کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1622578 | 1516401 | 2009 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Physical properties of sodium silicate based silica aerogels prepared by single step sol-gel process dried at ambient pressure
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Physical properties of sodium silicate based silica aerogels prepared by single step sol-gel process dried at ambient pressure Physical properties of sodium silicate based silica aerogels prepared by single step sol-gel process dried at ambient pressure](/preview/png/1622578.png)
چکیده انگلیسی
The experimental results on physical properties of water glass (sodium silicate) based silica aerogels prepared by single step sol-gel process, dried at atmospheric pressure are reported. The hydrolysis and condensation reactions of the sodium silicate precursor proceeded with tartaric acid as a catalyst. The hydrogel was vapour passed in order to remove sodium salt from the gel network. Solvent exchange was carried out using methanol and hexane as a solvents. Finally, surface chemical modification of the gel was done using trimethylchlorosilane (TMCS) followed by ambient pressure drying of the gel up to the temperature 200 °C. To get good quality aerogels various sol-gel parameters such as water vapour passing period varied from 0.5 to 2 h, gel aging from 1 to 4 h, Na2SiO3/H2O molar ratio from 3 Ã 10â3 to 1.5 Ã 10â2, tartaric acid/Na2SiO3 molar ratio from 0.3 to 1.9 and TMCS/Na2SiO3 molar ratio from 4.8 to 12. The aerogels were characterized by percentage of volume shrinkage, bulk density, porosity and hydrophobicity. The hydrophobicity of the aerogel was confirmed by Fourier Transform Infrared (FTIR) Spectroscopy and contact angle measurements. Microstructural studies have been carried out by Scanning Electron Microscopy (SEM) and nitrogen adsorption BET analysis. From the TGA-DTA studies of the aerogels, it was found that the aerogels were thermally stable up to 470 °C. Low density (â¼0.066 g/cm3), high hydrophobicity (â¼145°), high porosity (â¼97 %), high pore volume, surface area of 510 m2/g aerogels have been obtained for Na2SiO3:H2O:tartaric acid (C4H6O6):TMCS molar ratio at 1:166.6:2.5:12 respectively with half an hour water vapour passing.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 476, Issues 1â2, 12 May 2009, Pages 397-402
Journal: Journal of Alloys and Compounds - Volume 476, Issues 1â2, 12 May 2009, Pages 397-402
نویسندگان
Jyoti L. Gurav, A. Venkateswara Rao, A. Parvathy Rao, D.Y. Nadargi, S.D. Bhagat,