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Effects of acetylation on the dimensional stability and decay resistance of kenaf (Hibiscus cannabinus L.) fiberboard
1996 - IRG/WP 96-40059
The objective of this study was to investigate the influence of the acetylation treated kenaf fiber, Phenol formaldehyde resin content level, and three fungi species on the dimensional stability and decay resistance of high density non wood composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness, length changes, and decay resistance of the high density kenaf fiberboards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Rowell

Ancillary properties of vapor boron-treated composites
2001 - IRG/WP 01-40210
This paper discusses the water absorption, thickness swelling, and internal bond strength of North American composites treated using a vapor boron treatment process. For oriented strandboard, high boron loadings led to lower internal bond strength and lower thickness swelling. Water absorption results were variable but no deleterious effect of treatment was noted. For medium density fiberboard, the highest loadings led to reduced internal bond strength. Thickness swelling decreased with increasing boron level, but not significantly. As with OSB, water absorption results varied.
W A Jones, H M Barnes, R J Murphy

Worldwide in-ground stake test of acetylated composite boards
1997 - IRG/WP 97-40088
Acetylated wood composite stakes are being tested in ground contact (graveyard test) in seven fields around the world. Three types of acetylated wood composites were prepared: spruce fiberboard in Sweden, aspen fiberboard in Madison and rubber wood particle board in Indonesia. Two levels of acetylation were used, a high level of ~20% acetyl content and a low level of 10% acetyl content. Control boards of unmodified wood fiber/particle were also included. Stakes for the in-ground testing were taken from the boards and the size of each stake was 5x30x1.25 cm3. The stakes were put out in four continents: one test field in USA, one in New Zealand, two in Indonesia and three in Sweden. After three years of testing, results show that acetylation of wood provides excellent protection against fungal attack and minimizes swelling.
R M Rowell, B S Dawson, Y S Hadi, D D Nicholas, T Nilsson, D V Plackett, R Simonson, M Westin

Performance of Oriented Strandboard, Medium Density Fiberboard, Plywood, and Particleboard Treated with Tebuconazole in Supercritical Carbon Dioxide
2005 - IRG/WP 05-30364
The performance of oriented strandboard (OSB), medium density fiberboard (MDF), particleboard and plywood treated with tebuconazole using supercritical carbon dioxide was investigated over a 48 month exposure under harsh above ground conditions in Hilo, Hawaii. Samples treated to low retentions (<0.20 kg/m3) tended to experience decay at rates that were only slightly lower than those found with untreated controls. This was particularly true with aspen OSB, which failed within 30 months regardless of treatment level. Most other samples treated to higher retentions remained free of fungal decay over the test period. Tebuconazole treated Douglas-fir plywood provided the best performance, demonstrating the benefits of combining a moderately durable heartwood with supplemental preservative treatment. The results indicate that SCF-treated wood provides reasonable performance in non-soil exposures under severe decay conditions.
J J Morrell, M N Acda, A R Zahora

Tool wear for vapor boron-treated composites
2001 - IRG/WP 01-40209
A series of composites, including oriented strandboard and medium density fiberboard, were treated via vapor boron technology. Treated samples were compared to untreated composites using a tool force measuring technique. Tool forces measured with a dynamometer indicated a positive effect of boron addition. Visual and SEM examination indicated a wider wear zone on the rake face of the tool for the untreated material. Boron transfer to the tool material was confirmed by SEM.
W A Jones, H M Barnes, H A Stewart, R J Murphy

Accidental mold/termite testing of high density fiberboard (HDF) treated with borates and N’N-naphthaloylhydroxylamine (NHA)
2003 - IRG/WP 03-10462
High density fibreboard (HDF) was made from beech and pine furnish (50:50) and treated with boric acid (0.1-3%), borax (0.1-3%) or N&apos;-N-(1,8-naphthalyl) hydroxylamine (NHA) (0.1-1%) prior to gluing with urea formaldehyde (UF) resin in order to determine resistance to Eastern subterranean termites (Reticulitermes flavipes Kollar), the most economically important termite species in North America. HDF and southern yellow pine (SYP) sapwood specimens were tested in a modified no-choice soil-block test normally used for fungal decay tests for 5 weeks. Within the first week of incubation, all HDF specimens were heavily overgrown with a variety of mold fungi. This same contamination was not seen in regular SYP specimens tested under the same conditions. Mold contamination did not appear to inhibit termite attack in any measurable way. Weight loss in control HDF specimens was 28% after 5 weeks while weight loss in control SYP was 12% under similar test conditions. Selected treatments with boric acid, borax, didecyl dimethyl ammonium chloride (DDAC) and NHA reduced termite attack in HDF and SYP specimens below 5% weight loss. Synergy was not observed for boron containing compounds and NHA. We conclude that i) soil contact accelerates HDF mold contamination and termite damage in the absence of termidicides ii) HDF made with UF is more susceptible to moisture acquisition and mold contamination than SYP iii) NHA does not act as a mildewcide iv) 3% borates retard both mold and termite damage; and v) HDF is less durable, and requires more preservative to protect, than SYP.
S N Kartal, H H Burdsall Jr, F Green III

Surface color and roughness characteristics of medium density fiberboard (MDF) panels treated with fire retardants
2008 - IRG/WP 08-40420
The objective of this study was to determine surface characteristics and color change properties of Medium Density Fiberboard (MDF) treated by fire retardants (FR) with 10% concentration. Experimental panels were made using by melamine ureaformaldehyde (MUF) adhesive having 10%, 15%, 20% of melamine. The surface properties of the samples were determined using a fine stylus technique. Three roughness parameters, namely average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) were determined from the surface of the samples. Color change properties of MDF samples were evaluated to CIE L*a*b* methods by a spectrophotometer (Minolta CM-2600d). It was found that the surface roughness values of the FR treated MDF panels were higher than those of control panels. The highest surface roughness values obtained from MDF panels treated with MAF+BA+NPB, MAF+BA+BX, the lowest values obtained from MDF panels treated with MAF+AL. Also surface roughness of the MDF panels improved with increasing melamine additive rate in the MUF adhesive. According to CIEL*a*b method, color change properties of the samples showed variation as function of chemicals type. Especially, while the highest color change(?E) were determined for MDF samples treated with MINPB and MAF+BA+NPB, the lowest color change (?E) were obtained from MDF samples treated with MAF+AL, MIN.
D Ustaömer, M Usta, S Hiziroglu

The Effects of Some Fire Retardant Chemicals on the Decay Resistance of Medium Density Fiberboard (MDF)
2010 - IRG/WP 10-30536
The objective of this study was to determine the decay resistance of Medium Density Fiberboard (MDF) treated with 5% and 10% concentration of various fire retardant (FR) chemicals. Experimental panels were produced using by melamine-urea-formaldehyde (MUF) resins having 10%, 15% and 20% of melamine content. MDF specimens were subjected to decay resistance test performed according to modified EN 113 standard method using white-rot fungus, Trametes versicolor. It was found that the weight loss (%) of MDF specimens treated with chemicals were lower than those of control panels. Especially, the best results were obtained from MDF specimens treated with zinc borate (ZB). Furthermore, decay resistance of the MDF specimens improved with increasing melamine content in the MUF resin and increasing chemical concentration.
D Ustaömer, M Usta, Ü C Yildiz, S Yildiz, E D Tomak

Effects of Nano-Wollastonite on Ignition Time Reduction in MDF
2012 - IRG/WP 12-40576
Effects of wollastonite nano-fibers on ignition time reduction in medium density fiberboard were studied. Nanowollastonite was applied at 5, 10, 15, and 20 g/kg dry weight basis of wood fibers and compared with control specimens. Two application methods of nanowollastonite were used: surface application, and internal application. Specimens of 150×130×9 mm were prepared and the ignition times were measured using two apparatuses: slide fire test apparatus and fixed fire test apparatus. The obtained results indicated that treatments with higher nanowollastonite contents tended to have significant higher ignition times. Internal application of nanowollastonite resulted in an outstanding improvement in the ignition time tested by slide fire test apparatus. It can be concluded that 10% of nanowollastonite gives an ultimate improvement in ignition time.
H Reza Taghiyari, H Rangavar, P Noori, A Karimi

Investigating the potential role of creosote oil for the water repellent purposes in fiberboards
2013 - IRG/WP 13-40635
Effect of wood steaming during fiber generation processes and creosote oil on the properties of fiberboard, manufactured from creosote treated solid wood were investigated. Pulp fiber was generated by alkaline pretreatment of waste creosote impregnated wood which being fiberized by laboratory defibrator, atmospherically. These fibers blended with 0, 15, 30, 45 and 100 percent by weight of wood virgin fiber; generated at high steam pressure treatment. All fiber mixtures formed, dried and hot pressed to produce 3mm(d:1g/cm3) nominal thickness hardboard. Acidified creosote oil (free of high molecular weight poly aromatic hydrocarbons) was added to each fiber composition distinctly to evaluate and compare specifications with creosote free board specimens. All specimens were tested physically and mechanically to evaluate the effect of oil presence and wood steam treated fiber ratios on water absorption and thickness swelling after 2&24 hours submersion in distilled water. The results showed that creosote is responsible to decrease water uptake and thickness swelling of wood-based composite materials effectively and steam treatment in comparison to sodium hydroxide as precursor of fiber disintegration, is more efficient to improve both physical and mechanical properties of the fibrous sample boards.
M Sheikholeslami

Nano-Zycosil in MDF. Part I: Gas and Liquid Permeability
2014 - IRG/WP 14-40652
Effects were studied of zycosil nanoparticles, with size range from 20 to 80 nm, on liquid and gas permeability of medium density fiberboard. Nanozycosil was used at four consumption levels of 0, 50, 100, and 150 g/kg dry wood fibers. Density of all treatments was kept constant at 0.67 g/cm3. The obtained results indicated that the addition of zycosil to the mat resulted in a significant increase in gas permeability due to the lower fiber-content in the nanozycosil-treated specimens and the consequent micro-cavities that were formed in the boards. However, the water-repellant property of zycosil nanoparticles compensated for the micro-cavities to some extent. High correlation was observed between gas and liquid permeability. The consumption level of 50 g of nanozycosil/kg can be recommended to improve the impermeability property of medium density fiberboard to water.
H Reza Taghiyari, A Karimi, P M D Tahir, O Schmidt, E Bari, P Nouri , A Jahangiri

Effect of silver nanoparticles on the rate of heat transfer to the core of the medium-density fiberboard mat
2014 - IRG/WP 14-40653
Effect of silver nanoparticles on the rate of heat transferred to the core section of medium-density fiberboard (MDF) mat was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL/kg based on the weight of dry wood fibers; the results were then compared with the control MDF panels. The size range of silver nanoparticles was 30-80 nm. Results showed that the uniform and even dispersion of nanoparticles throughout the MDF-matrix significantly contributed to the faster transfer of heat to the core section. As to the loss of mat water content after the first 3 – 4 minutes under the hot press, the core temperature slightly decreased in the control panels. However, heat-transferring property of silver nanoparticles contributed in keeping the core temperature rather constant in the NS150 and 200 treatments. As to the de-polymerization of part of the resin in the surface layers of the mat due to the rapid absorption of heat from hot plates by the nanoparticles, it can be concluded that the optimum nano-suspension content should not necessarily be the highest one.
H Reza Taghiyari, O Schmidt, E Bari, P M Tahir, A Karimi, P Nouri, A Jahangiri

Effect of Nano-Silane on Permeability in MDF as a Result of Susceptibility to Moulds and Fungi
2016 - IRG/WP 16-40716
Effects were studied of vapor chamber on specific gas permeability of nanosilane-treated medium-density fiberboards (MDF). Size range of nanoparticles was 20 – 80 nm. Nano-silane (NS) was used at four consumption levels of 0, 50, 100, and 150 g/kg dry wood fibers. Density of all treatments was kept constant at 0.67 g/cm3. Specimens were kept for 18 weeks in vaporized chamber; their specific gas permeability was measured every two weeks. Results showed that extreme moisture uptake due to the biological structure of wood fibers, as well as mold and fungi growth on the specimens from the tenth weeks, resulted in the breaking down of the urea-formaldehyde resin; they also weakened the water-repellant effect of NS; consequently, the permeability increased significantly. It can be concluded that NS makes MDF susceptible to molds and therefore NS-treated MDF panels are not recommended for moist climates in which boards are exposed to water vapors in the air for a long time.
H R Taghiyari, J Norton, A Moradiyan, M Sadegh Taher Tolou Del, H Siahposht, B Moradi-Malek, M Noferesti