Effects of moisture content on formaldehyde emission and mechanical properties of plywood

Aydın, İsmail; Çolakoğlu, Gürsel; Çolak, Semra; Demirkır, Cenk

doi:10.1016/j.buildenv.2005.05.011

Cited by 73 publications

(52 citation statements)

References 2 publications

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“…An increase in SG (beech and birch plywood) causes more adhesive to be used to make the boards and consequently releases more formaldehyde. Moreover, Aydin et al (2006) reported that the FE from poplar and spruce plywood decreased with increasing veneer moisture content. On the other hand, Nemli and Öztürk (2006) found that increasing SG, shelling ratio, and pressure increased the FC of PB.…”

Section: Effect Of Wood Drying On Formaldehyde Emissionsmentioning

confidence: 99%

Understanding of Formaldehyde Emissions from Solid Wood: An Overview

Salem¹,

Böhm²

2013

BioResources

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Wood is known to contain and emit volatile organic compounds including formaldehyde. The emission of formaldehyde from wood increases during its processing to lumber and wood-based panels (i.e., particleboard and fiberboard). This increased emission can be attributed to the processing procedure of wood, which includes drying, pressing, and thermo-hydrolysis. Formaldehyde is emitted from wood under very high heat and is not expected to be a significant source of the emissions from composite wood products during normal service. Formaldehyde is also detectable even if wood has never been heated as well as under more or less ambient conditions. The presence of formaldehyde in the emissions from wood that does not contain adhesive resin has been explained by thermal degradation of polysaccharides in the wood. The emission levels of formaldehyde depend on factors such as wood species, moisture content, outside temperature, and time of storage. Additionally, the pyrolysis of milled wood lignin at 450 °C yields benzaldehyde, and the pyrolysis of spruce and pinewood at 450 °C generate formaldehyde, acetaldehyde, 2-propenal, butanal, and butanone, which can be attributed to the breakdown of the polysaccharide fraction of the wood. Keywords INTRODUCTIONThe European Union, the USA, China, and Japan now have legislation regulating the allowed levels of formaldehyde emission (FE) from wood and wood-based products, and without doubt there will be increased focus and controls placed on products that are known to release formaldehyde (Salthammer et al. 2010). The main sources of FE from wood-based products such as medium density fiberboard (MDF), particleboard (PB), and plywood are the resins used, such as urea-formaldehyde (UF), melamine-modified urea formaldehyde (MUF), and phenol-formaldehyde (PF) (Salem et al. 2011a). Solid wood grown in normal forest conditions releases low levels of formaldehyde, particularly during the manufacturing process (Salem et al. 2012a). Furthermore, PF resins are frequently used in the manufacture of cork products. For this reason, formaldehyde and phenol are often measured together (Horn et al. 1998 Formaldehyde is a naturally occurring chemical in wood, as wood contains a diminutive, but still detectable amount of free formaldehyde. Formaldehyde can be formed from the main components of wood (cellulose, hemicelluloses, and lignin) as well as from its extractives (Schäfer and Roffael 2000) to different extents depending on the boundary conditions (pH value, temperature). On the other hand, the inorganic substances in wood do not directly contribute to formaldehyde release.The FE from solid wood increases at elevated temperatures and prolonged heating times (Schäfer and Roffael 2000), even in the absence of wood resin (Jiang et al. 2002). On the other hand, the degree of polymerization of cellulose seems to have no significant influence on the emission of formaldehyde; also, raising the temperature to 100 and 150 °C, the formaldehyde liberation from starch is also very low even at high reaction ...

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Section: Effect Of Wood Drying On Formaldehyde Emissionsmentioning

confidence: 99%

Understanding of Formaldehyde Emissions from Solid Wood: An Overview

Salem¹,

Böhm²

2013

BioResources

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“…Obvious variations in formaldehyde emission were found among the panels and within panels of the same type of PB and MDF, which was in agreement with previous investigations (Wiglusz et al 2000;Salem et al 2012b;Roffael et al 1979). Additionally, Aydin et al (2006) reported that poplar and spruce plywood formaldehyde emissions decreased with increasing veneer moisture content.…”

Section: Free Formaldehyde Valuesmentioning

confidence: 99%

Norway Spruce (Picea abies [L.] Karst.) as a Bioresource: Evaluation of Solid Wood, Particleboard, and MDF Technological Properties and Formaldehyde Emission

Salem¹,

Zeidler²,

Böhm³

et al. 2013

BioResources

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Norway spruce (Picea abies [L.] Karst.) is an important forest species, comprising approximately 55.9% of the growing stock of Czech forests. The variations in the wood densities from three different locations were evaluated with respect to their mechanical and physical properties. Also, mechanical properties and formaldehyde emission of particleboard (PB) and medium-density fibreboard (MDF) panels produced from Norway spruce wood were investigated. The overall average density of the spruce wood was 509.22 kg/m 3 , ranging from 400.95 ± 27.92 to 617.50 ± 29.91 kg/m 3 by location. Most of the panels exceeded the requirements of EN standards for the measurements of MOE, MOR, and the internal bond. Furthermore, the results showed highly significant differences (p < 0.001) among the panels for PB and MDF, which could be related to inter-panel variations. The formaldehyde emissions of PB and MDF were below the E1 emission limits. Moreover, positive correlations were found between the formaldehyde emissions (perforator and gas analysis methods) and board density. The results of this study verify our knowledge of wood density variation as affected by location as well as the age of trees and their relationship to mechanical and physical properties. Consequently, the variation in mechanical properties of the produced panels as well as the formaldehyde emission can further contribute to creating models to predict the quality of the product.

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“…Before this building code, the concentrations of formaldehyde were higher than the guideline at the completion of houses in many cases. And some investigations showed that the concentrations of formaldehyde do not decrease with time soon [3][4][5][6][7][8]. Organic compounds are volatizing from building materials and from furniture and articles which are carried into houses by residents, so the indoor concentrations do not decrease with the aging of houses.…”

Section: Introductionmentioning

confidence: 99%

Decline of VOC Concentrations with the Aging of Houses in Japan

Hayashi¹,

Osawa²

2013

JEP

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The purpose of this investigation is to know the long-term characteristics of VOC concentrations in houses built before the building code in 2003 and to clarify the countermeasures against indoor air pollution in the houses already built. For example, the improvements of living habits, ventilation and the remove of building materials. The concentrations of VOCs were measured in these houses in summer and winter from 2000 to 2005. The results showed that the concentration of formaldehyde decreased in the first year. After that the decline of the concentration was not seen and the concentration changed only with the temperature. The characteristics of decline were thought to be caused by two sorts of emission. One is an emission of concealed formaldehyde in the process of material production and the other is an emission with the generation of formaldehyde from adhesives of urea resin and moisture. The concentration of toluene decreased rapidly in the first year. The concentrations of xylene, ethyl-benzene and styrene showed a similar change. But the concentrations of acetaldehyde which were measured from the summer of 2002 did not decrease and its concentration in some houses was higher than the guideline even in the winter of 2005.

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Effects of moisture content on formaldehyde emission and mechanical properties of plywood

Cited by 73 publications

References 2 publications

Understanding of Formaldehyde Emissions from Solid Wood: An Overview

Understanding of Formaldehyde Emissions from Solid Wood: An Overview

Norway Spruce (Picea abies [L.] Karst.) as a Bioresource: Evaluation of Solid Wood, Particleboard, and MDF Technological Properties and Formaldehyde Emission

Decline of VOC Concentrations with the Aging of Houses in Japan

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