Michael Altgen
Research Scientist
Biography
I am a wood material scientist working with different wood-based products. My main interest is the relationship between the chemical and structural characteristics of wood and their link to function and performance.
I obtained a doctoral degree in Wood Biology and Wood Technology from the University of Göttingen (Germany) in 2016. Since then, I had academic positions at Aalto University (Finland) and the University of Hamburg (Germany) before joining NIBIO in 2023.
Abstract
No abstract has been registered
Authors
Samuel L. Zelinka Samuel V. Glass Eleanor Q. D. Lazarcik Emil E. Thybring Michael Altgen Lauri Rautkari Simon Curling Jinzhen Cao Yujiao Wang Tina Künninger Gustav Nyström Christopher Huber Dreimol Ingo Burgert Mohd Khairun Anwar Uyup Tumirah Khadiran Mark G. Roper Darren P. Broom Matthew Schwarzkopf Arief Yudhanto Mohammad Subah Gilles Lubineau Maria Fredriksson Marcin Strojecki Wiesław Olek Jerzy Majka Nanna Bjerregaard Pedersen Daniel J. Burnett Armando R. Garcia Els Verdonck Frieder Dreisbach Louis Waguespack Jennifer Schott Luis G. Esteban Alberto Garcia-Iruela Thibaut Colinart Romain Rémond Brahim Mazian Patrick Perre Lukas Emmerich Ling LiAbstract
No abstract has been registered
Authors
Gry Alfredsen Lone Ross Michael Altgen Igor A. Yakovlev Anne-Cathrine Flyen Mari sand Austigaard Johan Mattsson Nanna Bjerregaard PedersenAbstract
No abstract has been registered
Authors
Gry Alfredsen Lone Ross Michael Altgen Igor A. Yakovlev Anne-Cathrine Flyen Mari sand Austigaard Johan Mattsson Nanna Bjerregaard PedersenAbstract
No abstract has been registered
Abstract
The dimensional stabilisation of wood using thermosetting resins relies on the resin uptake into the cell walls. This study tested if a conditioning step after the impregnation and before the final heat-curing enhances the cell wall uptake to improve dimensional stabilisation without increasing the chemical consumption. Small blocks of Scots pine sapwood were vacuum-impregnated with an aqueous melamine formaldehyde solution and conditioned at 33, 70, or 95 % RH for up to 1 week before drying and curing the blocks at 103 °C. However, the conditioning step decreased the cell wall bulking and the moisture exclusion effect compared to the immediate heat curing of the impregnated samples. Analyses of the resin-treated samples by scanning electron microscopy, IR spectroscopy and confocal Raman microspectroscopy provided evidence of wood hydrolysis and polycondensation of the resin within the cell lumen during the conditioning step. Hydrolysis and removal of wood constituents may have counterbalanced the cell wall bulking of the resin. Polycondensation of the resin in the lumen increased its molecule size, which could have hindered the cell wall diffusion of the resin.
Authors
Michael Altgen Michael Fröba Julius Gurr Andreas Krause Martin Ohlmeyer Uta Sazama Wim Willems Martin NopensAbstract
Water-sorption studies and certain organic chemistry reactions require water removal from cellulosic samples. This is hindered by the strong interaction of cellulosic materials with water, and it remains uncertain if a completely anhydrous state can be reached under common drying conditions. Here, different drying conditions were applied to wood and cellulose, and the residual moisture contents were quantified either gravimetrically or by coulometric Karl-Fischer titration. Vacuum-drying at 103 °C and ≤ 1 mbar for at least 360 min decreased the moisture content to ≤ 0.04%. However, in automated sorption balances, drying at atmospheric pressure under dry air or nitrogen flow left some samples with more than 1% moisture content. The residual moisture content obtained under dry gas flow was temperature dependent. Increasing the temperature up to 55 °C decreased the residual moisture content and cooling resulted in a moisture re-uptake, presumably due to small quantities of water vapor in the surrounding atmosphere. These effects must be considered in fundamental studies on water interactions of cellulosic materials.
Abstract
No abstract has been registered
Authors
Gry Alfredsen Lone Ross Michael Altgen Igor A. Yakovlev Anne-Cathrine Flyen Mari sand Austigaard Johan Mattsson Nanna Bjerregaard PedersenAbstract
No abstract has been registered