SYNTHESIS OF FLUORINATED POLYSILOXANES .8. PROPERTIES AT LOW AND HIGH-TEMPERATURES OF POLYSILOXANES WITH FLUORINATED GRAFTS

The copolycondensation of commercial diols HO[SiCH3)2O]nH with fluorinated dichlorosilanes as CH3SiCl2(CH2)3O(CH2)2C6F13 and blocking agent H2C = CHSi(CH3)2Cl led to fluorinated polysiloxanes having vinyl end groups. The chemical (H-1, C-13, and Si-29 NMR) and physicochemical [viscosities, glass transition temperatures (T(g)'s) by DSC, and degradation temperatures (T(d)'s) by TGA] characteristics were determined. The properties of these polymers were compared with those of poly(dimethylsiloxane) (PDMS) and poly[methyl(trifluoropropyl)siloxane] at low and high temperatures, and it was shown that it was possible to prepare elastomers with T(g)'s lower than -100-degrees-C that do not exhibit a better high-temperature resistance. At temperatures above 300-degrees-C, the network has a behavior close to that of PDMS and much better than that of commercial fluorosilicones.