Variation of the specific surface area and porosity of zinc oxide prepared in various atmospheres

1976 ◽  
Vol 26 (4) ◽  
pp. 199-206 ◽  
Author(s):  
Raouf Sh. Mikhail ◽  
Nabila M. Guindy ◽  
Ismail T. Ali
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area

Effect of ZnO Particle Size on the Curing of Carboxylated NBR and Carboxylated SBR

2004 ◽  
Vol 77 (2) ◽  
pp. 214-226 ◽  
Author(s):  
G. R. Hamed ◽  
K.-C. Hua
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Cure Rate ◽  
Surface Areas ◽  
Diffusion Limited ◽  
Rate Of Dissolution ◽  
Oxide Particles ◽  
And Diffusion

Abstract A carboxylated nitrile rubber (XNBR) and a carboxylated SBR (XSBR) were mixed with zinc oxide particles of different specific surface areas (“S”, 35 m2/g; “M”, 3.5m2/g; “L”, 0.5 m2/g) and cure behavior at 165 ºC studied using oscillating disc rheometry. Without added zinc oxide, both raw rubbers slowly stiffen over many hours of heating. This is probably due to condensation of carboxyl groups to form anhydride crosslinks. XNBR compositions containing the finely divided “S” crosslink much more rapidly. Full cure is reached after about 10 minutes of heating. Cure rate decreases markedly as the specific surface area of the ZnO decreases. A composition containing “M” at twice stoichiometry requires about an hour to cure well, while with “L”, about 10 hours are required. In contrast, curing of the XSBR depends little on the specific surface area of the ZnO, either with “S” or “L”, curing is essentially complete after 30 minutes. After simply mixing ZnO into either rubber, it remains as a dispersed particulate. With XNBR, curing appears to be controlled by the rate of dissolution and diffusion of ZnO, while, with XSBR, reaction is not diffusion limited and may be confined to regions near particle surfaces.

Influence of Zinc Oxide Nanograins on Properties of Epoxidized Natural Rubber Vulcanizates

2017 ◽  
Vol 748 ◽  
pp. 79-83 ◽  
Author(s):  
Rudeerat Suntako
Keyword(s):  
Mechanical Properties ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Epoxidized Natural Rubber ◽  
Precipitation Method ◽  
Cure Characteristics ◽  
Permanent Set

Zinc oxide (ZnO) nanograins are synthesized by precipitation method filled epoxidized natural rubber compared to conventional ZnO. The synthesized ZnO nanograins are characterized by X-ray diffraction and transmission electron microscopy and found that average primary size of ZnO synthesized around 40 nm and the specific surface area of 28.72 m2 g-1. Furthermore, the cure characteristics, rubber mechanical properties and permanent set were investigated. The obtained results are found that the ZnO nanograins significantly affected to cure characteristics, rubber mechanical properties and permanent set. This is due to small grain size and large specific surface area.

scholarly journals W-Sn Mixed Oxides and ZnO to Detect NOx and Ozone in Atmosphere

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 836
Author(s):  
Ambra Fioravanti ◽  
Sara Morandi ◽  
Alessia Amodio ◽  
Mauro Mazzocchi ◽  
Michele Sacerdoti ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mixed Oxides ◽  
Gas Sensing ◽  
Molar Fraction ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
X Ray

Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction, specific surface area measurements, UV-Vis-NIR and IR spectroscopies. The gas sensing measurements highlighted that ZnO is more performant in form of nanoprisms, while W-Sn sensors offer a better response towards NOx and ozone with respect to pure WO3.

scholarly journals Preparation and Characterization of Fly Ash Coated with Zinc Oxide Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3550 ◽  
Author(s):  
Wang ◽  
Wang ◽  
Bai ◽  
Yang ◽  
Wang
Keyword(s):  
Zinc Oxide ◽  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ph Value ◽  
Composite Powders ◽  
Coating Agent ◽  
Average Grain Size ◽  
Effects Of Ph

Calcined fly ash (CFA) was first obtained by calcining fly ash (FA) at 815 °C for two hours. Then, composite powders of CFA coated with zinc oxide nanoparticles (ZnO/CFA, ZCFA) were prepared by heterogeneous nucleation method. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning electronic microscopy (SEM), Whiteness, and Brunauer-Emmett-Teller specific surface area (BET). Effects of pH value, reaction temperature and time, coating amount, solid-to-liquid ratio, the coating agent concentrations, and dropping speed on the whiteness of ZCFA powders were studied. It was shown that after coated with ZnO particles, the whiteness of CFA was increased from 27.0 to 62.6%, and the specific surface area was increased from 5.80 to 14.61 m2/g. Needle ZnO with the average grain size of 46 nm was deposited on the surface of CFA. Si–O–Zn–OH bonds were formed.

Zinc oxide aerogel-like materials with an intriguing interwoven hollow-sphere morphology for selective ethanol sensing

RSC Advances ◽  
2014 ◽  
Vol 4 (42) ◽  
pp. 21815-21818 ◽  
Author(s):  
Peipei Wang ◽  
Yongcun Zou ◽  
Yun Wang ◽  
Tianrui Chen ◽  
Jianxiong Gao ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Hollow Sphere ◽  
Large Specific Surface Area ◽  
Interconnected Porosity ◽  
Sensing Properties ◽  
Ethanol Sensing

Zinc oxide aerogel-like materials with interconnected porosity and large specific surface area have been prepared, showing excellent ethanol sensing properties.

scholarly journals NITROGEN THERMAL DESORPTION OF AS A CONTROL METHOD FOR DETERMINATION OF THE NANOPARTICLE SIZE IN COMPOSITIONS BASED ON ZINC OXIDE AND HYDROXYAPATITE

2021 ◽  
pp. 294-299
Author(s):  
Евгения Владимировна Мараева ◽  
Вячеслав Алексеевич Мошников
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermal Desorption ◽  
Control Method ◽  
Chemical Deposition ◽  
Bioactive Coatings ◽  
Sorption Method ◽  
Before And After

Работа посвящена анализу возможности применения метода тепловой десорбции азота для определения размеров наночастиц в композициях на основе гидроксиапатита и оксида цинка, изготовленных в форме таблеток с помощью ручного гидравлического пресса. Исходные порошки гидроксиапатита получены методом химического осаждения с использованием микроволнового излучения. С применением сорбционного метода БЭТ анализируется удельная поверхность порошков, составляющих композиции, до и после прессования, исследуется влияние состава композиций на удельную поверхность. Приводится расчет средних размеров наночастиц в композициях на основе результатов сорбционных измерений в рамках моделей сферических и стержневидных наночастиц. Область применения рассматриваемых материалов - медицина, в том числе использование в адресной доставке лекарств и в костной инженерии в качестве биоактивных покрытий, нанесенных на поверхность металлического биоимплантата. In this paper we consider the possibility of using the nitrogen thermal desorption method for determining the size of nanoparticles in compositions based on hydroxyapatite and zinc oxide. The compositions in the form of tablets were obtained using a manual water press. The initial powders of hydroxyapatite were obtained by chemical deposition using a microwave radiation. Using the BET sorption method, the specific surface area of the powders is analyzed before and after pressing, and the effect of the composition formulation on the specific surface area is investigated. The calculation of the average sizes of nanoparticles in composites is given on the basis of the results of sorption measurements within the framework of the models of spherical and rod-like nanoparticles. The field of application of the materials under consideration is medicine, including the use of nanocomposites in targeted drug delivery and in bone engineering as bioactive coatings applied to the surface of a metal bioimplant.

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