scholarly journals Use of a sol-gel hybrid coating composed by a fluoropolymer and silica for the mitigation of mineral fouling in heat exchangers

2016 ◽  
Vol 106 ◽  
pp. 427-431 ◽  
Author(s):  
Valeria Oldani ◽  
Gabriele Sergi ◽  
Carlo Pirola ◽  
Claudia L. Bianchi
1998 ◽  
Vol 519 ◽  
Author(s):  
Y. Yan ◽  
Z. Duan ◽  
D.-G. Chen ◽  
S. Ray Chaudhuri

AbstractThe insoluble, strongly hydrogen bonded organic pigment of 3,6-bis-(4-chlorphenyl)-l,4- diketopyrrolo [3,4-c] pyrrole was transiently blocked by adding carbamate groups, and consequently incorporated into organic-inorganic hybrid matrices by a sol-gel process. The homo- (pigment-pigment) and hetero-intermolecular (pigment-matrix) interactions were found to control both the assembly and dispersion of pigment molecules in the hybrid coating films. A weaker interaction between matrices and pigment molecules results in aggregation of the carbamate pigment in the methyl-silicate films. A stronger interaction forms a homogenous dispersion and coloration of the phenyl-silicate films. The as-prepared methyl- and phenylsilicate films doped with the organic pigment were distinguished by a morphology change and a blue (hypsochromic) shift in absorption from 550 to 460 nm. Thermal treatment can remove the carbamate groups and in-situ form the organic pigment in the hybrid films.


2005 ◽  
Vol 14 (1) ◽  
pp. 096369350501400 ◽  
Author(s):  
C. H. Zhang ◽  
Y. P. Bai ◽  
L. X. Liu ◽  
Z. Q. Zhang ◽  
Q. Y. Li

In this paper, epoxy/SiO2 hybrid coating was successfully prepared through sol-gel technique, the structure and thermal properties of epoxy/SiO2hybrid coating were investigated. First, γ-isocyanatopropyltriethoxysilane “(KBE-9007)” was used to modify the epoxy resin so that the ethoxysilane could be grafted on the epoxy resin. Nano-SiO2 precursor was synthesized by tetraethoxysilane(TEOS) through sol-gel technique. Then the modified epoxy resin and the nano-SiO2 precursor were mixed for 4 hours to let the macromolecules of epoxy resin graft on the surface of nano-SiO2, and modified nano-SiO2 precursor was obtained. At last, epoxy/SiO2 hybrid coating was produced by using the modified nano-SiO2 precursor. The graft reaction was confirmed by the analyses of FT-IR. The analyses of XPS indicated that there are lots of SiO2 particles and Si-C covalent bonds on the surface of epoxy/SiO2 hybrid coating, they also suggested that most TEOS had changed into SiO2 particles and Si-C covalent bond had been formed between epoxy resin and SiO2. The analyses of SEM fracture surface image of epoxy/SiO2 hybrid coating showed that SiO2 particles dispersed in epoxy matrix homogeneously and the size of the particles was between 50nm and 100 nm. Thermoanalysis Instrument was employed to detect the thermal properties of epoxy coating and epoxy/SiO2 hybrid coating, the results indicated that the thermal decomposition temperature of epoxy/SiO2 hybrid coating is 21.7 °C higher than that of epoxy coating, the thermal properties of the epoxy/SiO2 hybrid coating were improved because of the introduction of nano-SiO2.


2020 ◽  
Vol 141 ◽  
pp. 105540
Author(s):  
Linlong Meng ◽  
Haoxin Zhu ◽  
Bing Feng ◽  
Zhenhua Gao ◽  
Di Wang ◽  
...  

2014 ◽  
Vol 29 (9) ◽  
pp. 1025-1029 ◽  
Author(s):  
Litong Guo ◽  
Junlong Tian ◽  
Jing Wu ◽  
Baoe Li ◽  
Cheng Xu ◽  
...  

2005 ◽  
Vol 53 (16) ◽  
pp. 4455-4462 ◽  
Author(s):  
M SAKAI ◽  
M SASAKI ◽  
A MATSUDA

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 72 ◽  
Author(s):  
Simona Ortelli ◽  
Anna Luisa Costa

Organic–inorganic hybrid (ceramer) coatings were synthesized and deposited on the polyester nonwoven fabrics through the sol–gel process. This promoted the formation of an insulating barrier that was able to enhance the thermal stability and the hydrophobicity of fabrics. The hybrid phase is made of an organic network arising from different alkoxysilane precursors (trimethoxymethylalkoxysilane (TMEOS), 3-aminopropyl-trimethoxyalkoxysilane (APTMS), and tetraethylorthosilicate (TEOS)) and inorganic phase made of titanium dioxide TiO2 nanoparticles (NPs) and, in some cases, coated by P-based compound. The characterization of hybrid phase at liquid (size distribution and zeta potential of dispersed nanoparticles), dried state (crystalline phase, thermogravimetric (TGA), and Fourier transform infrared spectroscopic (FTIR) analyses), and on deposited coatings (contact angle, burn-out tests) aimed to find a correlation between the physicochemical properties of ceramer and functional performances of coated fabrics (thermal stability and hydrophobicity). The results showed that all ceramer formulations were able to improve the char formation after burn-out, in particular the highest thermal stability was obtained in the presence of TMEOS precursor and TiO2 NPs coated by P-based compound, which also provided the highest hydrophobicity. In conclusion, we presented an environmentally friendly and easily scalable process for the preparation of ceramer formulations capable of being formed into transparent, thermal-resistant, and hydrophobic fabric coatings, whose functions are extremely challenging for the textile market.


2011 ◽  
Vol 391-392 ◽  
pp. 505-510
Author(s):  
Yan Pang ◽  
Yao Chen ◽  
Qi Qiu ◽  
Fang Wang ◽  
Zhang Tao

Optically transparent hydrophobic inorganic-organic hybrid sols was obtained employing Tetraethylorthosilicate (TEOS), Methyltriethoxysilane (MTES), and Heptadecafluoro-1, 1, 2, 2-tetradecyl)trimethoxysilane (FAS), with nitric acid as catalyst. Hybrid coating was dip coated on glass slides. The results showed that the water contact angle of MTES modified SiO2 coating was only 105° . As the weight ratio FAS varied from 0 to 8 wt.%, the water contact angle reached as high as 116.5°. The coated glass presented transmittance of 92%, 2% higher than the non-coated ones. The increase in transmittance suggested an antireflective effect of the hybrid coating. With further SEM characterization of the surface morphology, we finally obtained the optimized optically transparent hydrophobic hybrid coating with the MTES/TEOS_as 1/1(molar ratio) and FAS as 2 wt.%.


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