural applications where their service life is in an indoor environment. THM treatment also resulted in decreased creep compliance and recovery compliance as compared to control specimens.

Moisture re-adsorption characteristics of hydrochar generated from the Co-hydrothermal carbonization of PVC and alkali coal

Our previous work reported to simultaneously remove the alkali and alkaline earth metals, and chlorine by co-hydrothermal carbonization (co-HTC) of high-alkali coal and polyvinyl chloride (PVC) (Fuel Process Technol, 199(2020)106277). This work is to investigate on the moisture re-adsorption characteristics of those hydrochar obtained at various co-HTC operating conditions. The results show that the water re-adsorption capacity of hydrochar was decreased with the circumstance temperature rising from 20 °C to 35 °C, while it was increased with the air humidity increasing from 50% to 80%. During the co-HTC, the addition of PVC could effectively inhibit the moisture re-adsorption behavior of hydrochar resulting from the adhere of the hydrophobic PVC to the surface of hydrochar as evidenced by SEM. The circumstance temperature had a significant influence on the effective diffusivity D over the humidity. The equilibrium moisture content (EMC) and effective diffusivity (D) could be linearly correlated with surface area and most probable pore size, respectively. The EMC of hydrochar was reduced about 0.6 mg/g as the BET surface area decreased 1 m2. The reduction of oxygen-containing groups could reduce the adsorption equilibrium time and adsorption heat. Besides, the higher circumstance humidity would cause hydrochar to release higher adsorption heat. As the humidity was increased from 70% to 80%, the heat released by 1 g hydrochar was increased about 13.82–19.63 kJ/mol. Due to the lower EMC and adsorption heat, 300 °C was supposed to be a suitable temperature for the co-HTC to obtain hydrophobic hydrochar.

Effect of storage conditions on physicochemical and microstructural properties of skim and whole milk powders

This study examined the effects of storage conditions on physicochemical and microstructural characteristics of whole milk powder (WMP) and low-, medium- and high-heat skim milk powder (SMP). Powders were stored at three temperatures (25 °C, 35 °C and 45 °C) and three humidity levels (11%, 44% and 85%) for 21 days. WMP exhibited lower equilibrium moisture content (EMC) than SMP at these storage conditions. SMP and WMP stored at 45 °C had lower EMC and monolayer moisture content than those stored at 25 °C and 35 °C. WMP had lower Tg, crystallinity and caking strength than SMP. At 85% RH, the particles became irregularly shaped, caused by lactose crystallization. Crystallization of lactose and caking of powders became prominent when Tg decreased below the storage temperature. Crystallization of lactose in these powders increased caking strength, Maillard reaction and surface free fat, particularly at high RH (85%) and high temperature (45 °C) conditions.

Effect of Water Repellents on Hygroscopicity and Dimensional Stability of Densified Fir and Aspen Woods

This study investigated the effect of pre-impregnation with water-repellent agents on the hygroscopicity and dimensional stability of fir (Abies bornmulleriana Mattf.) and aspen (Populus tremula L.) woods. After pre-vacuum treatment, the samples were impregnated at atmospheric pressure with paraffin, linseed oil and styrene, and then densified at compression rates of 20 % and 40 % at 120, 150 and 180 °C. The results showed that water repellents significantly affected the hygroscopicity and dimensional stability of the densified wood samples. Compression recovery rate (CRR), thickness swelling (TS), equilibrium moisture content (EMC), and water absorption (WA) values of the densified samples decreased with impregnation pretreatments. The linseed oil treatment gave more positive CRR and TS results than paraffin. Lower EMC and WA values were found in the paraffin-treated samples. However, the most successful results for all tested properties were determined in the styrene pretreated samples in which hygroscopicity decreased and dimensional stability increased (especially for aspen) due to increases in the compression rate and temperature related to densification conditions. In the styrene pretreated samples, the high temperature (180 °C) and compression rate (40 %) significantly reduced CRR, TS, EMC and WA, total dimensional stability was nearly achieved and the water repellent effectiveness was close to 100 %.

Sorption Isotherm of Corn Chips Made from Blends of Corn Flour and Bambara Groundnut Nut Flour

The adsorption equilibrium moisture contents of corn chips (kokoro) made from blends of maize flour and Bambara nut flour was investigated by measuring water activities at 27°C, 37°C and 40°C using the static gravimetric method. Sorption isotherms followed a type II shape in water activities range from 0.10 - 0.80 showing characteristics of most biological tissues. Five isotherm model equations were used which are BET, GAB, Oswin, Halsey and Henderson. The experiments were performed using polythene packaging and exposed petri dishes. The samples were weighed at two days interval until equilibrium was attained when three identical measurements were obtained. The equilibrium moisture content (EMC) decreased with increase in temperature at constant water activity and polythene packaging had lower EMC compared to petri-dishes. Oswin and Henderson model were best fit at 27°C with RSS = 1.929×10^-5, SEE = 0.00011, R² = 0.99531 and RSS = 0.001192, SEE = 0.00011, R² = 0.9807 for polythene and petri-dish respectively. Oswin model was best fit for both storage conditions at 37°C and 40°C. The monolayer moisture content at the three temperatures ranged from 0.0193 - 0.0752 and the general model observed for this study that could predict the sorption behavior of Bambara-corn chips was Oswin model.

Drying characteristics of non-centrifugal sugar

Non-centrifugal sugar (NCS), generally known in most parts of Asia as jaggery, is a commonly used sweetener in food preparations. Sun drying of NCS has been reported to improve its shelf life. However, there is no systematic study, supported by relevant data and analysis, for this claim. In this article, the influence of temperature and relative humidity (RH) of the medium on the drying rate of jaggery is studied. The optimum drying temperature and humidity for jaggery of different compositions are determined. Jaggery containing low levels of reducing sugars (RSs) (2–5%) has lower equilibrium moisture content (EMC). For this reason, moisture could be reduced to as low as 0.5% within 250 minutes. Case-hardening is realized for the product with low RS content (typically ≤ 6%), and it does not allow one to employ high temperatures for drying. For jaggery containing high RS (10–15%), case-hardening was not evident, while the higher EMC does not permit moisture reduction below 4–5% under otherwise similar conditions.

The effect of thermo-mechanical treatment of moso bamboo (Phyllostachys Pubescens) on its sorption and physicomechanical properties

The aim of this study was to examine some properties of heat-treated (200 °C) and densified (treated) bamboo. Density (ρ), equilibrium moisture content (EMC), sorption hysteresis (H), swelling (S), and Brinell hardness (HB) were examined and compared with untreated bamboo (Phyllostachys sp.) and common oak (Quercus robur L.). The density of heat-treated bamboo (ρ = 1170 kg/m3) was higher than that of untreated bamboo (ρ = 850 kg/m3) and oak wood (ρ = 670 kg/m3). The sorption isotherms were parameterized with the Guggenheim-Anderson-deBoer (GAB) model. Treated bamboo showed lower EMC than untreated bamboo and oak wood in the entire hygroscopic range. The swelling anisotropy index of treated bamboo was the lowest (1.09). The mean HB of treated bamboo (HB=132 MPa) was significantly higher than that of oak and untreated bamboo.

The effect of encapsulants on the heat of sorption in vacuum-dried cajá powder

Equilibrium moisture data from the powdered pulp of Spondias mombin, L., both with and without additives - 58% maltodextrin (MD) or 58% gum arabic (GA) - were determined at 20, 30, 40 and 50 °C, using the static gravimetric method for a water activity range of 0.06 to 0.90. The resulting isotherms were sigmoidal and typical Type III, with the Guggenheim-Anderson-de-Boer model (GAB) adjusted to the experimental data for equilibrium moisture vs water activity. The addition of additives was shown to affect the isotherms in such a way that, for the same water activity, samples of CP+GA and CP+MD showed a lower equilibrium moisture content and were not affected by the variations in temperature. The isosteric heat of sorption for the caja powder with additives was greater (less negative) than that of the caja powder with no additives, suggesting that polar sites in the product without the addition of GA or MD are more active. An empirical exponential relationship can describe the dependence of the heat of sorption as a function of the moisture content of the material.

Chemical Composition and Selected Physical Properties of Oak Wood (Quercus robur L.) Modified by Cyclic Thermo-Mechanical Treatment

Oak wood (Quercus robur L.) was subjected to cyclic thermo-mechanical treatment (CTMT). The temperature of the press platens during the CTMT was either 100 °C or 150 °C. The equilibrium moisture content and the dimensional changes of the oak wood were examined when it was exposed to 9 to 98% relative humidity at 20 °C (± 2 °C). Densified oak wood had lower equilibrium moisture content than the non-densified wood for the relative humidity ranges examined. Furthermore, when the temperature of the thermo-mechanical modification was higher, the equilibrium moisture content of the wood was lower. Thermo-mechanical modified wood was characterised by higher swelling values in the radial direction than in the tangential direction. When the temperature of the CTMT was higher, the water absorption of the wood was lower. The number of treatment cycles significantly influenced the water absorption of the oak wood at its maximum saturation. After CTMT, changes were observed in oak wood, in particular, with regards to soluble substances in 1% NaOH and to chloroform-ethanol extractives.