Highly Hydrophobic Carbon Black Obtained by Covalent Linkage of Perfluorocarbon and Perfluoropolyether Chains on the Carbon Surface

Abstract

Perfluorocarbon chains, that is, perfluoroethyl, CF3CF2−, perfluoro-n-propyl, CF3CF2CF2−, perfluoro-iso-propyl, (CF3)2CF−, and perfluoropolyether (PFPE) residues, were covalently bonded on the surface of a carbon black using perfluorodiacyl and PFPE peroxides. Thermal decomposition of the fluorinated peroxides allows the covalent linkage of fluorinated radicals to the polycyclic aromatic structure of the carbon black. Contact angle measurements in agreement with XPS data revealed a gradual enhancement of the water repellence with increasing fluorine content on the surface. When perfluoroalkyl chains were bonded to the carbon black the morphology and the surface areas of the modified carbonaceous materials were mostly retained as shown by BET and SEM analyses

Wettability of colloid-imprinted carbons by contact angle kinetics and water vapor sorption measurements

“…The water droplet was fully absorbed by the VC pellet after ca. 9 s. This phenomenon can be attributed to the hydrophilic surface of VC and the porous structure of the pellet, as was also observed by other researchers [69]. The porous structure of these pellets includes both the internal pores of each particle and the void space between the individual particles that constitute the pellets.…”

Hydrophobic carbonaceous materials obtained by covalent bonding of perfluorocarbon and perfluoropolyether chains

“…1b-d). 21 High resolution XPS analyses in the typical zone of F-bonds showed a sharp 1s peak at 690 AE 0.3 eV, associated to the presence of organic F-C bonds. 28,29 Samples with high percentage of fluorine showed a second peak approximately at 293.4 eV ( Fig.…”

“…In our previous works 20, 21 we observed by EPR analyses that perfluoroethyl (PFE), perfluoro-n-propyl (PFnP) and perfluoroisopropyl (PFiP) radicals are respectively generated during the decomposition of peroxides 1-3. In fact the mechanism of the thermal decomposition of PFDA peroxides involves the concerted dissociation with the simultaneous homolytic fission of C-C and O-O bonds, as described in literature.…”

“…21 The data analyzed indicated that there is a fluorination threshold difficult to exceed. 21 The data analyzed indicated that there is a fluorination threshold difficult to exceed.…”

An Environmentally Friendly Class of Fluoropolyether: α,ω-Dialkoxyfluoropolyethers

“…[1]. Concerning the impacts of fluoroformates on the climate, since fluorinated esters are known to be easily hydrolyzed [46,47], it is usually assumed that they can be easily removed though wet deposition; therefore Andersen et al [1] deduced that formate CH 3 O(CF 2 CF 2 O) n C(O)H is not expected to be persistent or pose any significant environmental hazard. However, Bravo et al [48] assumed that the highly fluorinated nature of fluoroformates may decrease their solubility in water and could contribute a significant indirect GWP.…”