Impregnation of Wood with Microencapsulated Bio-Based Phase Change Materials for High Thermal Mass Engineered Wood Flooring

Phase-Change-Material-Impregnated Wood for Potential Energy-Saving Building Materials

PCMs (phase change materials) are ideal for thermal management solutions in buildings. This is because they release and store thermal energy during melting and freezing. When this material freezes, it releases a lot of energy in the form of latent heat of fusion or crystallization energy. Conversely, when the material melts, it absorbs the same amount of energy from its surroundings as it changes from a solid to a liquid state. In this study, Oriental spruce (Picea orientalis L.) sapwood was impregnated with three different commercial PCMs. The biological properties and the hygroscopic and thermal performance of the PCM-impregnated wood were studied. The morphology of PCM-impregnated wood was characterized through the use of scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). PCM-impregnated wood demonstrated low performance in terms of storing and releasing heat during phase change processes, as confirmed by DSC. The results show that PCMs possess excellent thermal stability at working temperatures, and the most satisfying sample is PCM1W, with a phase change enthalpy of 40.34 J/g and a phase change temperature of 21.49 °C. This study revealed that PCMs are resistant to wood-destroying fungi. After the 96 h water absorption test, the water absorption of the wood samples decreased by 28%, and the tangential swelling decreased by 75%. In addition, it has been proven on a laboratory scale that the PCM material used is highly resistant to biological attacks. However, large-scale pilot studies are still needed.

Effect of Number of Impregnations of Microberlinla sp with Microcapsule Emulsion on the Performance of Self-Repairing Coatings on Wood Surfaces

Embedding melamine-formaldehyde (MF) resin-coated shellac microcapsules in waterborne coatings can extend the service longevity of waterborne coatings on a wood surface to a certain extent. Due to the content limitation of self-repairing microcapsules in waterborne coatings, the effective self-healing performance time is short. With the aim of improving the self-repairing properties of self-repairing coatings on the surface of a Microberlinla sp substrate, a more effective self-healing mechanism was achieved by impregnating the ebony wood substrate several times with an MF resin-coated transparent shellac-rosin microcapsule emulsion. After the impregnation of the ebony boards with microcapsules, a waterborne acrylic resin coating containing 3.0 wt.% transparent shellac microcapsules was applied to the surface of the wood boards. The influence of the number impregnations on the surface coating’s physical properties, chemical properties, and self-repairing properties was explored. The results showed that the hardness of the surface coating on the ebony boards changed little under different numbers of impregnations. With the increasing number of impregnations, the surface coatings’ adhesion and impact strength slowly increased, the chromatic difference value was increased, and the roughness first increased and then decreased. Impregnating ebony boards with the microcapsule emulsion contributes to enhancing the aging resistance and repair performance of surface coatings on the ebony boards. When the number of impregnations was eight, the width change rate of cracks on surface self-healing coatings was 28.4%, which suggested the best repair performance among all samples. By impregnating the wood substrate with the self-healing microcapsule emulsion, the effect of the interaction between microcapsules and wood on the self-repairing properties of the surface coating was studied, contributing to the theory for further improving the self-repairing properties of waterborne coatings on wood surfaces and promoting the application and development of self-healing microcapsules.

Bio-Based Phase Change Materials for Wooden Building Applications

Solid wood can serve multifunctionality for energy savings in buildings. The study reveals the results of biodeterioration and degradation of solid Scots pine wood used to incorporate single or multicomponent fatty acid mixtures as bio-based phase change materials (BPCMs). The sapwood samples were impregnated with capric acid (CA), methyl palmitate (MP), lauryl alcohol (LA) and a mixture of coconut oil fatty acids and linoleic acid (CoFA-LA). The samples were tested against subterranean termites by an Italian species (Reticulitermes lucifugus), the wood boring beetle Hylotrupes bajulus and mold through a discoloration test. Tested against termites, the impregnated samples were significantly less susceptible to the attack than the controls, i.e., the tested BPCMs were resistant to R. lucifugus. The only test with MP terminated at the moment against H. bajulus showed positive results with no larvae surviving. The mold discoloration test revealed that the wood impregnated with CoFA-LA was identically susceptible to mold discoloration when compared to the control, nonimpregnated samples. This pioneer study verifies that solid wood employed for the encapsulation of BPCMs for building purposes can serve identically or somewhat better than similar wooden building elements regarding attacks of the above microorganisms and insects. Such multifunctional building elements will be tested further in a pilot scale building to characterize better the durability aspects of the new materials.

Modeling of Falling Ball Impact Test Response on Solid, Veneer, and Traditional Engineered Wood Floorings of Several Hardwoods

Hardness is a key mechanical property of flooring materials. In this study, the performance of veneer floorings (with a top layer thickness of 0.6 mm) was investigated by dynamic hardness tests, comparing it with those of traditional engineered wood floorings (with a top layer thickness of 3 mm) and solid wood floorings. Two hardwoods commonly used on wood flooring, viz. Quercus robur L. and Hymenaea courbaril L., and two fast-growing hardwoods, Eucalyptus globulus Labill. and Eucalyptus grandis W. Hill ex Maiden, were tested as top layers. To compare their usage properties, a dynamic impact hardness test involving steel balls with three diameters and five different drop heights was carried out, measuring the footprint diameter (FD) and the indentation depth (ID). The data from 4800 impacts, corresponding to 180 different individual groups (4 hardwood species × 3 ball diameters × 5 drop heights × 3 floor types) were analyzed. The results showed that the general response in terms of both FD and ID was better in the engineered wood floorings than in solid wood floorings, and that the veneer floorings (0.6 mm) showed better behavior than traditional engineered wood floorings (3.0 mm). Furthermore, for the veneer floorings, the two fast-growing hardwood species tested, which have significantly different densities, showed similar behavior to traditional hardwoods, suggesting that they would be suitable for valorization in the wood flooring industry.

Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years

Increasing the use of wood in buildings is regarded by many as a key solution to tackle climate change. For this reason, a lot of research is carried out to develop new and innovative wood surface improvements and make wood more appealing through features such as increased durability, fire-retardancy, superhydrophobicity, and self-healing. However, in order to have a positive impact on the society, these surface improvements must be applied in real buildings. In this review, the last five years of research in the domain of wood surface improvements and modifications is first presented by sorting the latest innovations into different trends. Afterward, these trends are correlated to specifications representing different normative, ecologic and economic factors which must be considered when expecting to introduce a wood treatment to the market. With this review, the authors hope to help researchers to take into consideration the different factors influencing whether new innovations can leave the research laboratory or not, and thereby facilitate the introduction of new wood surface treatments in the society.

Mechanical and Optical Properties of Thermochromic Reversible Waterborne Primer Film on Tilia europaea with 1,2-Benzo-6-diethylaminofluorane Based Microcapsules

A waterborne thermochromic primer film containing thermochromic reversible microcapsules on the surface of Tilia europaea was prepared. The influences of different microcapsule concentrations on the reversible thermochromic, optical, mechanical and liquid resistance properties of the primer films were investigated. Not only were the morphology and structure of microcapsules and films observed, but also the chemical compositions of the microcapsules and films were analyzed. The results showed that for the primer film with microcapsules, the microcapsule concentration had a more significant influence on color difference. The primer film with microcapsules can achieve thermochromic reversibility. The temperature of color change was 32 °C and it had a good color recovery. The film gloss was negatively correlated with the microcapsule concentration, and the film with 5.0%-15.0% concentration had the best gloss. Adding an appropriate concentration of microcapsules can effectively improve the mechanical properties of the film. The film with 0-15.0% microcapsules had better liquid resistance to detergent, i.e., grade 1. The bonding form between the primer film added with microcapsules and Tilia europaea was physical bonding. This study provides a technical reference for the development of modern intelligent discoloration wood products.

Bio-Based Phase Change Materials Incorporated in Lignocellulose Matrix for Energy Storage in Buildings—A Review

Due to growing consciousness regarding the environmental impact of fossil-based and non-sustainable materials in construction and building applications, there have been an increasing interest in bio-based and degradable materials in this industry. Due to their excellent chemical and thermo-physical properties for thermal energy storage, bio-based phase change materials (BPCMs) have started to attract attention worldwide for low to medium temperature applications. The ready availability, renewability, and low carbon footprint of BPCMs make them suitable for a large spectrum of applications. Up to now, most of the BPCMs have been incorporated into inorganic matrices with only a few attempts to set the BPCMs into bio-matrices. The current paper is the first comprehensive review on BPCMs incorporation in wood and wood-based materials, as renewable and sustainable materials in buildings, to enhance the thermal mass in the environmentally-friendly buildings. In the paper, the aspects of choosing BPCMs, bio-based matrices, phase change mechanisms and their combination, interpretation of life cycle analyses, and the eventual challenges of using these materials are presented and discussed.

Thermal Characterization of Pinus radiata Wood Vacuum-Impregnated with Octadecane

The incorporation of phase change materials (PCM) in construction components has become an alternative to reduce the effect of thermal loads in buildings with low thermal inertia. This study put together the effective heat storage capacity of an organic phase change material (O-PCM, octadecane) with the construction and production potential of Pinus radiata in Chile. The wood is impregnated with octadecane by using the Bethell method, showing that it has good retention of the impregnator, and that its size was not modified. Differential scanning calorimetry analysis (DSC) showed that the composite material could achieve fusion enthalpy values from 36 (20.8 MJ/m3) to 122 J/g (108.9 MJ/m3). The transient line heat source method used, indicated that impregnation of Pinus radiata with octadecane increases its specific heat at temperatures from 15 to 20 °C, while its thermal conductivity decreases in the radial and the tangent directions, and increases in the longitudinal direction, showing a decrease in the orthotropic behavior of the wood. The ability of Pinus radiata wood to store latent heat positioned it as a candidate material to be considered in the building industry as a heat storage system.

A thermal energy storage composite by incorporating microencapsulated phase change material into wood

Phase change energy storage wood (PCESW) was prepared by using microencapsulated phase change materials (MicroPCM) as thermal energy storage (TES) materials and wood as the matrix.

Lignocellulosic Composites from Acetylated Sunflower Stalks

Sunflower stalks could be an alternative raw material for use in the particleboard industry since the requirements of P1 general purpose boards for use in dry conditions and P2 boards for interior fitment for use in dry conditions are easily satisfied. Acetylation of sunflower stalks is found to greatly improve the thickness swelling (TS) value, with acetylated boards showing 19.7% weight gain, meeting the TS requirements of P3 Non-Load-Bearing—Humid and P4 Load Bearing—Dry criteria; however, acetylation adversely affects the internal bond strength (IBS). It is suggested that combinations of industrial wood chips with sunflower raw material may be used for the overall improvement performance of the particleboards.

Streamlined Life Cycle Assessment of an Innovative Bio-Based Material in Construction: A Case Study of a Phase Change Material Panel

Research Highlights: This is the first study that analyzes the environmental performance of wood-based phase change material (PCM) panels. Background and Objectives: Life cycle assessment (LCA) is a powerful environmental management tool. However, a full LCA, especially during the early design phase of a product, is far too time and data intensive for industrial companies to conduct during their production and consumption processes. Therefore, there is an increasing demand for simpler methods to demonstrate a company’s resource efficiency potential without being data or time intensive. The goal of this study is to investigate the suitability of streamlined LCA (SLCA) tools and methods used in the building material industry, and to assess their robustness in the case study of a wood-based PCM panel. Materials and Methods: The Bilan Produit tool was selected as the SLCA tool and a matrix LCA was selected as the most commonly used SLCA method. A specific case study of a wood-based PCM panel was selected with a focus on its application in building construction in the province of Québec. Results: As a semi-quantitative LCA method, the matrix LCA provided a quick screening of the product life cycle and its hotspot stages, i.e., life cycle stages with high impact. However, the results of the full LCA and SLCA tools were quantitative and based on scientific databases. The use of the PCM panel and heating energy had the highest environmental impacts as compared to other inputs. The results of the full LCA and SLCA also identified energy consumption as a hotspot. Insufficient material or processes in the SLCA databases was one of the reasons for the difference between the results of the SLCA and full LCA. Conclusions: The examined SLCA methods provided proper explanations for the bio-based material in construction, but several limitations still exist, and the methods should be improved to make them more robust when implemented in such a specific sector.