Dynamic Vapor Sorption Measurements Research Articles

Color Modifications of a Maxillofacial Silicone Elastomer under the Effect of Cigarette Smoke.

Although it is known (from the observations of medical professionals) that cigarette smoke negatively affects maxillofacial prostheses, especially through staining/discoloration, systematic research in this regard is limited. Herein, the color modifications of M511 maxillofacial silicone, unpigmented and pigmented with red or skin tone pigments, covered with mattifiers, or with makeup and mattifiers, and directly exposed to cigarette smoke, were investigated by spectrophotometric measurements in the CIELab and RGB color systems. The changes in color parameters are comparatively discussed, showing that the base silicone material without pigmentation and coating undergoes the most significant modifications. Visible and clinically unacceptable changes occurred after direct exposure to only 20 cigarettes. By coating and application of makeup, the material is more resistant to color changes, which suggests that surface treatments provide increased protection to adsorption of the smoke components. The dynamic water vapor sorption (DVS) measurements indicate a decrease of the sorption capacity in pigmented versus unpigmented elastomers, in line with the changes in color parameters.

Carbon Cloth Electrodes for Vanadium Redox Flow Batteries

Renewable energy sources such as wind and solar are playing an increasingly important role as the decarbonization of the energy industry moves forward. However, wind and solar-based energy production fluctuates daily and seasonally. For a stable electrical grid, a large-scale energy storage system is required. One promising technology for this is the Vanadium Redox Flow Battery (VRFB), developed in the late 1980s by Maria Skyllas-Kazacos (1), which has been continuously researched and improved over the last decades.VRFBs are already commercially available but must overcome significant lifetime and efficiency challenges. Polarization and pumping losses account for a large part of the efficiency losses due to the high flow-through resistance of the electrolyte in the electrode (2). Therefore, the electrode material must be optimized to achieve high catalytic activity and excellent flow properties to enhance the battery's performance.In a previous study, we identified key factors such as the electrode's structure, wettability, and electrochemical performance. Therefore, we developed a suitable set of characterization techniques (3). This multimodal characterization approach has been applied to evaluate woven and knitted carbon cloths. We designed electrode materials with specific fiber structures and weaving and knitting patterns. The raw material for the fibers is cellulose from hemp. To successfully commercialize VRVBs, the manufacturing process of the material must be low-cost and easy to fabricate on an industrial scale. Here, the electrode materials are fabricated by weaving or knitting, a well-established technique in the textile industry for centuries, and are ideally suited for the large-scale industrial production of electrodes. After weaving or knitting, the cloths are subsequently carbonized.To understand the influence of the fabrication pattern, the flow direction, and the 3D electrode structure on the flow behavior, we used Electrochemical Impedance Spectroscopy (EIS) coupled with the Distribution of Relaxation Times (DRT) analysis (4,5). This method allows simultaneously investigating the electrochemical performance, wettability, and structure in an application-oriented, in-house-designed setup. To develop a deeper understanding of the microscopic structure of the fiber and its influence on the key factors, Scanning Electron Microscopy (SEM) and nano-X-ray computed tomography (nano-CT) were utilized. These results were combined with Dynamic Vapor Sorption measurements (DVS), which are used to investigate the wettability of the material, and Cyclic Voltammetry (CV), which accesses the electrochemical performance. Additionally, we studied the effect of thermal activation on these parameters with EIS and DRT analysis, SEM, nano-CT, DVS, CV, and X-ray photoelectron spectroscopy.The materials presented in this paper exhibited excellent electrode performance, demonstrating good wettability, high catalytic activity, and large electrochemically active surface area. These are promising examples of electrode engineering as a pathway to optimal designs of VRFBs.1. M. Skyllas‐Kazacos, M. Rychcik, R. G. Robins, A. G. Fane and M. A. Green, J. Electrochem. Soc., 133(5), 1057–1058 (1986).2. N. Bevilacqua, L. Eifert, R. Banerjee, K. Köble, T. Faragó, M. Zuber, A. Bazylak and R. Zeis, Journal of Power Sources, 439, 227071 (2019).3. K. Köble, M. Jaugstetter, M. Schilling, M. Braig, T. Diemant, K. Tschulik and R. Zeis, Journal of Power Sources, 569, 233010 (2023).4. M. Schilling, M. Braig, K. Köble and R. Zeis, Electrochimica Acta, 430, 141058 (2022).5. M. Schilling and R. Zeis, submitted. Figure 1

Pyridazine‐Promoted Construction of Vinylene‐Linked Covalent Organic Frameworks with Exceptional Capability of Stepwise Water Harvesting

AbstractIn this study, we successfully developed two novel vinylene‐linked covalent organic frameworks (COFs) using 2‐connected 3,6‐dimethylpyridazine through Knoevenagel condensation. These COFs featured finely tailored micro‐/nano‐scale pore sizes, high surface areas and stable non‐polar vinylene linkages. Finely resolved powder X‐ray diffraction patterns demonstrated highly crystalline structures with a hexagonal lattice in the AA layer stacking. The resulting one‐dimensional channels possess strong hydrogen‐bond accepting sites arising from the decorated cis‐azo/azine units with two pairs of fully exposed lone pair electrons, endowing the as‐prepared COFs with exceptional water absorption properties. The g‐DZPH‐COF exhibited successive steep water uptake steps starting from low relative pressures (P/PSTA=0.1), with the remarkable water uptake capacity of 0.26 g/g at P/PSTA=0.2 (25 °C), which is the optimal value recorded among the reported COFs. Dynamic vapour sorption measurements revealed the fast kinetics of these COFs, even in the cluster formation process. Water uptake and release cycling tests demonstrated their outstanding hydrolytic stability, durability, and adsorption–desorption retention ability.

Pyridazine-Promoted Construction of Vinylene-Linked Covalent Organic Frameworks with Exceptional Capability of Stepwise Water Harvesting.

In this study, we successfully developed two novel vinylene-linked covalent organic frameworks (COFs) using 2-connected 3,6-dimethylpyridazine through Knoevenagel condensation. These COFs featured finely tailored micro-/nano-scale pore sizes, high surface areas and stable non-polar vinylene linkages. Finely resolved powder X-ray diffraction patterns demonstrated highly crystalline structures with a hexagonal lattice in the AA layer stacking. The resulting one-dimensional channels possess strong hydrogen-bond accepting sites arising from the decorated cis-azo/azine units with two pairs of fully exposed lone pair electrons, endowing the as-prepared COFs with exceptional water absorption properties. The g-DZPH-COF exhibited successive steep water uptake steps starting from low relative pressures (P/PSTA=0.1), with the remarkable water uptake capacity of 0.26 g/g at P/PSTA=0.2 (25 °C), which is the optimal value recorded among the reported COFs. Dynamic vapour sorption measurements revealed the fast kinetics of these COFs, even in the cluster formation process. Water uptake and release cycling tests demonstrated their outstanding hydrolytic stability, durability, and adsorption-desorption retention ability.

Transparent maltitol- cellulose nanocrystal film for high performance barrier

The broad applications of cellulose nanocrystal (CNC) films are restricted by their low resistance against water and brittleness. In this study, high barrier transparent films composed of CNCs and maltitol, used as a bio-plasticizer (at up to 30% weight), were prepared by spray deposition. Addition of plasticizer increased the optical transmittance of the films. It also improved elongation at break and flexibility of the films, while reducing Young’s modulus and tensile strength. The barrier properties of CNC films plasticized with maltitol were significantly improved over CNC. In particular, films containing 30 wt.% maltitol showed a water vapor permeability of 3.67 × 10–12 (g/Pa.s.m) and oxygen permeability of 4.75 (cm3.µm/m2.day.Pa) corresponding to 94% and 78% reductions over CNC films, respectively. This remarkable barrier improvement is attributed to a combination of decreased porosity and the interaction of hydroxy groups of maltitol and CNCs. This interaction led to a reduction of the free hydroxy groups available to interact with the water molecules diffusing in the nanocomposite films, as confirmed by dynamic vapor sorption measurements. This study presents maltitol as a green plasticizer significantly improving the CNC film properties and enabling new barrier applications.

Detection of helical water flows in sub-nanometer channels

Nanoscale flows of liquids can be revealed in various biological processes and underlie a wide range of nanofluidic applications. Though the integral characteristics of these systems, such as permeability and effective diffusion coefficient, can be measured in experiments, the behaviour of the flows within nanochannels is still a matter of speculation. Herein, we used a combination of quadrupolar solid-state NMR spectroscopy, computer simulation, and dynamic vapour sorption measurements to analyse water diffusion inside peptide nanochannels. We detected a helical water flow coexisting with a conventional axial flow that are independent of each other, immiscible, and associated with diffusion coefficients that may differ up to 3 orders of magnitude. The trajectory of the helical flow is dictated by the screw-like distribution of ionic groups within the channel walls, while its flux is governed by external water vapour pressure. Similar flows may occur in other types of nanochannels containing helicoidally distributed ionic groups and be exploited in various nanofluidic lab-on-a-chip devices.

Proton Transport Functionality-Enabled Carbon Support for Improved Fuel Cell Performance and Durability.

A novel Monarch carbon material with proton conduction capability due to the presence of sulfone/sulfoxide/sulfonic groups on the surface was evaluated as a potential cathode catalyst support to enable an electrode design with low ionomer content in proton exchange membrane (PEM) fuel cells. X-ray photoelectron spectroscopy of the carbon support confirmed the sulfonic acid functionality, while dynamic vapor sorption measurements proved higher water uptake. Electrochemical impedance spectroscopy of the PtCo/Monarch electrodes showed higher proton conductivity than state-of-the-art PtCo/C with decreasing ionomer to carbon (I/C) content due to the presence of sulfonic acid functional groups on the carbon support surface. Fuel cell performance and durability measurements showed better high-current density performance for PtCo/Monarch with a 75% lower ionomer content in the electrode compared to that of PtCo/C. Our studies indicate that Monarch carbon could be a viable alternative support for PEM fuel cell catalyst applications.

Discrepancy of Effective Water Diffusivities Determined from Dynamic Vapor Sorption Measurements with Different Relative Humidity Step Sizes: Observations from Cereal Materials

Water diffusivity, a critical parameter for cereal processing design and quality optimization, is usually concentration-dependent. dynamic vapor sorption (DVS) system provides an approach to establishing the relationship between water concentration and diffusivity. However, the usual relative humidity (RH) jump during practical sorption processes is usually greater than that adopted in DVS measurements. Water vapor sorption kinetics of glutinous rice grains, glutinous rice flour and wheat flour dough films were measured using the DVS system to verify if varying RH step sizes can obtain identical diffusivities within the same range. The effective diffusivities were determined according to Fick's second law. The results revealed that increasing RH step size led to a higher estimated diffusivity, regardless of whether the water concentration gradient or potential chemical gradient was considered a driving force for water diffusion. This finding was further confirmed by a linear RH scanning DVS measurement. The water concentration-dependent diffusivity obtained from a multi-step DVS measurement, according to Fick's second law, will overestimate the required time for practical cereal drying or adsorption. Thus, this paradoxical discrepancy needs a new mass transfer mechanism to be explained.

Physicochemical properties of charcoal aerosols derived from biomass pyrolysis affect their ice-nucleating abilities at cirrus and mixed-phase cloud conditions

Abstract. Atmospheric aerosol particles play a key role in air pollution, health, and climate. Particles from biomass burning emissions are an important source of ambient aerosols, have increased over the past few decades, and are projected to further surge in the future as a result of climate and land use changes. Largely as a result of the variety of organic fuel materials and combustion types, particles emitted from biomass burning are often complex mixtures of inorganic and organic materials, with soot, ash, and charcoal having previously been identified as main particle types being emitted. Despite their importance for climate, their ice nucleation activities remain insufficiently understood, in particular for charcoal particles, whose ice nucleation activity has not been reported. Here, we present experiments of the ice nucleation activities of 400 nm size-selected charcoal particles, derived from the pyrolysis of two different biomass fuels, namely a grass charcoal and a wood charcoal. We find that the pyrolysis-derived charcoal types investigated do not contribute to ice formation via immersion freezing in mixed-phase cloud conditions. However, our results reveal considerable heterogeneous ice nucleation activity of both charcoal types at cirrus temperatures. An inspection of the ice nucleation results together with dynamic vapor sorption measurements indicates that cirrus ice formation proceeds via pore condensation and freezing. We find wood charcoal to be more ice-active than grass charcoal at cirrus temperatures. We attribute this to the enhanced porosity and water uptake capacity of the wood compared to the grass charcoal. In support of the results, we found a positive correlation of the ice nucleation activity of the wood charcoal particles and their chemical composition, specifically the presence of (inorganic) mineral components, based on single-particle mass spectrometry measurements. Even though correlational in nature, our results corroborate recent findings that ice-active minerals could largely govern the aerosol–cloud interactions of particles emitted from biomass burning emissions.

Highly Polymorphic Materials and Dissolution Behaviour: The Peculiar Case of Rifaximin

Rifaximin is a locally acting antibiotic practically insoluble in water. It presents several crystal phases characterized by different degrees of hydration. The aim of this work is to investigate the dissolution behaviour of rifaximin α, β, and amorphous forms in relation to their relative thermodynamic stability to contribute to clarifying possible solvent- or humidity-mediated conversion patterns. Kinetic and intrinsic solubility were investigated along with particle size distribution, specific surface area, and external morphology. The solution and moisture mediated conversion from metastable α and amorphous forms to stable β form were elucidated by coupling intrinsic dissolution test with chemometric analysis as well as by dynamic vapour sorption measurements. The dissolution behaviour of the α form stems mainly from the transition to β form that occurs upon exposition to relative humidity higher than 40%. The α form converted more rapidly than the amorphous form due to the smaller supersaturation ratio. It can be concluded that, due to its marked tendency to transform into β form, the dissolution test for the α form, even if conducted according to compendial procedures, needs to be accompanied by a panel of further tests that allow to uniquely identify the solid phase under investigation.

Sequential polymer infusion into solid substrates (SPISS): Impact of processing on sorbent CO2 adsorption properties

Solid sorbents made of small amine molecules and polyamines infused into mesoporous substrates are promising materials for CO2 capture technologies. To date, their preparation is mainly based on wet infusion with focus on increasing amine content by varying the structure of the amine sorbent and designing solid substrates of various pore parameters. Less explored in the field are changes in processing to afford efficient CO2 sorbents. In this study, branched poly(ethylenimine) (bPEI, Mw = 800 Da) alone and blends with linear poly(propylenimine) (LPPI, Mn = 6,700 Da) are infused into solid SBA-15 substrates by a method that varies the solution processing called sequential polymer infusion into solid substrates (SPISS). The reference 40 % bPEI-SBA-15 samples are split by two methods: split batch in dry suspension (SBD) and split batch in liquid suspension (SBL). Sequentially, alcoholic 10% of bPEI (non-blends) and 10% of LPPI (blends) solutions are introduced to afford the desired products. Under dry conditions, the resulting 50% bPEI-SBA-15 SBD & SBL sorbents display high CO2 capacities up to 3.47 mmol CO2/gSiO2 for simulated flue gas (10% CO2) and 2.62 mmol CO2/gSiO2 for direct air capture (DAC, 400 ppm CO2). Under humid DAC conditions the CO2 performance is further enhanced with an uptake of 4.62 mmol CO2/gSiO2 and amine efficiency of 0.22 mmol CO2/mmol N. Subjected to extended temperature swing adsorption kinetic cycling (20 cycles), the SPISS samples display stable working capacities and retain over 70% (blends) and over 90% (non-blends) of their initial 12 h adsorption performance. LPPI is demonstrated to be an effective water sorption limiting agent using dynamic vapor sorption measurements. Solid state NMR techniques reveal important insights into the dynamics of the amine polymers confined into SBA-15 pores, as impacted by processing conditions. The results suggest that the conformation of the polymers is different depending on the processing method, displaying relatively tight (SBD) and loose (SBL) packing. The simple solution processing approaches presented here show that processing variations may guide the design of solid amine sorbents with desirable properties relevant for integration into CO2 capture technologies.

Investigation of Physical Properties of Disodium Etidronate Tetrahydrate and Application of Phosphorus K-Edge X-Ray Absorption Near-Edge Structure Spectroscopy.

Disodium etidronate is a bisphosphonate, compounds that are widely used in the treatment of bone disorders such as osteoporosis and Paget's disease. We investigated the physical properties of disodium etidronate tetrahydrate crystal, form I. We used X-ray powder diffraction (XRPD), thermal analysis, dynamic vapor sorption (DVS), X-ray single crystal structure analysis, and phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy for the first time. XRPD and thermal analyses demonstrated that form I was dehydrated and transformed to an amorphous form, to a crystalline form II, and finally to a form III by heating. DVS measurements revealed that the amorphous form, form II, and form III were rehydrated to form I by humidification, and form I was stable even at 0% relative humidity. These results indicate that form I is the most stable solid-state under ambient conditions and is suitable as an API for manufacture in solid formulations. The phosphorus K-edge XANES spectra differed among form I, the amorphous form, and form II, which may be ascribed to the difference in the coordinate bond schemes between the phosphate moieties and sodium ions. The results demonstrated that the phosphorus K-edge XANES spectroscopy could be applied to the identification or the discrimination of crystal forms of the APIs containing phosphate moieties. Acquired information about physical properties are crucial for manufacturing of solid formulations of disodium etidronate. XANES spectroscopy is a promising alternative method for evaluating the solid-state forms of APIs.

Deswelling of microfibril bundles in drying wood studied by small-angle neutron scattering and molecular dynamics

Structural changes of cellulose microfibrils and microfibril bundles in unmodified spruce cell wall due to drying in air were investigated using time-resolved small-angle neutron scattering (SANS). The scattering analysis was supported with dynamic vapor sorption (DVS) measurements to quantify the macroscopic drying kinetics. Molecular dynamics (MD) simulations were carried out to aid in understanding the molecular-level wood-water interactions during drying. Both SANS experiments and simulations support the notion that individual cellulose microfibrils remain relatively unaffected by drying. There is, however, a significant decrease in fibril-to-fibril distances in microfibril bundles. Both scattering and DVS experiments showed two distinct drying regions: constant-rate drying and falling-rate drying. This was also supported by the MD simulation results. The shrinking of the fibril bundles starts at the boundary of these two regions, which is accompanied by a strong decrease in the diffusivity of water in between the microfibrils.Graphic abstract

Microscale Physical and Mechanical Analyses of Distemper Paint: A Case Study of Eidsborg Stave Church, Norway

ABSTRACT This study focuses on the use of micro-sensitive methods – nanoindentation, dynamic water vapour sorption, and X-ray microtomography – to examine the physical properties of small volumes of artists’ materials. The novel methodology proposed in this paper was tested on laboratory-prepared chalk-based ground samples and subsequently applied to distemper paint samples taken from the polychrome walls of Eidsborg stave church. This article discusses key parameters that can be used to inform macro-sized mock-ups mimicking physical and mechanical behaviour of artistic materials, and highlights limitations of such an approach for highly heterogeneous paint systems. Dynamic water vapour sorption measurements allowed determination of the pigment volume concentration (PVC) of distemper paint from Eidsborg stave church as 95%. To the authors’ knowledge, this represents the first assessment of PVC for historic distemper paint using a non-destructive experimental technique, which can be extended to other hygroscopic samples of known composition.

Solid-State Dehydration Mechanism of Diclofenac Sodium Salt Hydrates

Salt formation is a useful technique for improving the solubility of active pharmaceutical ingredients (APIs). For instance, a nonsteroidal anti-inflammatory drug, diclofenac (DIC), is used in a sodium salt form, and it has been reported to form several hydrate forms. However, the crystal structure of the anhydrous form of diclofenac sodium (DIC-Na) and the structural relationship among the anhydrate and hydrated forms have not yet been revealed. In this study, DIC-Na anhydrate was analyzed using single-crystal X-ray diffraction (XRD). To determine the solid-state dehydration/hydration mechanism of DIC-Na hydrates based on both the present and previously reported crystal structures (4.75-hydrate and 3.5-hydrate), additional experiments including simultaneous powder XRD and differential scanning calorimetry, thermogravimetry, dynamic vapor sorption measurements, and a comparison of the crystal structures were performed. The dehydration of the 4.75-hydrate form was found to occur in two steps. During the first step, only water molecules that were not coordinated to Na+ ions were lost, which led to the formation of the 3.5-hydrate while retaining alternating layered structures. The subsequent dehydration step into the anhydrous phase accompanied a substantial structural reconstruction. This study elucidated the complete landscape of the dehydration/hydration transformation of DIC-Na for the first time through a crystal structure investigation. These findings contribute to understanding the mechanism underlying these dehydration/hydration phenomena and the physicochemical properties of pharmaceutical crystals.

Effect of Additives on the Sorption Kinetics of a Silica Gel Bed in Adsorption Chiller

The article presents experimental results of the metal-based and carbon nanotube additives influence on sorption kinetics of a silica-gel-based adsorption bed in an adsorption chiller. The purpose of the doping is to improve the efficiency of sorption processes within the bed by use of metallic and non-metallic additives characterized by higher thermal diffusivity than basic adsorption material. The higher the thermal conductivity of the bed, the faster the sorption processes take place, which directly translates into greater efficiency of the refrigerator. In this study, sorption kinetics of pure silica gel sorbent doped with a given amount of aluminum (Al) and copper (Cu) powders and carbon nanotubes (CNT) were analyzed. The tests were performed on DVS Dynamic Gravimetric Vapor Sorption System apparatus used for dynamic vapor sorption measurements. A decrease in the amount of adsorbed water was observed with an increase in the mass share of the additives in the performed studies. Experimental results show that, CNTs seems to be the most promising additive as the sorption process time was reduced with the smallest decrease in water uptake. Any significant reduction of adsorption time was noted in case of the Al addition. Whereas, in case of Cu doping, delamination of the mixture was observed.

Investigation of the water vapor sorption behavior of bamboo fibers with different sizes

Recently, the demand for sustainable materials has given rise to new research interest in the intrinsic properties and applications of bamboo and its derivatives. Hygroscopicity plays an important role in the application of bamboo, and it is known that the size of the material particles affects the hygroscopicity of the material. To further understand the effect of the particle size, the bamboo fiber with a simple structure was destroyed by grinding, then equilibrated and dynamic sorption was studied by dynamic vapor sorption measurements. The obtained moisture sorption isotherm results showed that the maximum value of the moisture content of 19.69% was obtained in the medium-size fiber (MF) and the minimum value of 15.76% was obtained in the severely ground fiber (SF). As expressed by the slope of the fitting curves, MF showed the highest hygroscopic ability for the relative humidity > 30%. In addition, the sorption isotherm data were fitted by the Guggenheim-Anderson-de Boer (GAB) model, and the fitting results indicated small changes in the fiber monolayer water content between the samples with different fiber sizes. The largest difference of 0.53% was observed between control-size fiber (CF) and medium-size fiber (MF). Therefore, it was concluded that the differences between the moisture contents of the fibers with different sizes are mainly due to the differences in multilayer water sorption.

Relationship between Surface Properties and Fiber Network Parameters of Eucalyptus Kraft Pulps and Their Absorption Capacity

Water absorption capacity is a key characteristic of cellulosic pulps used for different commodities. This property is influenced by the affinity of the pulp fiber surface with water, chemical composition of the pulp, morphology, and organization of fibers in the network. In this study, surface properties of six industrial Eucalyptus bleached kraft pulps (fluff pulps) dry-defiberized in a Hammermill, which were obtained by wood pulping and pulp bleaching under different production conditions, were studied while employing dynamic water vapor sorption and contact angles measurements. The absorption properties of air-laid pulp pads were analyzed following the absorbency testing procedure and the relationship between these properties and pulp’s chemical composition and fiber network structure were assessed by multivariate analysis. The results showed that the accessibility of the fiber surface is related to the reduction of the contact angles, but, at the same time, to the longer absorption time and less absorption capacity of the fiber network. Therefore, the absorption properties of the pulps are not necessarily directly related to their surface properties. Indeed, absorptivity is related to the surface chemical composition, fiber morphology, and fiber network structure. Thus, surface carboxylic groups promote total water uptake, resulting in better absorption capacity. Greater fiber coarseness and deformations (curl and kink) provide a less wettable surface, but a more porous network with higher specific volume, resulting in more absorbent air-laid formulations.

Vapor–Liquid Equilibrium of Aqueous Urea Solution from Dynamic Vapor Sorption Measurements at 283.15–343.15 K

Urea solution as a biopolymer denaturing agent and source of nitrogen fertilizer has a key role in some industries, and it seems necessary to study the phase behavior of this system. This work aims...

Quality Control of Thermally Modified Timber Using Dynamic Vapor Sorption (DVS) Analysis

The importance of thermal modification is increasing worldwide. Increased use of thermally modified timber (TMT) has resulted in a need for reliable quality control, comprising control of variation of the production within defined limits, allowing third-party control in the case of certification and the regulation of customer complaints and claims. Techniques are thus needed to characterise the modification of quality in terms of improved target properties of TMT during industrial production, and of TMT products that have been in service for an arbitrary time. In this study, we aimed to utilise dynamic vapor sorption (DVS) for this purpose. Norway spruce (Picea abies) and European beech (Fagus sylvatica) samples were thermally modified at different temperatures according to different heat treatment techniques: (1) the Silvapro process based on an initial vacuum; (2) an air heat treatment, whereby samples were wrapped in aluminium foil; (3) thermal modification of wood samples in the ambient atmosphere in a laboratory oven. Wood samples from closed processes were analysed for validation. TMT was characterised with respect to mass loss, colour and density. Mass loss of wood due to modification (MLTM) was correlated with factors derived from DVS analysis. The present DVS measurements suggest that the equilibrium wood moisture content (EMC95% RH), the time to reach 10% wood moisture content (t10% MC), and the elongation factor, c, derived from a logarithmic function, can serve as alternative parameters to characterise the quality of several thermal modification processes. Further studies are recommended using other wood species, different modification processes and further parameters gained from DVS measurements to understand the robustness and the predictive power of the applied technique.