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Yellow poplar (Liriodendron tulipifera L.) wood flour was chemically modified with acetic anhydride at varying times and initial moisture contents at a constant temperature. All samples exhibited increasing weight gains in the range of 5–16% with increasing reaction or treatment time. The acetylated poplar wood flour was characterized by means of Fourier transform infrared spectroscopy and near infrared (NIR) spectroscopy. Principal component analysis performed on the spectral data revealed clusters according to the esterification level. Partial least squares regression models developed from NIR data were able to predict the weight gain and the percentage of reacted OH groups. The correlations show that there is a direct and linear relationship between the spectra and the weight percentage gain and, therefore, the degree of acetylation.

In this work, near infrared (NIR) and pyrolysis-molecular beam mass spectra (MBMS) of loblolly pine (Pinus taeda) were studied by means of generalized two-dimensional correlation spectroscopy in order to assign specific contributions of cellulose in the two spectral domains. Homo- and hetero-correlation techniques were employed to analyze the concentration-dependent spectral variations of cellulose. Specific bands of cellulose were assigned in the NIR and MBMS spectra, and moreover two masses m/z at 114 and 173, commonly assigned to cellulose fragments, were found to not originate from the pyrolysis of cellulose.

The time domain of 1H NMR spectroscopy allows straightforward editing of the T 2 relaxation profiles in maritime pine wood. A new method from the Carr-Purcell-Meiboom-Gill sequence is proposed to measure the amount and distribution of water in wood, as well as the location of major dissolved organic materials. A general calibration model giving reliable and precise identification of these parameters is described. The method presented for editing T 2 relaxation profiles (obtained by the Contin program) may be helpful in solving practical drying and gluing problems in the wood industry. It can be used for monitoring chemical modifications of wood fibers involved in the design of wood composite materials.

SummaryThe low field1H NMR relaxometry technique has been shown to be effective in determining the qualitative and quantitative moisture content and the water state distribution in maritime pine wood (Pinus pinasterAit). Further investigations on extractive materials in resin-rich samples evinced the presence of oleoresin components, which may disturb adhesion on pine wood boards.

White oak is commonly used for cooperage and the heartwood extractives are important for this application because of their impact on the flavor and color of wine and spirits aged in white oak barrels. White oak extractives comprise a complex mixture of compounds and the composition of the mixture can change within trees over time. The ability to monitor the extractives component of white oak heartwood could be helpful for assessments of barrels and their contents. Wood from five American white oak stave logs was sampled. NIR-based models could provide reasonable predictions of the concentration of individual extractives components. However, these extractives were highly correlated to one another and to radial location suggesting that segregation of white oak material based on distance from the pith could be an efficient method for selecting samples that are relatively rich in flavor-associated chemicals. The relatively poor near infrared-based prediction ability for total extractives content could be due to age-related changes in the composition of the mixture of extractives across the radius.