Study of Puffing Cell Walls

2010 ◽  
Vol 113-116 ◽  
pp. 239-242
Author(s):  
Jian Qiu ◽  
Jean Ran Gao ◽  
Mon Lin Kuo ◽  
Jian Li

Since wood is porous it also is a good heat and sound insulating material. Puffing the cell wall may lose certain level of mechanical properties but would increase its insulation properties. In this study, Trema orientalis wood was first treated with nitric acid aqueous solution to damage the S3 layer of cell walls, followed by puffing the cell wall inward with saturated urea and ZnCl2 solutions. Results indicated that treating Trema orientalis with 10% nitric acid at 100 oC for 20 minute damaged the S3 layer of cell walls, and the subsequent treatment with urea and ZnCl2 saturated solutions caused the fiber tracheid walls to swell up to 76%. Then, the swollen material was dried with critical CO2 fluid to obtain puffed wood. SEM examinations of nitric acid-treated samples showed that lignin were removed from the S3 layer surfaces and S3 mirofibrils were ruptured causing the entire secondary walls to swell inward.

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.


Fibers ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 6 ◽  
Author(s):  
Camille Goudenhooft ◽  
David Siniscalco ◽  
Olivier Arnould ◽  
Alain Bourmaud ◽  
Olivier Sire ◽  
...  

2016 ◽  
Vol 54 (2) ◽  
pp. 182-187
Author(s):  
Daisuke Watanabe ◽  
Yoichi Wada ◽  
Akira Sasahira ◽  
Masashi Itori ◽  
Tetsunari Ebina

Vestnik MGSU ◽  
2017 ◽  
pp. 642-646
Author(s):  
Natalia Shamilievna Lebedeva ◽  
Evgeniy Gennadievich Nedayvodin

Obtained building material based on magnesia binder with different content of peat (0 to 90 %), on a specially developed technique. As a binder used PMK 87, for mixing mixtures used aqueous solution of magnesium chloride and peat from the Ivanovo region. It were determined such physical and physico-mechanical properties of the investigated material as the compressive strength and the density. The strength characteristics of silicate bricks, ceramic bricks and the investigated material based on magnesia binder and peat was analyzed and compared. It is established that the samples of construction material with content of peat not exceeding 40 wt.% can be attributed to the materials of structural purpose by its compressive strength. Samples of the material with content of the peat 40% have a density 943,75 kg/m3, that provides good heat and sound insulation properties. It is revealed that the solution of the raw material mixture of magnesia binder, peat, the solution of bischofite is optimized to place, and the material gets at least 85% of its strength during 30 days.


Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 646 ◽  
Author(s):  
Wang ◽  
Chen ◽  
Xie ◽  
Cai ◽  
Yuan ◽  
...  

The local chemistry and mechanics of the control and phenol formaldehyde (PF) resin modified wood cell walls were analyzed to illustrate the modification mechanism of wood. Masson pine (Pinus massoniana Lamb.) is most widely distributed in the subtropical regions of China. However, the dimensional instability and low strength of the wood limits its use. Thus, the wood was modified by PF resin at concentrations of 15%, 20%, 25%, and 30%, respectively. The density, surface morphology, chemical structure, cell wall mechanics, shrinking and swelling properties, and macro-mechanical properties of Masson pine wood were analyzed to evaluate the modification effectiveness. The morphology and Raman spectra changes indicated that PF resin not only filled in the cell lumens, but also penetrated into cell walls and interacted with cell wall polymers. The filling and diffusing of resin in wood resulted in improved dimensional stability, such as lower swelling and shrinking coefficients, an increase in the elastic modulus (Er) and hardness (H) of wood cell walls, the hardness of the transverse section and compressive strength of the wood. Both the dimensional stability and mechanical properties improved as the PF concentration increased to 20%; that is, a PF concentration of 20% may be preferred to modify Masson pine wood.


Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 449 ◽  
Author(s):  
Yan Wu ◽  
Yingchun Sun ◽  
Feng Yang ◽  
Haiqiao Zhang ◽  
Yajing Wang

The waterborne coating uses water as its solvent, which will partially dissolve wood extractives when it is applied to wood surfaces. This influences both the coating curing process and the mechanical properties of the cured coating. To investigate these influences, the mechanical properties of waterborne polyacrylic coating on control and extractive-free wood surfaces were investigated by nanoindentation. Reductions to elastic modulus (Er) and hardness (H) of the coating layer was observed in the wood cell walls adjacent to or away from coating layers. Extraction treatment resulted in significant decrease of the Er and H of the coating layer on extractive-free wood surface comparing with control wood, but the values slightly increased for extractive-free wood cell walls compared to a control. Er and H of coating in wood cell lumen were higher than the average value of coating layer on wood surface in both the control and extractive-free wood. The Er of wood cell wall without coating filled in lumen was significantly higher than those of filling with coating. However, there was no distinct difference of H. The Er and H of CCML in extractive-free wood were 15% and 6% lower than those in control ones, respectively.


2020 ◽  
Vol 59 (16) ◽  
pp. 11459-11468 ◽  
Author(s):  
Gaël Loubert ◽  
Natacha Henry ◽  
Christophe Volkringer ◽  
Sylvain Duval ◽  
Christelle Tamain ◽  
...  

Holzforschung ◽  
2002 ◽  
Vol 56 (4) ◽  
pp. 395-401 ◽  
Author(s):  
W. Gindl

Summary Cell-wall lignin content and composition, as well as microfibril angle of normal and compression wood samples were determined prior to mechanical testing in compression parallel to the grain. No effect of increased lignin content on the Young's modulus in compression wood was discernible because of the dominating influence of microfibril angle. In contrast, compressive strength of compression wood was not negatively affected by the high microfibril angle. It is proposed that the observed high lignification in compression wood increases the resistance of the cell walls to compression failure. An increased percentage of p-hydroxyphenylpropane units observed in compression wood lignin may also contribute to the comparably high compressive strength of compression wood.


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