The synthesis of poly(VDF-ter-TFMA-ter-HFP) terpolymers (where VDF, TFMA, and HFP stand for vinylidene fluoride, R-trifluoromethacrylic acid, and hexafluoropropylene, respectively) and their blends with silica filler for preparing original fluorocomposites are presented. First, the radical terpolymerization of VDF, TFMA, and HFP by iodine transfer polymerization without any surfactant was investigated in the presence of 1,6-diiodoperfluorohexane as the chain transfer agent. TFMA monomer was well incorporated, and the terpolymers were obtained in good yields (>65%). The microstructures of the produced terpolymers were characterized by 1 H and 19 F NMR spectroscopy to assess the amounts of each comonomer, the molecular weights, and the nature of the end groups of the copolymers. Molar percentages of VDF, TFMA, and HFP were in the 45-80, 12-53, and 1-8 ranges, respectively, whereas the molecular weights of the resulting terpolymers were ca. 5400-12 600 g 3 mol -1 . End groups were VDF-I only with a high amount of CH 2 CF 2 -I. Then, these poly(VDF-ter-TFMA-ter-HFP) terpolymers were involved in the preparation of the fluorinated polymers/silica nanocomposites by sol-gel reactions in the presence of tetraethoxysilane and silica nanoparticles under alkaline and acidic conditions, respectively. Interestingly, poly(VDF-ter-TFMA-ter-HFP) terpolymer/silica nanocomposites, which were prepared under alkaline conditions, showed exceptional thermal properties because they were found to exhibit almost no weight loss up to 800 °C.

Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [R F -(DOBAA) n -R F ] in silica nanocomposite can exhibit a nonflammability, even after calcination at 800 1C, through the formation of ammonium hexafluorosilicate during nanocomposite reactions. In contrast, the lack of formation of ammonium hexafluorosilicate during the usual composite reactions affords a flammable behavior for the R F -(DOBAA) n -R F oligomer in silica nanocomposite. Ammonium hexafluorosilicate is formed as a result of the dehydrofluorination of amido protons [-C(¼O)NH-] in R F -(DOBAA) n -R F oligomer, with fluorine atoms in the oligomers catalyzed by both ammonia and silica nanoparticles in the composite reactions. In contrast, the lack of dehydrofluorination in the nanocomposite reaction under acidic conditions affords the usual flammable behavior for the oligomer.

Fluoroalkyl end-capped acrylic acid oligomer [R F-(ACA) n-R F ] reacted with tetraethoxysilane and silica nanoparticles in the presence of low molecular weight aromatic compounds [Ar-H] such as cetylpyridinium chloride (CPC) and bisphenol AF under alkaline conditions to afford R F-(ACA) n-R F / SiO 2 nanocomposites-encapsulated Ar-H in 47-94% isolated yields. These fluorinated silica nanocomposites-encapsulated Ar-H can exhibit no weight loss behavior corresponding to the contents of Ar-H after calcination at 800 C under atmospheric conditions, although fluoroalkyl end-capped acrylic acid oligomer in the nanocomposites decomposed completely under similar conditions. UV-vis spectra of well-dispersed methanol solutions of R F-(ACA) n-R F /SiO 2 /CPC nanocomposites before calcination show that CPC can be encapsulated into fluorinated silica nanocomposites with encapsulated ratios: 23-43%. The fluorinated nanocomposites after calcination was found to exhibit a higher antibacterial activity related to the presence of CPC in the composites. Encapsulated bisphenol AF into R F-(ACA) n-R F /SiO 2 nanocomposites before and after calcination at 800 C can exhibit a good releasing ability toward methanol with released ratios: 48 and 26%, respectively. 1 H MAS NMR, HPLC analysis, and LC-MS spectra of R F-(ACA) n-R F / silica nanocomposites-encapsulated bisphenol AF also showed the presence of bisphenol AF in the nanocomposites even after calcination at 800 C under atmospheric conditions. These findings suggest that CPC and bisphenol AF can exhibit a nonflammable characteristic in the fluorinated silica nanocomposites. V

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