Trifluoropropylmethyl siloxane

Detailed information on the copolymerization of cyclic trifluoropropylmethyl-siloxane trimer and octamethylcyclotetrasiloxane is also very limited in the open literature26 27 . Recently, preparation of various amine terminated (dimethyl-tri-fluoropropyl,methyl)siloxane oligomers with varying molecular weights and backbone compositions has been reported 69115 ll7). Table 11 shows various properties of the oligomers produced as a function of composition. These types of modification play very important roles in determining the solubility characteristics and hence the compatibility of resultant polysiloxanes with other conventional organic monomers... 

Iliis paper descnbes a novel contact lens materim based on a methacrylate end capped poly (trifluoropropylmethylsiloxane)(TET), octafluoropentyl-methacrylate (OFPMA) and a wettmg agent 2-vinyl-4,4-dimethyl-2-oxazolin-5-one (VDMO). The trifluoropropylmethyl siloxane, fluorinated methacrylate methacrylate and VDMO in the correct concentration provide a lipid resistant, oxygen permeable, hydrophilic contact lens material. 

M. Cypryk, B. Delczyk, A. Juhari, K. Itoynov, Controlled synthesis of trifluoropropylmethyl-siloxane-dimethylsiloxane gradient copolymers by anionic ROP of cyclotrisiloxanes, J. Pol. Sci. Part A Pol. Chem. 47 (4) (2009) 1204-1216. 

The incorporation of bulky groups into the silicone chain would be expected to raise and T. Attempts have been made to do this without sacrificing the high-temperature stability of the silicones. One such material is p-bis(dimethylhydroxysilyl) benzene, made fromp-dibromobenzene and (013)2 SiCl2 by the Grignard reaction [12]. Copolymers with dimethylsiloxane are also possible. Fluorosilicone elastomers are based on trifluoropropylmethyl siloxane ... 

As predicted by theory, the position of the ring/chain equilibrium was found to be independent of the nature of the redistribution catalyst employed (acid or base) (4,13,24- ) and of the specific inert solvent used (26). Russian authors (4,27) equilibrated mixtures of eyelosiloxanes comprised of dimethylsiloxane (75 mole %) and either trifluoropropylmethyl, cyanoethylmethyl, or cyanopropylmethyl siloxane (25 mole %) in acetone at a siloxane repeating unit concentration of 0.833 moles/A. They measured the dipole moments of the respective cyclosiloxanes, [(CH3)9SiO]3[Si(CH3)R0j>, to be 2.76 for R = trifluoropropyl, 3.45 for R cyanoethyl, and 3.58 in the case of R cyanopropyl. The equilibrium weight fraction of rings,... 

Bouanani et also reported the use of miniemulsion polymerization for the encapsulation of acid-treated montmorillonite within a fluorinated cyclo-siloxane [l,3,5-tris(trifluoropropylmethyl)cyclotrisiloxane]. Figure 1.12 shows the X-ray diffractograms of the pristine montmorillonite, acid-treated montmorillonite and nanocomposite before and after polymerization. The diffraction peak for the pristine montmorillonite was observed at 13.5 A, which was shifted to 18.01 A° after acid treatment. The authors opined that the observed larger basal plane spacing may be a result of interlamellar water layers due to the acid treatment and thus reflects the change in interlayer cations and their... 

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