Thermophysical Properties of Larch Bark Composite Panels

Krišťák, Ľuboš; Ružiak, Ivan; Tudor, Eugenia Mariana; Barbu, Marius Cătălin; Kain, Günther; Réh, Roman

doi:10.3390/polym13142287

Cited by 20 publications

(25 citation statements)

References 83 publications

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“…Such materials are, among several other used natural alternatives such as bark, cellulose, hemp, kenaf, flax, feathers, sheep wool, or wood fibers [ 7 , 19 , 20 , 21 ], the natural vegetable fiber-based thermal insulations that are gaining ground in the construction market [ 22 ] because demand for green building materials is rising sharply [ 23 ]. Among natural fibers, one of the most researched materials is the use of straw bales as building materials [ 24 , 25 ] because of their low thermal conductivity and high specific heat capacity, and hence low thermal diffusivity and good thermal insulation capability, especially with fibers randomly oriented and perpendicular to heat flow, and low environmental impact if the straw bale selection used for the straw-based building is suitable [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

“…In the case of the first base model [ 45 ], the material density and the bulk density of the insulation were sufficient because the glass fibers are both solids. However, the influence of the density and porosity of the heat transfer in natural-based materials also depends on the type of raw materials as well as the size and orientation of fibers, particles, or grains [ 19 , 51 ]. In the case of straw stems, one more density parameter must be introduced to take into consideration the porosity of the stems and the gaps among the stems.…”

Section: Introductionmentioning

confidence: 99%

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Heat Transfer in Straw-Based Thermal Insulating Materials

2021

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An analytic-empirical model was developed to describe the heat transfer process in raw straw bulks based on laboratory experiments for calculating the thermal performance of straw-based walls and thermal insulations. During the tests, two different types of straw were investigated. The first was barley, which we used to compose our model and identify the influencing model parameters, and the second was wheat straw, which was used only for validation. Both straws were tested in their raw, natural bulks without any modification except drying. We tested the thermal conductivity of the materials in a bulk density range between 80 and 180 kg/m3 as well as the stem density, material density, cellulose content, and porosity. The proposed model considers the raw straw stems as natural composites that contain different solids and gas phases that are connected in parallel to each other. We identified and separated the following thermal conductivity factors: solid conduction, gas conduction in stem bulks with conduction factors for pore gas, void gas, and gaps among stems, as well as radiation. These factors are affected by the type of straw and their bulk density. Therefore, we introduced empirical flatness and reverse flatness factors to our model, describing the relationship between heat conduction in stems and voids to bulk density using the geometric parameters of undisturbed and compressed stems. After the validation, our model achieved good agreement with the measured thermal conductivities. As an additional outcome of our research, the optimal bulk densities of two different straw types were found to be similar at 120 kg/m3.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat Transfer in Straw-Based Thermal Insulating Materials

2021

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“…The EDPS (Extended Dynamic Plane Source) method was used to measure physical properties. It is one of the non-stationary methods for this purpose [32, EDPS method is based on the Dynamic Plane Source (DPS) method, andit can be investigate the thermal conductivity, thermal diffusivity and specific heat capacity conductivity materials (λ ≤ 2 W•m −1 •K −1 ) [34,35]. Figure 5 shows the device scheme The EDPS (Extended Dynamic Plane Source) method was used to measure thermophysical properties.…”

Section: Thermophysical Propertiesmentioning

confidence: 99%

“…It is one of the non-stationary methods for this purpose [32,33]. The EDPS method is based on the Dynamic Plane Source (DPS) method, andit can be used to investigate the thermal conductivity, thermal diffusivity and specific heat capacity of low-conductivity materials (λ ≤ 2 W•m −1 •K −1 ) [34,35]. Figure 5 shows the device scheme.…”

Section: Thermophysical Propertiesmentioning

confidence: 99%

Influence of Flame Retardant Impregnation on Acoustic and Thermophysical Properties of Recycled Technical Textiles with the Potential for Use in Wooden Buildings

et al. 2021

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This article presents the results of an investigation of acoustic and thermophysical properties of insulation panels made from recycled technical textiles originating from the automotive industry. Measurements were performed on the samples of insulation panels (Senizol AT XX2 TL60), which were modified with liquid flame retardants (ISONEM® ANTI-FIRE SOLUTION, ECOGARD® B45, HR Prof). Another method of treatment was carried out by surface application of non-flammable facing (woven carbon fibre, nonwoven carbon fibre). Retardants were applied to the samples by surface spraying and soaking. The results showed a high ability of material to absorb sound in the frequency range 350 Hz–2 kHz. The sound absorption coefficient ranged from 0.82 to 0.9 in the frequency range 500 Hz–2 kHz. The noise reduction coefficient is 0.75. After material modification with the flame retardants, there was no significant change of sound absorption. The thermal conductivity coefficient of material before modification was 0.038 W⋅m−1⋅K−1. After application of the flame retardants, the thermal conductivity coefficient increased depending on type and method of retardant application in the range of 2.6–105.3%. The smallest change was detected after modification of material with ECOGARD® B45.

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“…The thermal conductivity value of the developed sample was 0.293 W/mK. In addition, some researchers have reported the valorization of tree bark fiber for thermal insulation panels, such as spruce, black locust, larch, and poplar bark [ 16 , 17 , 18 , 19 , 20 , 21 ]. These investigations showed that bark residue is a potential alternative raw material for efficient bio-based thermal insulation.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Thermal Bio-Insulation Materials Based on Oil Palm Wood: The Effect of Hybridization and Particle Size

et al. 2021

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Oil palm wood is the primary biomass waste produced from plantations, comprising up to 70% of the volume of trunks. It has been used in non-structural materials, such as plywood, lumber, and particleboard. However, one aspect has not been disclosed, namely, its use in thermal insulation materials. In this study, we investigated the thermal conductivity and the mechanical and physical properties of bio-insulation materials based on oil palm wood. The effects of hybridization and particle size on the properties of the panels were also evaluated. Oil palm wood and ramie were applied as reinforcements, and tapioca starch was applied as a bio-binder. Panels were prepared using a hot press at a temperature of 150 °C and constant pressure of 9.8 MPa. Thermal conductivity, bending strength, water absorption, dimensional stability, and thermogravimetric tests were performed to evaluate the properties of the panels. The results show that hybridization and particle size significantly affected the properties of the panels. The density and thermal conductivity of the panels were in the ranges of 0.66–0.79 g/cm3 and 0.067–0.154 W/mK, respectively. The least thermal conductivity, i.e., 0.067 W/mK, was obtained for the hybrid panels with coarse particles at density 0.66 g/cm3. The lowest water absorption (54.75%) and thickness swelling (18.18%) were found in the hybrid panels with fine particles. The observed mechanical properties were a bending strength of 11.49–18.15 MPa and a modulus of elasticity of 1864–3093 MPa. Thermogravimetric analysis showed that hybrid panels had better thermal stability than pure panels. Overall, the hybrid panels manufactured with a coarse particle size exhibited better thermal resistance and mechanical properties than did other panels. Our results show that oil palm wood wastes are a promising candidate for thermal insulation materials.

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Thermophysical Properties of Larch Bark Composite Panels

Cited by 20 publications

References 83 publications

Heat Transfer in Straw-Based Thermal Insulating Materials

Heat Transfer in Straw-Based Thermal Insulating Materials

Influence of Flame Retardant Impregnation on Acoustic and Thermophysical Properties of Recycled Technical Textiles with the Potential for Use in Wooden Buildings

Characterization of Thermal Bio-Insulation Materials Based on Oil Palm Wood: The Effect of Hybridization and Particle Size

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