scholarly journals Synthesis and properties of nanosized ZnO/wood composite

2021 ◽  
Vol 23 (4) ◽  
pp. 578-584
Author(s):  
Elena V. Tomina ◽  
Anna A. Pavlenko ◽  
Aleksandr I. Dmitrenkov ◽  
Sofiya A. Neminushchaya
Keyword(s):  
Sol Gel ◽  
Physical And Mechanical Properties ◽  
Silver Birch ◽  
Zinc Hydroxide ◽  
Birch Wood ◽  
Wood Material ◽  
Natural Wood ◽  
20 Nm ◽  
Nanosized Zno ◽  
Contact Angle Of Wetting

The aim of the study was to synthesise a ZnO/silver birch wood (Bétula péndula) nanocomposite and evaluate its physical and mechanical properties in comparison with an unmodified natural polymer.Using the sol-gel method, we synthesised almost spherical impurity-free zinc oxide nanoparticles with a predominant particle size of about 20 nm. Amorphous hydrated Zn(OH)2 was impregnated into the wood material at the gel formation stage. It resulted in the reaction of zinc hydroxide decomposition with the formation of ZnO nanoparticles in the wood as a nanoreactor.The hydrophobic properties of the surface of ZnO/silver birch wood nanocomposite improved significantly (the contact angle of wetting doubled). Its moisture and water resistance decreased (2-5 times and 30%, respectively). The nanocomposite also showed less swelling in the radial (8-10 times) and tangential (2.6-10 times) directions in comparison with natural wood.

scholarly journals THE USE OF NANOSCALE ZINC OXIDE IN WOOD-BASED COMPOSITIONS

2021 ◽  
Author(s):  
S. Neminushchaya ◽  
E. Tomina ◽  
A. Dmitrenkov
Keyword(s):  
Zinc Oxide ◽  
Vegetable Oil ◽  
Zinc Oxide Nanoparticles ◽  
Sol Gel ◽  
Environmental Safety ◽  
Oxide Nanoparticles ◽  
Natural Wood ◽  
Oxide Particles ◽  
Used Vegetable Oil ◽  
20 Nm

The aim of this work was to study compositions based on vegetable oil waste and nanoscale zinc oxide particles for processing natural wood. The sol-gel method was used for the synthesis of zinc oxide nanoparticles. The synthesized zinc oxide nanoparticles did not contain impurities and had a shape close to spherical, and their size did not exceed 20 nm. We used freshly prepared suspensions of zinc oxide nanoparticles in used vegetable oil with their content in the amount of 0.1, 0.5 and 1.0 wt. parts per 100 parts of oil. The wood was treated by hot-cold impregnation. The tests were carried out on samples of birch and pine wood of standard sizes. In the modified samples, the wetting angle, moisture and water absorption, as well as their swelling were determined. It is shown that the use of zinc oxide nanoparticles in compositions based on vegetable oil waste can significantly reduce the moisture and water resistance of wood and reduce its swelling. The optimal dosages of the nanopowder introduced into the used vegetable oil and the conditions of impregnation were selected. The compositions used on the basis of vegetable oil waste are characterized by environmental safety, and the resulting wood samples had an improved appearance.

scholarly journals Eco-Friendly, High-Density Fiberboards Bonded with Urea-Formaldehyde and Ammonium Lignosulfonate

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 220
Author(s):  
Petar Antov ◽  
Viktor Savov ◽  
Ľuboš Krišťák ◽  
Roman Réh ◽  
George I. Mantanis
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
High Density ◽  
Thickness Swelling ◽  
Formaldehyde Content ◽  
Uf Resin ◽  
Natural Wood ◽  
European Standards

The potential of producing eco-friendly, formaldehyde-free, high-density fiberboard (HDF) panels from hardwood fibers bonded with urea-formaldehyde (UF) resin and a novel ammonium lignosulfonate (ALS) is investigated in this paper. HDF panels were fabricated in the laboratory by applying a very low UF gluing factor (3%) and ALS content varying from 6% to 10% (based on the dry fibers). The physical and mechanical properties of the fiberboards, such as water absorption (WA), thickness swelling (TS), modulus of elasticity (MOE), bending strength (MOR), internal bond strength (IB), as well as formaldehyde content, were determined in accordance with the corresponding European standards. Overall, the HDF panels exhibited very satisfactory physical and mechanical properties, fully complying with the standard requirements of HDF for use in load-bearing applications in humid conditions. Markedly, the formaldehyde content of the laboratory fabricated panels was extremely low, ranging between 0.7–1.0 mg/100 g, which is, in fact, equivalent to the formaldehyde release of natural wood.

Natural Rubber Reinforced with Silica Nanoparticles Extracted from Jasmine and Riceberry Rice Husk Ashes

2018 ◽  
Vol 936 ◽  
pp. 31-36 ◽  
Author(s):  
Wichudaporn Seangyen ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
Peerapan Dittanet
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Silica Nanoparticles ◽  
Rice Husk ◽  
Sol Gel ◽  
Rubber Matrix ◽  
Reinforcing Fillers ◽  
Rubber Nanocomposites ◽  
Jasmine Rice ◽  
20 Nm

Silica nanoparticles were synthesized by rice husk ash (RHA) produced from jasmine rice husk and riceberry rice husk via sol-gel method for the use as reinforcing fillers in natural rubber (NR). The obtained silica nanoparticles are spherical in shape and the particle sizes were observed to be in the 10-20 nm range with uniformly size distribution. The surface of silica nanoparticles was treated with a silane coupling agent confirmed by FTIR. The treated silica nanoparticles were then incorporated into NR and vulcanized with electron beam irradiation. The rubber nanocomposites with silica nanoparticles, produced from jasmine rice husk and riceberry rice husk, resulted in higher mechanical properties (tensile strength and modulus) than neat rubber vulcanizate. The modified rubber vulcanizates revealed rougher surface with tear lines as compared to the neat rubber vulcanizates, indicating the improved strength. Interestingly, the rubber nanocomposites with silica nanoparticles from jasmine rice husk showed higher tensile strength and modulus than silica nanoparticles produced from riceberry rice husk. The micrographs indicated better dispersion of NR composites with jasmine rice husk which leads to a strong interaction between silica nanoparticles and rubber matrix, thereby improving the strength.

Ferromagnetism, Raman Spectra and Photoluminescence of Sn0.91Co0.05Ce0.04O2 and Sn0.91Fe0.05Ce0.04O2 Nanorods

2012 ◽  
Vol 488-489 ◽  
pp. 226-229
Author(s):  
Jasneet Kaur ◽  
R.K. Kotnala ◽  
Vinay Gupta ◽  
Kuldeep Chand Verma
Keyword(s):  
Raman Spectroscopy ◽  
Magnetic Measurements ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Stoichiometric Ratio ◽  
Chemical Route ◽  
Structural Modifications ◽  
Co Doping ◽  
Transmission Electron ◽  
20 Nm

In the present work, we have fabricated Sn0.91Co0.05Ce0.04O2 (SCC54) and Sn0.91Fe0.05Ce0.04O2 (SFC54) nanorods by a chemical route similar to sol-gel method. X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, photoluminescence (PL) and magnetic measurements are used to characterize these nanorods. XRD pattern shows the polycrystalline nature of rods and TEM confirms that the diameter of rods lie in the range of 15-20 nm and length 100-200 nm. It is observed that on Ce3+ co-doping, nanoparticles assembled themselves into rod like structures. The SCC54 and SFC54 specimens exhibit room temperature ferromagnetism. Their saturated magnetic moment and phase transition temperature is sensitive to their size and stoichiometric ratio. Raman spectroscopy shows an intensity loss of classical cassiterite SnO2 vibration lines, which is indication of significant structural modifications like crystallinity and nano metric size effects on the vibrational properties. From PL spectra, an intense blue luminescence centred at a wavelength of 532 nm is observed in the prepared SnO2 nanostructures, attributed to oxygen-related defects, introduced during the growth process.

TiO2 and ZnO Water Sol Preparation by Sol–Gel Method and Application on Polyester Fabric of Antistatic Finishing

2011 ◽  
Vol 331 ◽  
pp. 270-274 ◽  
Author(s):  
Yan Yan Chu ◽  
Qing Wang ◽  
Shi Zhong Cui
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Sol Gel ◽  
Physical And Mechanical Properties ◽  
Polyester Fabric ◽  
Pure Tio2 ◽  
The Other ◽  
Baking Process ◽  
Result Show ◽  
The Stability

Abstract：Pure TiO2 water sol, pure ZnO water sol and three compound TiO2/ZnO water sols are prepared under low temperature. Then the padding and baking process is used to put the functional sol liquid on the fabric. SEM is use to analyzed the change of surface feature and the result show that all of the water sol except pure ZnO water sol liquid formed a thin film on the fiber The stability of pure ZnO water sol is the best one and the pure TiO2 water sol is the worst one at temperature of 15°C. The compound water sols stabilities are between these two water sols and with the more amount of ZnO, the stability last longer. Both mole of TiO2 and ZnO with the rate of 5 to 5 and 7 to 3 display the best antistatic behavior, but the washing fastnesses are not good. After treatment, the moisture regain displays most dramatically changes; the next one is whiteness of fabric, but the other physical and mechanical properties have a little change.

Synthesis and Thermal Stability of Nontransformable Tetragonal (ZrO2)0.96(REO1.5)0.04 (Re=Sc3+, Y3+) Nanocrystals

2013 ◽  
Vol 334-335 ◽  
pp. 60-64 ◽  
Author(s):  
Mohammad Reza Loghman-Estark ◽  
Reza Shoja Razavi ◽  
Hossein Edris
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Scanning Electron

Scandia, yttria doped zirconia ((ZrO2)0.96(REO1.5)0.04(RE=Sc3+, Y3+)) nanoparticles were prepared by the modified sol-gel method. The microstructure of the products was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Thermal stabillity of SYSZ nanocrystals were also investigated. The SYSZ nanocrystals synthesized with EGM:Zr+4mole ratio 4:1, calcined at 700°C, have average diameter of ~20 nm.

scholarly journals Structure and Properties of Resorcinol-Formaldehyde Gels

1989 ◽  
Vol 177 ◽  
Author(s):  
Stephan A. Letts ◽  
Steven R. Buckley ◽  
Fung-Ming Kong ◽  
Edward F. Lindsay ◽  
Margaret L Sattler
Keyword(s):  
Catalyst Concentration ◽  
Sol Gel ◽  
Freeze Fracture ◽  
Effect Of Temperature ◽  
Condensation Polymerization ◽  
Resorcinol Formaldehyde ◽  
Solids Concentration ◽  
Rate Of Increase ◽  
Sol Gel Transition ◽  
20 Nm

ABSTRACTThe condensation polymerization of resorcinol and formaldehyde catalized by sodium carbonate produces a sol that aggregates to form a gel. Using viscometry the effect of temperature and catalyst concentration on the sol-gel transition was investigated. At a solids concentration of 3%, gelation occurred in 1500 minutes. The rate of increase in viscosity was a function of both catalyst concentration and temperature. The structure of the gels was studied by freeze-fracture TEM. In the sol phase the RF solutions contain particles of 5 to 20 nm diameter. After gelation the particles form a crosslinked network with a pore structure of 100 nm.

Functional Gradient Alumina Ceramics with Controlled Porosity

2007 ◽  
Vol 333 ◽  
pp. 223-226
Author(s):  
Jana Andertová ◽  
Jiří Havrda ◽  
Radek Tláskal
Keyword(s):  
Sol Gel ◽  
Slip Casting ◽  
Physical And Mechanical Properties ◽  
Alumina Ceramics ◽  
Casting Method ◽  
Functional Gradient ◽  
Variable Porosity ◽  
Controlled Porosity ◽  
Sol Gel Transition ◽  
Gel Transition

The work deals with preparation of functional gradient alumina ceramics with controlled porosity by slip casting method of aqueous alumina suspension containing pore-generating agent. The sol-gel transition of AlO(OH) was employed to stabilize pore-generating agent in the suspension. The composite bodies with layers of variable porosity were prepared. Based on dilatometer measurement the admission difference of irreversible dilatation changes #αirr between compounded layers was determined in order to prepare defect free bi-layer bodies. The dependence of physical and mechanical properties of as fired composite bodies on the porosity value was expressed.

Effect of Cores on Photoluminescence of Hybrid SiO2-Coated CdTe Quantum Dots

2020 ◽  
Vol 20 (9) ◽  
pp. 5478-5485
Author(s):  
Cong Xie ◽  
Yubin Zhao ◽  
Yuxiang Song ◽  
Yingjie Liu ◽  
Yaya Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Stability ◽  
Sol Gel ◽  
Quantum Yields ◽  
Core Shell ◽  
Aqueous Synthesis ◽  
Pl Spectra ◽  
Cdte Qds ◽  
Sol Gel Process ◽  
20 Nm

Compared with conventional semiconductor quantum dots, hybrid SiO2 coated CdTe QDs exhibited high stability, long fluorescent lifetime, high photoluminescence quantum yields, and well biocompatibility. In this paper, CdTe QDs with tunable PL from green to red emitting were prepared by an aqueous synthesis. A sol–gel process resulted in CdTe QDs coated with a hybrid SiO2 shell contained CdS-like clusters to obtain red-shifted PL spectra, increased PL efficiency and high stability. The clusters were formed by the reaction of Cd2+ and S2− ions generated via the decomposition of thioglycolic acid. The clusters around CdTe cores created a core–shell structure which is very similar with traditional semiconductor core–shell QDs. After being coated with a hybrid SiO2 shell, the PL of green-emitting naked CdTe QDs was red-shifted largely (~30 nm) while the PL of yellowemitting CdTe QDs revealed a small red-shifted (~20 nm). Furthermore, The PL of red-emitting naked CdTe QDs was red-shifted much small (less than 10 nm). This phenomenon is ascribed to the change of band gap of CdTe cores with sizes. The red-shift of PL spectra is attributed to the CdS-like clusters around the core rather than the thickness of the hybrid SiO2 shell.

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