Low-density Boards Research Articles

Determination of Physical and Mechanical Properties of Waste Paper Boards Supported by Wood Chips and Chopped E-glass Fiber

Today, legal regulations, along with social awareness, have made waste management a necessity. Depending on the type of waste, technological developments have enabled an increase in the number of approaches, e.g., reusing, recycling, and manufacturing of different products. In this study, low-density boards were produced using different proportions of office waste paper, wood chips, and chopped E-glass fiber. Waste paper and glass fiber formed the middle layer of the boards and wood chips comprised the surface layers. The density, water absorption, and thickness swelling properties of the boards were investigated. Among the mechanical properties, the modulus of rupture, modulus of elasticity, and internal bond strength were determined. The use of wastepaper led to a reduction in the modulus of rupture and modulus of elasticity of the boards. An increase in the glass fiber ratio contributed positively to the water absorption and thickness swelling properties, whereas it directly led to decreases in the internal bond strength, and the modulus of rupture and modulus of elasticity values. Nonetheless, the low-density boards were able to meet the minimum modulus of rupture and modulus of elasticity specified in ANSI 208.1 standards, while only one variation met the IB requirements.

Production of Particleboard Using Various Particle Size Hemp Shives as Filler

Research was performed into the use of hemp shive as a fast-growing and carbon-storing agricultural waste material in the production of particleboard for the construction industry. Hemp shives were acquired and prepared for board production with the use of milling and sieving to reach two target groups with 0.5 mm to 2 mm and 2 mm to 5.6 mm particle size ranges. The cold pressing method was used to produce hemp boards with Kleiberit urea formaldehyde resin as a binder. The boards were made as 19 mm thick single-layer parts with a density range of 300 ± 30 kg/m3, which qualifies them as low-density boards. Exploratory samples were made using milled hemp fibers with higher density. Additional components such as color pigments and wood finishes were added to test improved features over raw board samples. Tests were performed to determine moisture contents, density range, structural properties, and water absorption amounts. Produced board bending strength reached 2.4 MPa for the coarser particle group and thermal conductivity of 0.057 ± 0.002 W/(mK). The results were compared with existing materials used in the industry or in the development stage to indicate options of developed board applications as indoor insulation material in the construction industry.

Evaluation of particle board production from cotton gin waste and urea-formaldehyde resin

The objective of this study was the evaluation of feasibility of producing particleboard for general use using cotton gin waste generated in Argentina and urea formaldehyde resin. The chemical composition and size distribution of particles of the ginning residue as well as mechanical and physical properties of the particleboards obtained were investigated. Density and flexural strength of particleboards produced with varying levels of urea-formaldehyde resin between 8.3 and 19.3% (solid to solid ratio) were evaluated. The effect of incorporating jute reinforcement on the mechanical properties of these boards was also analyzed. Particle boards with densities between 530 and 700 kg/m3 and variable flexural strength between 0.30 and 5.85 MPa were obtained, allowing the minimum levels required for low-density boards to be reached.

Low density hemp shive particleboards for latent thermal energy storage performance

Over the past few decades, climate change and the search for renewable energy sources have become hot topics within the research community. About 30% of the world's energy consumption is in the heating and cooling sector of residential buildings. Such materials can reduce the temperature variations, leading to an improvement in human comfort and decreasing at the same time the energy consumption of buildings. This paper assesses the integration of a microencapsulated phase change material (PCMs) with organic composite phase change as the core material and melamine-formaldehyde as the shell in hemp shive intended for building indoor wallboard. Paraffin waxes are cost-effective and have moderate thermal energy storage density but low thermal conductivity and, hence, require large surface area. Commercial manufactured organic PCM-S28 with a 25-29°C melting point received from MikroCaps Ltd. (Slovenia) has been used. The experimental boards were made using cold pressing technology and with 10% Kleiberit Urea Formaldehyde resin (UF) glue as a binding agent. The experimental boards were made 25 mm thick with a density of 310 ± 20 kg/m3 that qualify them as low-density boards. By adding 5% nanocapsules during the board manufacturing process, the heat capacity is increased by 28%.

Experimental Study of Using Micro-Encapsulated Phase-Change Material Integrated into Hemp Shive Wallboard

Phase change materials (PCMs) are now widely known as potential additives for building insulation materials to provide a thermal mass effect that helps conserve energy and maintain a comfortable indoor temperature. Therefore, the study presented in this paper focuses on an experimental investigation of the specific heat capacity and thermal conductivity of hemp shive mixed with PCMs. Industrially manufactured organic PCM-S50 received from MikroCaps Ltd. (Slovenia) has been used to further enhance respective properties of the product samples. The experimental boards were made from hemp shive by directly mixing 5% encapsulate PCMs into the mass. Cold pressing was used to manufacture the boards with Kleiberit urea formaldehyde resin glue as a binding agent. The experimental boards were made as 25 mm thick single-layer parts with a density of 300 ± 20 kg/m3, which qualify them as low-density boards. By adding nanocapsules during the board manufacturing process, the heat capacity is increased by 62%. Based on the great potential of using latent heat, it becomes a possible solution for the development of new technologies related to the automatic regulation of an indoor microclimate.

Формирование структуры плит малой плотности из гидродинамически активированных мягких отходов деревообработки

Wood boards find wide application in many fields, especially in house building. Research has been actively conducted in the field of obtaining low-density wood boards in the past 20 years. This article presents the results related to studying the influence of hydrodynamic processing of wood particles (sawdust) on their physical properties and dimensions, for the purposes of identifying the mechanism of autohesion interaction in formation of low-density boards without the binding agents. The particles were processed in a hydrodynamic rotarypulsed disperser. Water retention value (WRV) was used in order to evaluate the degree of processing. A method for determination of water adsorption by wood, and scanning electron microscopy were taken as a criterion of the fibrillation size of wood particles and increase inavailable interphase surfaces as a result of processing. Hydrodynamically processed wood pulp was frozen at –60 oС and then lyophilized in order to preserve its capillary structure. As a result of the study, we have constructed sorption isotherms of the following samples: initial sawdust, sawdust processed in the hydrodynamic disperser and lyophilized, and lowdensity wood boards. It was found out that the sorption isotherms of hydrodynamically processed and lyophilized wood particles are considerably different from the isotherms of initial sawdust and final boards. The calculations made according to the BET method showed that the specific surface area of the processed and lyophilized wood particles is about 350 m2/g of dry weight, and the area of the initial sawdust and obtained boards is approximately 130 m2/g of dry weight. This suggests that hydrodynamic processing allows us to considerably increase the fibrillation of wood particles, thereby increase the area of available interphase surfaces, which creates the conditions for autohesion interaction between the particles. As a result the board structure is formed without binding agents. Thedynamics of changes in the wood particles dimensions under hydrodynamic processing was studied by the scanning electron microscopy. Sawdust crushing and increasing the share of ribbon-shaped particles in the form of partially destroyed tracheids with fibrillated surfaces take place at that. The wood pulp becomes more homogeneous under the high degree of processing (water retention value by the Jaime method – 250 %).For citation: Ermolin V.N., Bayandin M.A., Kazitsin S.N., Namyatov A.V. Structure Formation of Low-Density Boards from Hydrodynamically Activated Soft Wood Waste. Lesnoy Zhurnal [Forestry Journal], 2019, no. 5, pp. 148–157. DOI: 10.17238/issn0536-1036.2019.5.148Funding: The study was carried out with the financial support from the Russian Foundation for Basic Research, the Government of Krasnoyarsk Krai, and the Krasnoyarsk Regional Fund for Scientific and Technical Development Support within the frame of a scientific project “Study of Structuring Materials made of cavitation activated wood”.

Physical and Mechanical Properties Evaluation of Particle Board Produced from Saw Dust and Plastic Waste

The current work reports on the fabrication of composite matrix from saw dust (SD) and recycled polyethylene terephthalate (PET) at different weight ratio by flat-pressed method. Wood plastic composites (WPCs) were made with a thickness of 15 mm after mixing the saw dust and PET followed by a three phase press cycle. Physical properties (Density, Water Absorption (WA) and Thickness Swelling (TS)) and Mechanical properties (Modulus of Elasticity (MOE) and Modulus of Rupture (MOR)) were determined base on the mixing ratios according to the standard. WA and TS were measured after 2 h and 24 h of immersion in water. The results showed that as the density increased, the SD content decreased from 90 % to 50 % into the matrix. However, WA and TS decreases when the PET content increased in the matrix. Remarkably, the MOE and MOR attained a maximum point at 964.199 N/mm2and 9.03 N/mm2respectively in 50 % SD content. In comparism with standard, boards D and E can be classified as medium density boards while A, B and C are low density boards. The results indicated that the fabrication of WPCs from sawdust and PET would technically be feasible for indoor uses in building due to favorable physical properties exhibited. The mechanical properties response showed that it cannot be used for structural or load bearing application.

Thermal failure time of non-loadbearing gypsum board assemblies in standard furnace tests

Gypsum board assemblies are important in preventing spread of flame and hot smoke, keeping escape routes available, and extending evacuation time. In general, heavier assemblies are expected to provide a higher degree of fire resistance, while low density board can reduce transportation and labor costs. The focus of this paper is to identify key model parameters that affect performance under fire conditions to enable design of lower weight board assemblies without compromising fire performance. A mathematical model was developed to estimate the thermal response of full scale 3-D gypsum wall assemblies subjected to ASTM E-119 furnace test conditions. The effect of insulation in the air cavity (including melting) was modeled. The estimated thermal response compared favorably with the measured experimental furnace test data. It was found that lots of factors were positively correlated with failure time. Among them, the board thickness, the activation energy of di-hydrate gypsum and hemi-hydrate gypsum had the most significant influence. When these factors were increased by 5% respectively, failure time was extended by 8.06%, 7.81% and 11.84% accordingly. Some factors were negatively correlated with failure time, such as the emissivity of anhydrous gypsum, the thermal conductivity and melt conductivity of insulation. Emissivity of the hemi-hydrate gypsum did not affect the failure time obviously.

Development of medium- and low-density fibreboards made of coconut husk and bound with tannin-based adhesives

Fibreboards made of coconut husk and bonded with tannin-based adhesives could represent an affordable building material in the Philippine for the low-income population. Coconut husk is a large available and not full-exploited byproduct of the coconut industry, and suitable tannins could be extracted from the bark of local tree species. Medium-density boards (700–800 kg m−3) were produced at the lab-scale and the influence of pressing cycle parameters, material preconditioning, and tannin adhesive formulation investigated and correlated to the chemical characteristics of the husk. Mimosa tannin adhesives with and without hardener (hexamine) and at different pH were considered. The produced board satisfied the mechanical requirements for the Japanese standard JIS A 5905 (Type 15) and showed also remarkably low-volatile emissions. An initial moisture content of the husk between 9 and 15% was necessary for an efficient adsorption of the adhesive. The presence of silica on the fibre surface enhanced the auto-condensation of tannin molecule reducing the need of hardener in the adhesive formulation. Low-density boards (250–300 kg m−3) were also produced. Their thermal conductivity (0.071–0.082 W m−2K−1) satisfied the requirement for JIS A 5905 Class A insulation boards.

Integrated utilization of grape skins from white grape pomaces

An approach for the integrated utilization of grape skins from white grape pomaces has been proposed. This consists of consecutive or simultaneous extraction of grape skins with neutral organic solvent and water under reflux. Organic extract is a valuable raw material for the isolation of oleanolic acid. The aqueous extract (ca 50%, w/w) is composed of essentially hexoses and suitable for the high yield (till 51%) bioethanol production at a maximum specific cell growth rate (μmax) of 0.29h−1. The remained extracted grape skins are the complex of structural polysaccharides embedded into cutinous matrix. Extracted grape skins were shown to be a prospective raw material for the production of low-density boards (d≤0.40) for insulation needs. The boards produced from grape skins and bind of 8% urea–formaldehyde resin revealed reasonable tensile strength (0.4MPa) and a low thermal conductivity (0.09–0.12W(mK)−1) over a wide range of temperatures (40–200°C).

The effect of sizing and paper structure on paperboard for retortable packaging

This thesis reports on an investigation of the mechanisms of edge wicking in retortable paperboard. Retortable board is used for packaging preserved food, a process which requires that the package and its contents be sterilised by exposure to high temperature steam for up to three hours. The board used must thus have higher water repellence than traditional liquid packaging. Water vapour that condenses on the cut edges on the outside of the board causes particular concern. The paperboards studied were made from refined and unrefined bleached softwood kraft pulp and from refined unbleached softwood kraft pulp in one or two plies with different sizing levels and structures. Samples of each of the boards were immersed in a water bath at 95 °C. Other samples from the same boards were exposed to a combination of saturated steam at 130 °C and condensed steam in a special apparatus developed for this purpose. The board samples were placed on a cooling plate to simulate the temperature gradient when a container of cold food is sterilised with heated steam. Still other samples were exposed to heated steam in the absence of condensation by hanging them freely in the apparatus. The extent of edge wicking in the boards was determined by gravimetric measurements and also by near-infrared (NIR) spectroscopy, a technique that yields more information about the moisture content profiles and the mechanisms of liquid sorption. The moisture content profiles of boards exposed to saturated steam in the absence of condensation show more uniform water uptake. This phenomenon can be explained by rapid vapour phase transport throughout the pore structure, followed by slower water uptake in the fibres. By contrast, in samples exposed to both heated steam and condensed steam, there was both liquid sorption in the fibre network and rapid vapour phase transport of the steam. The moisture content in those samples was much higher close to the edge and lower behind the liquid frontier. The edge wicking of high temperature water was greatest in board that was not fully sized, in low density board, and in board made from unrefined pulp. The greater edge wicking in board made from unbleached pulp can be accounted for in terms of its greater swelling potential. In the low density board and the board made from unrefined pulp, the lumens at the unsized edge and the weaker bonding strength are suggested to affect the results. Capillary sorption takes place in lumens and delaminated bonds at the edge and then any further propagation takes place entirely by fibre diffusion. Capillary sorption may also be important in damaged areas where broken fibre-fibre bonds are exposed to liquid. The weaker bonded area in low density board therefore also contributes to water sorption. Edge wicking in the boards placed on the cooling plate and exposed to a combination of saturated and condensed steam was of a different nature. For these samples, density was not an important factor. The difference is due to the different mechanism at work in this case, where the relative area of the edge exposed to condensed steam was larger in the high density boards than in the low density boards. In the high density boards, condensed steam was sorbed in the structure by diffusion in the fibre structure, whereas in low density boards, the dominant effect was vapour phase transport in the void spaces followed by water uptake in the fibres.

Determination of the in-plane wetting of a board structure using NIR spectroscopy

This thesis reports on an investigation of the mechanisms of edge wicking in retortable paperboard. Retortable board is used for packaging preserved food, a process which requires that the package and its contents be sterilised by exposure to high temperature steam for up to three hours. The board used must thus have higher water repellence than traditional liquid packaging. Water vapour that condenses on the cut edges on the outside of the board causes particular concern. The paperboards studied were made from refined and unrefined bleached softwood kraft pulp and from refined unbleached softwood kraft pulp in one or two plies with different sizing levels and structures. Samples of each of the boards were immersed in a water bath at 95 °C. Other samples from the same boards were exposed to a combination of saturated steam at 130 °C and condensed steam in a special apparatus developed for this purpose. The board samples were placed on a cooling plate to simulate the temperature gradient when a container of cold food is sterilised with heated steam. Still other samples were exposed to heated steam in the absence of condensation by hanging them freely in the apparatus. The extent of edge wicking in the boards was determined by gravimetric measurements and also by near-infrared (NIR) spectroscopy, a technique that yields more information about the moisture content profiles and the mechanisms of liquid sorption. The moisture content profiles of boards exposed to saturated steam in the absence of condensation show more uniform water uptake. This phenomenon can be explained by rapid vapour phase transport throughout the pore structure, followed by slower water uptake in the fibres. By contrast, in samples exposed to both heated steam and condensed steam, there was both liquid sorption in the fibre network and rapid vapour phase transport of the steam. The moisture content in those samples was much higher close to the edge and lower behind the liquid frontier. The edge wicking of high temperature water was greatest in board that was not fully sized, in low density board, and in board made from unrefined pulp. The greater edge wicking in board made from unbleached pulp can be accounted for in terms of its greater swelling potential. In the low density board and the board made from unrefined pulp, the lumens at the unsized edge and the weaker bonding strength are suggested to affect the results. Capillary sorption takes place in lumens and delaminated bonds at the edge and then any further propagation takes place entirely by fibre diffusion. Capillary sorption may also be important in damaged areas where broken fibre-fibre bonds are exposed to liquid. The weaker bonded area in low density board therefore also contributes to water sorption. Edge wicking in the boards placed on the cooling plate and exposed to a combination of saturated and condensed steam was of a different nature. For these samples, density was not an important factor. The difference is due to the different mechanism at work in this case, where the relative area of the edge exposed to condensed steam was larger in the high density boards than in the low density boards. In the high density boards, condensed steam was sorbed in the structure by diffusion in the fibre structure, whereas in low density boards, the dominant effect was vapour phase transport in the void spaces followed by water uptake in the fibres.

Manufacturing low density boards from waste cardboards containing aluminium

We tried to recycle waste Tetra Pak cardboards, which contain aluminium as a step in the prevention of the environmental pollution caused by municipal solid wastes and as methods of achieving economical worth from these. The composite prepared with urea–formaldehyde resin was harder relative to that prepared with polyvinyl acetate based glue. The target cardboard density and thickness were 0.5 g/cm 3 and 3.0 cm, respectively. We were unable to obtain information on the effect of matrix: resin ratio on hardness of materials. Samples were easily damaged by water, suggesting that these materials were not suitable for use in high-humidity media.

Heat-transfer process during hot-pressing of flakeboard

Hot-pressing is the main process in flakeboard manufacture. Studies in this field also emphasize the effect on the heat-transfer process of the following factors: hot-pressing temperature, original moisture content (MC), target thickness and target density. In this experiment, dynamic data of changes in temperature in mats can be logged through temperature transducers and a computer data log system. The results of the experiment indicate that the core temperature-time curve can be divided into three stages: a stage of a rapidly rising temperature, a stage of moisture vaporizing and a stage of a slowly increasing temperature. If the hot-pressing temperature or the original MC increases during the first stage, the temperature will increase at an accelerated rate. This rate of acceleration in thin or low-density boards is very high. During the second stage, increasing the hot-pressing temperature or decreasing the original MC can shorten the time used to vaporize moisture. In thin or low-density board, this time period is short. In the third stage the original MC does not affect the rate of temperature increase, while the effect of the other factors is the same as that at the first stage. Given different conditions, vaporization temperature in the mat changes.

Utilization of wastepaper to manufacture low density boards

Shredded newspaper, magazine, and office wastepaper, bonded with urea-formaldehyde (UF) and tannin paraformaldehyde (TP) adhesives both at 8% and 12% of resin solid contents, based on oven-dried weight of particles, were used to produce low-density boards in a series of laboratory scale experiments. Physical, mechanical and dimensional stability properties were analyzed according to ASTM D 1037-91. The target board density and thickness were 0.6 g/cm 3 and 0.8 cm, respectively. Office wastepaper and newspaper UF and TP-bonded boards, at 12% resin level, had the best mechanical properties. Office wastepaper boards also exhibited the best thickness swelling properties. The dimensional stability properties of UF-bonded boards were better than the TP-bonded boards. In general, as resin level increased from 8% to 12% both MOR and MOE values increased. A comparison between UF and TP-bonded boards showed that the former performed better, at the same resin level.

Characterization of thermal performance of fibrous insulations subject to a humid environment

The insulating capability of a typical Fiberglas insulation slab exposed to different types of environment on each side of the slab was evaluated, based on theory that takes into account heat conduction, natural convection, phase changes, and gas infiltration. The results are analyzed and combined with recent theoretical work to find useful heat transfer characteristics for each of the material studied. These included RA-24 insulation, high-density wool; R-11 Batt insulation, low-density wool; RA-22 insulation, low-density board; and roof deck insulation, high-density board. 5 refs.

紙の伸縮安定性に及ぼす繊維間空げきの影響

Handsheets with different densities were prepared by TAPPI Standards, and expansivity and swelling stress of these sheets were measured. The effect of Interfiber space on the dimensional stability of papers was discussed. The results obtained are summarized below.1. Papers made from unbeaten or slightly beaten pulps containing a small amount of residual hemicellulose, such as linter pulp and alkali extracted LBKP, were rather poor in dimensional stability as compared with chemical pulps of paper making grade, but they did not increase in dimensional instability even when they were made from highly beaten pulps.2. On the contrary, papers made from chemical pulps of paper making grade greatly in-creased in dimensional instability with excessive beating of the pulp. Paper made from ground-wood pulp which contained a large amount of short fiber was also poor in dimensional stability.3. These pulps were roughly categorized into three groups according to their adsorptivities : linter pulp group, paper grade chemical pulp group and groundwood pulp group. Absorptivity depends on the chemical component of the pulps.4. For low density boards, moist-expansivity of the boards made from high C. S. freeness pulps as measured by thickness was larger than boards having the same density from low C. S. freeness pulps. But for high density boards, there were no appreciable differences in moist-expansivity among boards made from pulps of several degrees of C. S. freeness.5. A similar tendency was found in acid hydrolysis of pulps. That is, moist-expansivity of boards from unhydrolyzed pulp was larger than boards from acid hydrolyzed pulps for low density, but there were no appreciable differences in moist-expansivity among boards from these pulps for high density.6. The moist-expansivity of paper of low density was largely affected by the kind of pulp, but there was no significant difference at high densities.7. Swelling stresses due to absorbing water greatly correlated with the density of the boards and could be calculated by the following formula; y=a·xb (x : density of board, y : swelling stress) Swelling stresses of several pulps were in the following order.hardwood BKP > linter pulp, softwood BKP > softwood GP > softwood BSP8. Swelling stress of pulp was guessed to be higher than 1.5 ton/g, pulp in the case of density of 1.5, so it was very difficult to make the paper free from moist- or wet-expansion. In conclusion, it is most effective to increase interfiber space in the paper in order to make paper having high dimensional stability.