Long-term development of VOC emissions from OSB after hot-pressing

Abstract

An oriented strand board (OSB) made of Scots pine (Pinus sylvestris L.) was tested for volatile organic compound (VOC) emissions 24 h after the hot-pressing process over a period of 2 months. The predominant emissions from the OSB were monoterpenes and aldehydes. Terpene emissions decreased continuously, whereas aldehyde concentrations initially increased and subsequently decayed. Aldehydes are formed by the autoxidative splitting of unsaturated fatty acids contained in the wood. Due to the delayed release of aldehydes, a comparison of different emission test results is only possible if age and storage conditions are clearly specified. For a reduction in VOC emissions from wood-based materials, wood properties, manufacturing process, and storage conditions have to be considered.

Fungal pretreatment of pine wood to reduce the emission of volatile organic compounds

“…Monoterpenes are metabolic products originating from the oleoresin of the living tree while aldehydes are typical secondary VOC that are usually formed after tree logging through autoxidation processes of unsaturated fatty acids (mostly linoleic, linolenic and oleic acid) and their derivates present in wood (Svedberg et al 2004). Therefore, terpene emissions from freshly logged conifers (or from wood products containing fresh softwood) are constantly declining, while aldehyde emissions usually show an initial increase followed by decline (Makowski et al 2005). It has been reported that aldehydes and monoterpenes from logged conifers (or from softwood-based products) are emitted at similar rates for a certain period of time.…”

Wood-Based Materials

“…The emission of terpenes, however, decreases with increasing temperature and the proportion of small-area particles in the surface layers of OSB can also reduce the terpene release [91]. Apart from the release of furfural, MAKOWSKI and OHLMEYER [91,92] observed that with increasing warming, fewer aldehydes are emitted, which they attribute to a progressive polymerization of free unsaturated fatty acids, through whose autooxidative splitting the release of aldehydes occurs. This reaction proceeds less well for polymerized large molecules than for small molecules.…”

“…With the exception of formaldehyde, the spectrum of compounds emitted from wood-based materials is not fundamentally different from that of wood; however, due to the effective temperatures during pressing, a shift of the terpenes towards the aldehydes and carboxylic acids Figure 39. Possible gas-phase and particulate emissions from wood-based materials (modified from [95]) occurs -i.e., substances which are released from nonvolatile or low-volatile wood components through thermal and/or oxidative reactions [91,92,114]. A potential problem for wood-based materials is posed by the subsequent release of furfural, as this substance is evaluated comparatively stringently in emission studies through the application of so-called lowest concentration of interest (LCI) values [105].…”

Effect of oxidising and reducing agents on the release of volatile organic compounds (VOCs) from strands made of Scots pine (Pinus sylvestris L.)

“…There is a countless number of publications covering the subject (e.g. Carlson et al 1995;Wolcott et al 1996;Wang and Gardner 1999;Makowski et al 2005;Makowski and Ohlmeyer 2006a, b). The emission from wood-based panels is, insofar, a complicated function of many factors and their reciprocal interaction.…”