Mechanical stability of superhydrophobic epoxy/silica coating for better water resistance of wood

Holzforschung ◽  
2015 ◽  
Vol 69 (3) ◽  
pp. 367-374 ◽  
Author(s):  
Feng Liu ◽  
Zhengxin Gao ◽  
Deli Zang ◽  
Chengyu Wang ◽  
Jian Li

Abstract A three-step procedure has been developed for superhydrophobic coating on wood based on epoxy/silica materials in combination with hydrophobization. First, the epoxy resin is adhered to wood by immersing the samples into an epoxy resin acetone solution, then amino-functionalized silica particles are anchored by the epoxide groups, and finally, the created surface is modified by octadecyltrichlorosilane (OTS). The superhydrophobic surface not only is water repellent, as shown by the contact angle (CA) tests, but also decreases essentially the wood’s water absorption as determined by a 120-day water immersion test. The good mechanical stability of the coating was confirmed by a sand collision method.

2008 ◽  
Vol 368-372 ◽  
pp. 352-354 ◽  
Author(s):  
Lin Zhang ◽  
Hiroshi Yamada ◽  
Yusuke Imai ◽  
Chao Nan Xu

We successfully developed a novel elasticoluminescent (EML) material with water resistance, CaAl2Si2O8:Eu2+ (CAS). The crystal structure, photoluminescence (PL) and EML properties were characterized for both CAS and the typical EML material SrAl2O4:Eu2+(SAO). Contrary to SAO, CAS showed superior water resistance property. No changes were found in the XRD patterns, and the PL, EML intensities, during the whole examination of water immersion test.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 251
Author(s):  
Jijia Zhang ◽  
Jihu Wang ◽  
Shaoguo Wen ◽  
Siwei Li ◽  
Yabo Chen ◽  
...  

In this paper, an environmentally friendly waterborne polyurea (WPUA) emulsion and its corresponding coating were prepared, which was characterized by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). To improve the performance of the coating, we doped sulfonated graphene (SG) into WPUA to prepare composite coating (SG/WPUA). SG can be uniformly dispersed in WPUA emulsion and is stable for a long time (28 days) without delamination. The water resistance of the composite coating with 0.3 wt.% SG nanofiller was improved; the water contact angle (WCA) result was SG/WPUA (89°) > WPUA (48.5°), and water absorption result was SG/WPUA (2.90%) < WPUA (9.98%). After water immersion treatment, SEM observation revealed that the SG/WPUA film only generated enlarged microcracks (100 nm) instead of holes (150–400 nm, WPUA film). Polarization curves and electrochemical impedance spectroscopy (EIS) tests show that SG nanosheets with low doping content (0.3 wt.%) are more conducive to the corrosion resistance of WPUA coatings, and the model was established to explain the mechanism.


2016 ◽  
Vol 844 ◽  
pp. 153-156 ◽  
Author(s):  
Mateusz Fijalkowski ◽  
Kinga Adach ◽  
Aleš Petráň ◽  
Dora Kroisová

Rice husks (RH) are characterized by a high content of silicon dioxide up to 23 wt. %. Silica in the form of nanoparticles creates surface layers formed in various plant parts which ensure protective properties and mechanical stability. These nanoparticles with a dimension in the range of tens of nanometers, are formed during biochemical processes and photosynthesis. Individual nanoparticles are interconnected between themselves and between layers with organic phase via cellulose fibres. Accompanying ions mainly potassium, calcium, sodium, magnesium and aluminium extremely important for plant growth have also been identified in rice husks. In this research paper we investigated mechanical properties of composite epoxy resin material, which was composed of ChS Epoxy 520 filled with silica obtained from rice husks. Nanoparticles of silicon dioxide with the size in dozen of nanometers were prepared by calcination of raw plant parts. We found that the 0.1 phr of filling (0.01 g of filler + 10 g of epoxy) demonstrated a significant increase of wear resistance and decrease of coefficient of friction. An excellent adhesion between epoxy resin and silica nanoparticles was also observed. The silicon dioxide in epoxy resin plays the role of the hard phase, which transfers part of the load and protects the surface of polymer against wear. The presence of this filler does not change the mechanical properties of the original resin.


2011 ◽  
Vol 236-238 ◽  
pp. 1199-1202
Author(s):  
Shu Fang Zhou ◽  
Chuan Shan Zhao ◽  
Jing Jing Wang

In this paper, a kind of sizing synergist,AKD,cationic rosin(CRS) and oil resistance agent were mixed in different proportions, we make it as a kind of new water repellent agent ,and for internal sizing. The best dosage and the composite ratio of the synergist, AKD, cationic rosin and oil resistance agent was discussed mainly in this experiment. And then the copy paper were tested of the substanceweight and contact angle, and compared with the water resistance when the domestic water repellent agent or AKD was added alone. Conclusions of this experiment are following: the optimal conditions were that the mass ratio of AKD and CRS is 6:4, the additive level of AKD and the cationic rosin is 6% (based on dry weight of pulp), the quantity of the sizing synergist is 0.5% , and no oil resistance agent was added, the effect of water resistance is best.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9584-9595
Author(s):  
Mustafa Zor

The friction welding method has been an effective criterion in determining the mechanical performance of wood joints in wood industry applications compared to traditional methods. Although it is used in structural applications, joints from linear vibration are quite sensitive to water. In this study, the water resistance of the heat-treated woods, iroko (Chlorophora excelsa), ash (Fraxinus excelsior L.), tulip wood (Liriodendron tulipifera) and ayous (Triplochiton scleroxylon), were investigated by friction linear welding. The weld line density profiles were examined. The resistance of heat-treated welded wood joints to water remarkably decreased compared to the control sample, depending on water immersion time. The highest shear strength loss was found in tulip wood (60% to 65%) and the lowest shear strength loss was found in ash wood (3%) for the heat-treated group and in Iroko wood (17%) for the control. The heat-treated samples increased in density with welding but had a slightly lower density than the control group. According to the TGA results, it was found that the thermal degradation of untreated welded woods was lower than that of heat-treated welded woods. This difference could be due to the chemical constituents of hardwood and tropical wood. X-ray computed tomography (CT-scanning) is feasible and usable for welding line density change.


2021 ◽  
pp. 50-58
Author(s):  
V.A. Kuznetsova ◽  
◽  
V.G. Zheleznyak ◽  
S.L. Lonskii ◽  
N.A. Kovrizhkina ◽  
...  

Adhesion, physicomechanical properties, and also kinetics of water absorption of priming coatings on basis the E-41 epoxy resin modified by liquid Thiokol 1 and by Laproxide AF, and also their phase structure are investigated. As hardeners of primer compositions organic silicon ammine ASOT-2 and low-molecular polyamide PO-200 has been used. It is shown that use of the reactive modifier Laproxide AF and hardener ASOT-2 in the epoxy and thiokol film-formers allows to receive priming coating with uniform finely divided phase structure with low porosity and high water resistance.


2020 ◽  
Vol 12 (15) ◽  
pp. 5876
Author(s):  
Chang-Ho Choi ◽  
Yeongwon Kwak ◽  
Min Kyung Kim ◽  
Dong Gun Kim

Advances in harmful organism management are highly demanding due to the toxicity of conventional coating approaches. Exploiting biomimetic superhydrophobicity could be a promising alternative on account of its cost-effectiveness and eco-friendliness. Here, we introduce a facile method to fabricate a robust superhydrophobic coating on a fabric substrate. This is achieved by sequentially spraying TiO2-epoxy resin nanocomposite material and fluorocarbon-silane modified SiO2 nanoparticles (FC-silane SiO2 NPs). The superhydrophobicity is attributed to the nanoparticles constituting a micro/nano hierarchical structure and the fluorocarbon of the modified SiO2 NPs lowering the surface energy. The epoxy resin embedded in the coating layer plays an important role in improving the robustness. The robustness of the superhydrophobic surface is demonstrated by measuring the water slide angle of surfaces that are subject to salty water at 500 rpm stirring condition for up to 13 days. This study focuses on ensuring the superhydrophobicity and robustness of the coating surface, which is preliminary work for the practical management of macrofoulers. Based on this work, we will perform practical harmful organism management in seawater as a second research subject.


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