The influence of particleboard resination on their internal bond strength

The influence of particleboard resination on their internal bond strength. The aim of the project was to investigate the main mechanical and physical properties of particleboards, especially focused on internal bond, in terms of their resination. For the tests, the particleboards have been produced in laboratory conditions with the following glue content: 7, 10, 15, 30 and 50%. Particular attention was paid for examining the mechanical property – tensile strength perpendicular to surfaces (Internal Bond – IB). In addition, there were investigated modulus of elasticity (MOE), modulus of rupture (MOR) density and density profile. In the light of above mentioned tests, there is no positive effect of improvement of tested parameters when raise resination over 30% when producing particleboards. With the resination increase from 7 to 50% a significant change (densification) of panels’ structure, as well as differences between face and core layers density have been found.

EFFECTS OF POLYMER ADDITIVES ON SOME MECHANICAL AND PHYSICAL PROPERTIES OF CEMENT BONDED PARTICLEBOARDS

The effects of some polymer additives, also called super plasticizers, on selected physical and mechanical properties of cement bonded particle board were investigated. Two different kinds of poly carboxylic ether (PF300, DX40) and a melamine based polymer (300M) were added to the wood cement mixture. The ratios of polymer additives to the wood cement mixture were 1%, 1.2% and 1.4%. Cement bonded particleboards were manufactured with wood/cement (w/w) ratio of 1:3; target density of 1300 kg.m-3, and CaCl2 content of 5%. The cement bonded particleboards were tested for water absorption (2 and 24 hour), thickness swelling (2 and 24 hour), bending stiffness and strength and internal bond strength. Results of the study showed that most of the polymer addition decreased water absorption and thickness swelling of the boards. Replacement of cement with polymers increased internal bond strength and bending stiffness of the boards while bending strength was slightly reduced. Use of small amount of super plasticizers significantly improves most of the board properties.

Some of the Physical and Mechanical Properties of Particleboard Made from Betung Bamboo (Dendrocalamus asper)

The objective of this study was to evaluate various physical and mechanical properties of experimental particleboard panels made from Asian giant bamboo (Dendrocalamus asper). Single layer panels having a density level of 0.75 g/cm3 from coarse and fine particles were used within the scope of this study. Thickness swelling, water absorption, surface roughness, and wettability characteristics of the samples were tested as physical properties while bending, internal bond strength, and screw withdrawal strength of the panels were considered for their mechanical properties. Resistance of the panels against termite and fungus were also determined. Based on the findings in the work both physical and mechanical properties of the panels made from coarse particles resulted in higher values than those made from fine particles with the exception of their internal bond strength. It appears that using fine particles in the panels enhanced their overall surface quality as well as wettability. Regarding biological deterioration of the samples, those made with coarse particles had better resistance. It seems that giant bamboo as a non-wood lignocellulosic species would have potential to be used as raw material to the manufacture value added particleboard with accepted characteristics.

Effect of Panel Moisture Content on Internal Bond Strength and Thickness Swelling of Medium Density Fiberboard

Wood-based products usually have serious limitations concerning contact with water, both because wood is a hygroscopic material and because the commonly used binder has low moisture resistance. This paper studies the effect of panel moisture content (MC) on the physico-mechanical properties of medium density fiberboards (MDF). Several commercial MDF boards produced in Europe were stored at room temperature and relative humidity (RH) for 9 weeks (approx. range 15–20 °C and 50–85% RH). Every week, a strip of each MDF board was cut out, divided into 5 × 5 cm test pieces and its internal bond strength (IB) was measured. A strong influence of MDF moisture content on internal bond strength was observed and therefore IB test pieces were stored in a climatic chamber (either at 20 °C, 55% RH and at 20 °C, 70% RH). A decreasing linear relation was established between IB and MC. It was found that this effect is reversible: after drying, internal bond strength rises again (following a slight hysteresis). This work reinforces the importance of conditioned storage before board properties analysis, as described in European Standard EN 319.

The potential of using forest waste as a raw material in particleboard manufacturing

Wood particles and a mixture of forest waste were investigated as raw material for the particleboard industry. Urea formaldehyde resin was used as the adhesive in the production of the particleboards. Some chemical (pH, dilute alkali solubility, hot and cold water solubility), physical (density, moisture, thickness swelling, and water absorption), mechanical (modulus of rupture, modulus of elasticity, internal bond strength, and screw holding strength) properties, as well as the contact angle values of the resulting particleboards were determined. Due to its needle litter and cone content, the forest waste exhibited a lower pH value and a higher content of extractive material than wood. Increasing the addition of forest waste led to significant reductions in the physical and mechanical properties of the particleboards. The addition of forest waste reduced the internal bond strength the most (56.6%), whereas the least reduction (15.7%) was in the value of screw holding strength perpendicular to the surface. The values of all panels except panel type F exceeded the minimum modulus of elasticity (1600 N mm-2) required for furniture production according to the EN 312-P2 standard. Results of the analyses showed that forest waste (10% and 20%) is a suitable renewable raw material source for panel production.

Low-Density Cardoon (Cynara cardunculus L.) Particleboards Bound with Potato Starch-Based Adhesive

In the present work, and for the first time, totally biosourced low-density particleboards were produced using cardoon particles (a no added value by-product from the Portuguese cheese making industry), bound with a potato starch adhesive. Different starch/cardoon ratios (0.6, 0.8, 1 and 1.2) were tested and the effect of different bio-based additives (chitosan, wood fiber and glycerol) on the performance of the adhesive system was evaluated. The best result was obtained for a formulation with a starch/cardoon mass ratio of 0.8, a chitosan/starch mass ratio of 0.05 and a water/starch mass ratio of 1.75. The particleboards produced had a density of 323 kg·m−3, internal bond strength of 0.35 N·mm−2 and thickness swelling of 15.2%. The values of density and internal bond strength meet the standard requirements of general-purpose lightweight boards for use in dry conditions according to CEN/TS 16368 specification. Moreover, the susceptibility of the formulations with best results was established against subterranean termites and one decay fungi.

Selected Properties of Overlaid Magnesium Based Composite Panels for Flooring

The objective of this work was to evaluate some of the mechanical and physical properties of the flooring materials manufactured from panels having magnesia substrate overlaid with oak veneer (Querqus alba) and linoleum sheets. Commercially manufactured panels were used in this work. Bending characteristics, internal bond strength, thickness swelling, and surface quality of the samples were evaluated. The highest modulus of elasticity (MOE) value of 4406 MPa for the sample type-A2 was loaded in the direction of the substrate followed by 3478 MPa for linoleum covered samples which were loaded in the same direction. Internal bond strength values of the panels did not show any significant differences from each other. Dimensional stability of the specimens in the form of thickness swelling for both 2-h and 24-h water soaking tests resulted in values ranging from 0.11 to 0.19%. The surface quality of the samples was not substantially influenced as a function of water exposure. Based on the results in this work magnesium substrate overlaid with oak veneer and linoleum panels could have potential to be used as flooring material with accepted properties.

Effects of Flat-Shaped Face Layer Particles and Core Layer Particles of Intentionally Greater Thickness on the Properties of Wood-Reduced Particleboard

Against the background of the intention to reduce the amount of wood used in the production of particleboard for economic reasons, the associated reduction in panel density and consequently the panel properties, the influence of the alternative use of flat-shaped face layer particles and core layer particles of intentionally greater thickness on the panel properties was investigated. Appropriate particles were made for this purpose, panels with typical (650 kg/m3) and reduced wood usage (500 kg/m3) were produced, and e.g., their bending properties and internal bond strength were determined. Particle size characterization was done with sieve analysis, image analysis (length and width measurement), and manual thickness gauging. It was found that the alternative use of the flat-shaped particle significantly increased the bending properties and thus the level of the reference can be achieved despite the reduced use of wood. The reason for the increased bending properties was assumed to be the higher strength of the particles themselves and the more effective adhesive bond between the particles. The increase in internal bond strength when using alternative particles could be attributed solely the different production history (e.g., use of fresh cutting blades and laboratory scale production).

Sifat Papan Partikel Bambu Petung (Dendrocalamus asper) dan Bambu Wulung (Gigantochloa atroviolacea) dengan Perlakuan Ekstraksi

Bambu memiliki kandungan ekstraktif dengan persentase yang berbeda antar jenis bambu. Penelitian ini bertujuan untuk mengetahui pengaruh perlakuan ekstraksi pada jenis bambu yang berbeda terhadap sifat papan partikel. Dua jenis bambu digunakan yaitu Bambu Petung (Dendrocalamus asper) dan Bambu Wulung (Gigantochloa atroviolacea). Perlakuan ekstraksi digunakan pada partikel bambu sebelum proses pembuatan papan partikel yaitu tanpa ekstraksi, ekstraksi air dingin dan ekstraksi air panas. Papan partikel dibuat dalam ukuran 25 cm x 25 cm x 0,7 cm, target kerapatan 0,9 g/cm3, jumlah asam sitrat 30%, serta kondisi pengempaan suhu 180°C selama 10 menit. Hasil penelitian menunjukkan bahwa interaksi perlakuan ekstraksi dan jenis bambu hanya berpengaruh signifikan pada sifat penyerapan air dan keteguhan rekat internal, sedangkan jenis bambu berpengaruh signifikan pada nilai kadar air, modulus patah dan modulus elastisitas. Semua papan partikel yang dihasilkan memenuhi standar Japanese Industrial Standard (JIS) A 5908 tipe 13. Pada penelitian ini, papan partikel dari bambu wulung tanpa perlakuan ekstraksi mempunyai nilai yang memenuhi standar tipe 18 dan berpotensi sebagai bahan baku untuk produk furnitur eksterior. Perlakuan ekstraksi dapat meningkatkan secara signifikan nilai keteguhan rekat internal papan partikel bambu petung, walaupun secara umum dengan jumlah asam sitrat 30% perlakuan tersebut tidak diperlukan pada papan partikel bambu Properties of Particleboard made from Petung Bamboo (Dendrocalamus asper) and Wulung Bamboo (Gigantochloa atroviolacea) Particles with Extraction TreatmentAbstractBamboo has extractives, which the percentage of extractive was different based on bamboo species. This research aimed to investigate the effect of extraction treatment at different bamboo species on the particleboard properties. Two types of bamboo were used, i.e. Petung bamboo (Dendrocalamus asper) and Wulung bamboo (Gigantochloa atroviolacea). Three extraction treatments were conducted to the bamboo particles before the particleboard manufacture, i.e. unextracted, cold-water extraction, and hot-waterextraction. The particleboard was made in the size of 25 cm x 25 cm x 0.7 cm, target density of 0.9 g/cm³, citric acid content of 30%, and pressing temperature of 180°C for 10 min. The results showed that the interaction between extraction treatment and bamboo species significantly affected on the water absorption and internal bond strength, however bamboo species affected significantly on the moisture content, modulus of rupture, and modulus of elasticity. All of particleboards could met the requirement of the 13 type of Japanese Industrial Standard (JIS) A 5908. In this research, particleboards made from wulung bamboo particles without extraction treatment have properties that met the requirement of the 18 type and the products have potential to be as exterior materials for furniture. In general, an extraction treatment was not an important step on the manufacturing of bamboo particleboard using citric acid 30% as adhesive. However, the extraction treatment could increase significantly the internal bond strength of particleboard made from petung bamboo.

Influence of Adding Offcuts and Trims with a Recycling Approach on the Properties of High-Density Fibrous Composites

The sizeable global production of wood-based products requires new sources of raw material, but also creates large quantities of wastes or composites that do not comply with requirements. In this study, the influence of different shares of recovered high-density fiberboards (HDF-r), reversed into the production, on industrial HDF properties, has been examined. HDF-r may be a suitable partial substitute for raw pinewood for industrial HDF production. Although most of the mechanical properties, as well as thickness swelling and water absorption, had a linear decrease with the increase in the share of HDF-r share, the elaborated boards met most of the commercial requirements (EN 622-5). The property that did not meet the requirements was the internal bond strength for panels with 10% of HDF-r. The presented results show that, after some adjustments, it should be possible to produce HDF boards with up to 10% of recycled HDF being able to meet all commercial requirements.