Drying control chemical additives

L. L. Hench, Use of drying control chemical additives (DCCAs) in controlling sol-gel processing, in L.L. Hench and P. Uhlrich (Eds.), Science cf Ceramic Chemical Processing. Wiley, New York, 1986, pp. 52-65,... 

The nanostructure of aerogels could be used for gas-filtering purposes in the range from 20 to 100 nm [79]. In contrast to other materials for this purpose, because of their high porosity aerogels allow a relatively high gas flow. The pore size distribution can be influenced via drying control chemical additives [80]. 

Convective drying at very low drying rates or using the drying control chemical additive (DCCA)... 

DCCA Drying control chemical additives. Additives, in the sol-gel process before gelation, which permit to obtain uncracked dry monoliths with a relative high specific pore volume... 

Explain the meaning of the term drying control chemical additive (DCCA). Briefly describe the role of DCCAs in drying. What drawbacks do you see with the use of DCCAs ... 

DCCA Drying Control Chemical Additives. Chemicals such as oxalic acid, tetramethylorthosilicate (TMOS) and dimethyl formamide, which improve drying and produce larger pores in gels. See SOL-GEL PROCESS. 

The TEMPOL probe was also used to characterize the sol-gel silica with N,N-dimethylformamide (DMF) added as a drying control chemical additive (Itoh, 2001). The hyperfine coupling constant An decreased from 1.70 mT at DMF7TMOS = 0 to 1.61 mT at DMF/TMOS = 2.5 as shown in Figure 20-9. The 1.61 mT in the gels was... 

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