Emission of volatile organic compounds (VOC) from wood during processing to pelletssignificance of wood extractives. Cellulose, hemicelluloses and lignin are the main components of the cell wall in wood. Moreover, wood contains different amounts of extractives, depending on the wood species. Extractives in softwoods play an important role during processing of wood to different wood products. This work studies the influence of storage on the change of extractives as well as on the emission of monoterpenes (primary emission) and aliphatic aldehydes, as degradation products of fats and fatty acids (secondary emission). In case of pine wood storage for 2 days at 80uC proved to be more efficient in the reduction of emissions of terpenes and aldehydes than 4 weeks at 40uC. Quantitative differences between pine (Pinus sylvestris) and spruce (Picea abies) wood chips in the emission were evaluated and discussed. Pinewood emits about 10 times higher amounts of terpenes and aldehydes than spruce wood. The results indicate that the intense of change in primary and secondary emissions due to storage depends on the wood species as well as on the boundary conditions under which storage is carried out. In general, storage at high temperature (80uC) is much more effective than at low temperature (40uC). The results also reveal that removal of wood extractives from pine wood by extraction with ethanol-cyclohexane or treatment with sodium hydroxide decreases the emission of primary and secondary volatile organic compounds drastically. Nevertheless, after such treatments minute amounts of volatile organic compounds are still detectable.

Earlier kinetic investigations on the anionic polymerization of methyl methacrylate (MMA) in tetrahydrofuran (THF) showed that under appropriate conditions the reaction can be regarded to proceed in an ideal manner1-4). The Arrhenius plots of the rate constants for the propagation reaction of ion pairs with both Na+ and Cs+ as counterions exhibit straight lines which can be regarded to be identical within the limits of experimental error; thus no evidence for the existence of more than one kind of ion pair is given4). The kinetically undifferentiated behaviour of the two counterions, which is in strong contrast to their behaviour in the polymerization of styrene5x6), was explained assuming the propagating species to be contact ion pairs intramolecularly "solvated" by the penultimate or antepenultimate ester group of its own polymer chain (A, B). A B M+:Na* or Cs' Solvation complex B facilitates chain termination occurring at higher temperatures which partly seems to be due to a reaction of the carbanion with the antepenultimate ester group, resulting in a cyclic 8-ketoester end group2v3).A solvent with a higher solvating power, such as 1,2-dimethoxyethane (DME), should result in a lower stability of the intramolecular complex. With sodium as the counterion part of the active centres were expected to exist in the form of externally a) Present address: Lehrstuhl fur Makromolekulare Chemie, Universitat Bayreuth, D-8580 Bayreuth.

Residues of Bagasse (Saccharum officinarum L.), canola (Brassica napus L.) and hemp (Cannabis sativa L.) as well as industrial wood chips in various proportions from 0-100% were used as raw materials for the main component of the middle layer in urea formaldehyde bonded particle boards.The results reveal that most of the investigated mechanical-technological properties of the boards achieved the requirements of EN 312-2 (2003). Only increasing the percentage of canola chips usage in the middle layer to more than 30% negatively affect the internal bond (IB) properties. Comparing the water absorption (WA) and thickness swelling (TS) values, the boards containing up to 50% bagasse and hemp reach similar values to the ones of the reference boards, while increasing the amount of canola leads to more and more disadvantageous WA and TS.In summary, the results reveal that agri-fibers can be used for making composite panels conforming to the standards (EN 312-2 2003). One possible application for these panels could be the production of furniture. Einsatz von Ernterückständen von Bagasse, Rapsstroh und Hanfschäben bei der Herstellung von dreischichtigen SpanplattenThis article is dedicated to Gerd Wegener on the occasion of his retirement as professor at the Technische Universität München.

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Thermal modification of wood (ash, beech, spruce) leads to a remarkable decrease in the Water Retention Value (WRV). In case of beech wood the WRV-value decreased after immersion in water for 72 h from 55.5% to 40.5% (about 27%) and in case of spruce wood from 49.3% to 34.5% (about 30%). The decrease in the WRV of ash wood was relatively low (about 19%). The WRV-method seems to be useful to follow up the process of thermal modification of wood. Ziel der UntersuchungenDie Modifizierung von Holz durch thermische Behandlung, die das Holz chemisch (Fengel 1966a(Fengel , 1966bWindeisen et al. 2007) und physikalisch (Kollmann und Schneider 1963)

In this study, the extractive contents and the storage-induced emissions from chips of Salix alba, Betula pendula, Populus tremula, and Alnus glutinosa are compared with emissions from Pinus sylvestris chips. Soxhlet extraction was performed, and carbon monoxide (CO) and O 2 concentration in the gas phase as well as gas chromatography-mass spectrometry analysis of volatile organic compounds were analyzed. Pinus sylvestris showed the highest extractive content in the petrol ether fraction and emitted CO in the highest concentration. Salix alba, B. pendula, P. tremula, and A. glutinosa have lower extractive contents in the petrol ether fraction and the CO concentrations decreased in the headspace accordingly. The emission of aldehydes was lower in the case of woods with lower petrol ether contents (P. sylvestris, S. alba, and B. pendula), but the situation was not as clear for P. tremula and A. glutinosa. The origin of CO and aldehyde emissions is discussed in view of the possible oxidative degradation processes of lipids and terpenes.

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