Yung K. Kim

The synthesis of fluoroether-fluorosilicone hybrid polymers

Abstract The replacement of the fluorocarbon segment in the general class of hybrid fluorocarbon-fluorosilicones by fluoroether units was investigated in order to improve low temperature properties without sacrificing high temperature performance. The effects of the co-reactant halogens (bromine and iodine) and metallic fluorides (potassium fluoride and cesium fluoride) on the product yields in the syntheses of the requisite α,ω-dihalo-F-ether intermediates [1] from the corresponding acyl or diacyl fluorides were studied. While a better yield was obtained with bromine than with iodine, the iodoperfluoroethers produced superior yields in the subsequent ethylene addition reactions, as expected. Potassium fluoride was preferable to cesium fluoride in the synthesis of the iodo-F-ethers, since cesium fluoride effects decomposition of the ethers.

The synthesis of α,ω-bis-(silyl)polyfluoroalkane derivatives

Abstract Fluorosilicones of the type, R 3 SiCH 2 CH 2 (CF 2 ) x CH 2 CH 2 SiR 3 where R equals CF 3 CH 2 CH 2 , CH 3 , Cl, and/or H and where x ranges from 1 to 10, were prepared either by the chloroplatinic acid or peroxide-catalyzed addition of appropriate silanes to CH 2 CH(CF 2 ) x CHCH 2 . The addition of CH 2 CH 2 to Y(CF 2 ) x Y, YBr or I, followed by dehydrohalogenation of the resulting YCH 2 CH 2 (CF 2 ) x CH 2 CH 2 Y provided the required dienes. While the free-radical induced addition of CH 2 CH 2 to Br(CF 2 ) 6 Br and BrCH 2 CH 2 (CF 2 ) 6 Br gave a high yield of BrCH 2 CH 2 (CF 2 ) 6 CH 2 CH 2 Br, the addition of CH 2 CH 2 to BrCF 2 CF 2 Br and BrCH 2 CH 2 CF 2 CF 2 Br under indentical conditions resulted in the formation of no more than a trace amount of BrCH 2 CH 2 CF 2 CF 2 CH 2 CH 2 Br. A similar unsuccessful result was obtained in an attempted addition of CH 2 CH 2 to BrCF 2 Br and BrCF 2 CH 2 CH 2 Br, indicating the importance of the chain length of Br(CF 2 ) x Br for the formation of α,ω-diethylene addition products. Although no complication was encountered in the peroxied-catalyzed addition of silane to CH 2 CH(CF 2 ) x CHCH 2 , the chloroplatinic acid induced addition of silane to the dienes yielded the corresponding rearranged mono-addition products, R 3 SiCH 2 CH 2 (CF 2 ) x -1 CFCHCH 3 , in addition to the diadducts, R 3 SiCH 2 CH 2 (CF 2 ) x CH 2 CH 2 SiR 3 . The decomposition of a reversely oriented platinum-olefin or platinum-diene complex without actual formation of the reverse adduct, , is thought to account for the rearranged mono-addition products.

Fluorosilicones as High Temperature Elastomers

Two types of fluorosilicone polymers are described, the poly (fluoroalkyl)siloxanes and the hybrid fluorocarbon silicones. The first type, represented by the structure (CF3CH 2CH2SiMeO)n exhibits good solvent resistance, thermal and oxidative stability and is commercially available in the form of rubber, sealants and fluids. The second type,

Fluoro-organofunctional silicon compounds. Synthesis of acetoxy, carbethoxy and hydroxy derivatives

Abstract The synthesis of fluoro-organosilicon compounds containing acetoxy, carbethoxy, or hydroxy groups in the organic portion of the molecule is described.