scholarly journals Hygromechanical mechanisms of wood cell wall revealed by molecular modeling and mixture rule analysis

2021 ◽  
Vol 7 (37) ◽  
Author(s):  
Chi Zhang ◽  
Mingyang Chen ◽  
Sinan Keten ◽  
Benoit Coasne ◽  
Dominique Derome ◽  
...  
Keyword(s):  
Cell Wall ◽  
Molecular Modeling ◽  
Wood Cell Wall ◽  
Mixture Rule ◽  
Rule Analysis

Acetyl Group Distribution in Acetylated Wood Investigated by Microautoradiography

Holzforschung ◽  
2001 ◽  
Vol 55 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Marie Rosenqvist
Keyword(s):  
Cell Wall ◽  
Weight Gain ◽  
Acetic Anhydride ◽  
Wood Cell Wall ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Accurate Information ◽  
Concentration Gradients ◽  
Good Opportunity ◽  
Acetyl Group

Summary Sapwood of Scots pine (Pinus silvestris L.) was acetylated with 14C- and 3H-labelled acetic anhydride. The distribution of acetyl groups was investigated with microautoradiography and microautoradiographs were evaluated with ESEM, Environmental Scanning Electron Microscopy. The investigation showed that the impregnation of wood with radioisotope-labelled substances provides a good opportunity to investigate the location of substances covalently bonded to the wood material. Introduced 14C-labelled acetyl groups show an even distribution in the wood cell wall, with no discernible concentration gradients at acetylation levels of about 5, 15 and 20% weight gain. 3H-labelled acetyl groups show an even distribution in the wood cell wall at 15 and 20% weight gain, with no discernible concentration gradients. At the 5% weight gain level, however, an uneven distribution of 3H-labelled acetyl groups over the cell wall is observed. Nevertheless, the unevenness is random and no concentration gradient is discernible at this level. 3H with a relatively high resolution, 0.5–1 μm, compared to 14C with a resolution of 2–5 μm, gives more accurate information about where exactly the acetyl groups are situated in the wood cell wall. Acetic anhydride was evenly distributed when a full impregnation procedure was used. The chemical and physical properties of acetic anhydride allow a uniform penetration into the pine cell wall and a complete acetylation takes place when the specimens are heated.

scholarly journals Enhancement of the physical and mechanical properties of wood using a novel organo-montmorillonite/hyperbranched polyacrylate emulsion

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jianfeng Xu ◽  
Xiaoyan Li ◽  
Ling Long ◽  
Ru Liu
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Pinus Radiata ◽  
Wood Sample ◽  
Wood Cell Wall ◽  
Physical And Mechanical Properties ◽  
Radiata Pine ◽  
Compact Structure ◽  
Populus Cathayana ◽  
Modified Wood

AbstractIn this work, a novel waterborne hyperbranched polyacrylate (HBPA) dispersed organo-montmorillonite (OMMT) emulsion was synthesized and used for the treatment of wood in a vacuum environment in order to enhance the physical and mechanical properties of the wood. The sapwood of Cathay poplar (Populus cathayana Rehd.) and Radiata pine (Pinus radiata D.Don) were used as the samples for experimentation. The results showed that the physical and mechanical properties of the wood improved significantly due to the successful penetration of the OMMT and HBPA into the wood cell wall. From it was also observed that OMET completely exfoliated from the HBPA matrix and formed a hydrophobic film covering on the inside walls of the cell lumen. Further, it was observed that the poplar sample displayed better mechanical properties than the pine sample because the pine has a more compact structure when compared to poplar and contains rosin. Furthermore, it was also observed that the mechanical properties of the modified wood sample gradually improved with an increase in the concentration of the emulsion. However, excessive concentration (>4 wt%) did not lead to further improvement.

scholarly journals Microstructure of thermally modified radiata pine wood

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 1523-1533
Author(s):  
José Luis Cabezas-Romero ◽  
Linette Salvo-Sepúlveda ◽  
Helga Contreras-Moraga ◽  
Natalia Pérez-Peña ◽  
Víctor Sepúlveda-Villarroel ◽  
...  
Keyword(s):  
Cell Wall ◽  
Wood Cell Wall ◽  
Morphological Changes ◽  
Untreated Wood ◽  
Radiata Pine ◽  
Treatment Temperature ◽  
Thermal Modification ◽  
Modification Process ◽  
Potential Alternative ◽  
Two Temperatures

The thermal modification of wood is a potential alternative method for improving wood dimensional stability and increasing the resistance of wood to decay. However, during thermal modification, morphological changes occur within the microstructure of the cell, and these confer different properties to the wood. This study investigated the effects of the thermal modification process on the microstructure of radiata pine juvenile wood. Therefore, anatomical measurements were performed via optical microscopy in selected earlywood and latewood samples after each treatment, and the results were compared to untreated wood samples. In this study, two temperatures (190 °C and 210 °C) were considered for the thermal modification process. The results showed that the level of temperature of modification affected to microstructure of cell wall. The cell wall thickness decreased as treatment temperature increased, whereas the average lumen diameter increased slightly as temperature increased. Thermally modified radiata pine showed signs of damage (cracks, broken cells and deformations in the wood cell wall). The proportion of destroyed area increased as temperature increased, and significant differences were evident for the thermal treatment at 210 °C.

scholarly journals Mechanical Function of Lignin and Hemicelluloses in Wood Cell Wall Revealed with Microtension of Single Wood Fiber

BioResources ◽  
2013 ◽  
Vol 8 (2) ◽  
Author(s):  
Shuang-Yan Zhang ◽  
Chuan-Gui Wang ◽  
Ben-Hua Fei ◽  
Yan Yu ◽  
Hai-Tao Cheng ◽  
...  
Keyword(s):  
Cell Wall ◽  
Wood Cell Wall ◽  
Wood Fiber ◽  
Mechanical Function

Effect of different coupling agents on the thermal, mechanical and biological behavior of vinyl acetate-wood polymer composite

Holzforschung ◽  
2019 ◽  
Vol 73 (10) ◽  
pp. 967-973 ◽  
Author(s):  
Maryam Ghorbani ◽  
Zahra Asghari Aghmashhadi ◽  
Seyed Mojtaba Amininasab ◽  
Raoufeh Abedini
Keyword(s):  
Cell Wall ◽  
Vinyl Acetate ◽  
Cell Walls ◽  
Populus Deltoides ◽  
Wood Cell Wall ◽  
Decay Resistance ◽  
Biological Behavior ◽  
Second Step ◽  
Wood Polymer ◽  
Modify Wood

AbstractPoplar wood (Populus deltoidesBartr.) was modified by a combined two-step treatment with different chemicals to improve its properties. Maleic anhydride (MAN), 3-(trimethoxysilyl) propyl methacrylate (TMPS) and glycidyl methacrylate (GMA) were first employed to modify wood cell wall resulting in WMAN, WTMPSand WGMA. Then, in a second step, the vinyl acetate (VA) monomer was let to polymerize within the cell lumina resulting in WPCMAN/VA, WPCTMPS/VAand WPCGMA/VA(WPCs). Field emission scanning electron microscopy (FESEM) observations confirmed the bulking of modified cell walls. The thermal stability, mechanical properties and decay resistance of WPCs were remarkably improved compared to unmodified wood in the order WPCGMA/VA >  WPCTMPS/VA > WPCMAN/VA. WPCMAN/VAdisplayed a significant decay resistance increment, despite lower retention and reactivity than the WPCTMPS/VA, which is probably due to a better penetration into the cell wall and the higher degree of chemical modification of the wood components.

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