Fluoroalkyl end‐capped oligomer possessing a nonflammable characteristic in silica gel matrices even at 800°C under atmospheric conditions

Abstract

We succeeded in observing the similar solid‐state NMR spectra (1H‐magic‐angle spinning NMR spectra) of fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide oligomer [RF‐(DOBAA)n‐RF]/silica gel nanocomposite before and even after calcinations at 800°C. This finding suggests that RF‐(DOBAA)n‐RF oligomer in RF‐(DOBAA)n‐RF/silica gel nanocomposite can afford a nonflammable characteristic to exhibit no weight loss behavior even at 800°C under atmospheric conditions. In addition, we had good oleo‐ and hydrophobic characteristics on the modified glass surface treated with RF‐(DOBAA)n‐RF/silica gel nanocomposite even after calcination at 800°C as well as those before calcinations. Especially, RF‐(DOBAA)n‐RF/silica gel nanocomposite‐encapsulated cetylpyridinium chloride (CPC) possessing no weight loss characteristic even at 800°C exhibited a clear UV–vis absorption band around 260 nm related to the presence of CPC before and even after calcinations at 800°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Fluoroalkyl end-capped oligomers possessing nonflammable and flammable characteristics in silica gel matrices after calcination at 800 °C under atmospheric conditions

“…In fact, we have already reported that the 1 H MAS NMR spectra of the R F -(DOBAA) n -R F /silica nanocomposite (with the oligomer content in the composite at 23%, as determined by elementary analyses of fluorine), which exhibit no weight loss even after calcinations at 800 1C, can exhibit similar relatively sharp peaks at around 50 to À20 p.p.m. 17 These peak areas are almost the same as those before calcination at 800 1C. 17 Furthermore, it was previously reported that hexafluorosilicic acid can interact smoothly with amido segments in N,N-dimethylformamide to give a stable hexafluorosilicic acid-N,N-dimethylformamide 1:3 adduct.…”

“…17 These peak areas are almost the same as those before calcination at 800 1C. 17 Furthermore, it was previously reported that hexafluorosilicic acid can interact smoothly with amido segments in N,N-dimethylformamide to give a stable hexafluorosilicic acid-N,N-dimethylformamide 1:3 adduct. 18,19 Thus, the surface of smoothly encapsulated R F -(DOBAA) n -R F oligomer into silica gel nanomatrices through effective hydrogen bonding interactions of the amido protons in the oligomers and fluorines in ammonium Oligomer in composite Synthetic conditions Size of composite, nm (after calcination, nm) Weight loss (%) at 800 1C …”

“…14 However, the treatment of this R F -(DOBAA) n -R F /silica gel nanocomposite with aqueous HF afforded FT-IR spectra of R F -(DOBAA) n -R F oligomer similar to those of the original R F -(DOBAA) n -R F oligomer. 17 In contrast, these carbonyl bands were clearly observed in the R F -(DOBAA) n -R F /silica gel nanocomposite possessing flammability, and the same FT-IR spectra as that of the original R F -(DOBAA) n -R F oligomer were observed after treatment with aqueous HF. 16 Now, interestingly, the FT-IR spectra of the R F -(DOBAA) n -R F /silica gel nanocomposite possessing nonflammability (see Figure 2a) after treatment with aqueous HF showed a clear band at around 700 cm À1 in addition to those of the parent R F -(DOBAA) n -R F oligomer (see Figure 2b), although we could not detect such bands at all in the corresponding flammable R F -(DOBAA) n -R F oligomer (see Figure 2d).…”

Preparation of ionic liquid/silica nanocomposites possessing no weight loss characteristic after calcination at 800 °C

“…Similarly, ammonium-type and imidazolium-type ionic liquids such as TEON-TFSI, TBMN-TFSI, and EMI-TFSI were able to afford no weight loss behavior toward the corresponding ionic liquid/SiO 2 nanocomposites even after calcinaton at 800°C. Previously, we reported that fluoroalkyl end-capped oligomers possessing amido protons or sulfo groups can suffer the sol-gel reactions with TEOS and silica nanoparticles in the presence of aqueous ammonia to afford the corresponding oligomer/ silica nanocomposites possessing no weight loss behavior even after calcination at 800°C [20][21][22][23][24][25][26][27][28]. Especially, these fluorinated oligomers can afford the smooth dehydrofluorination of amido protons or sulfonic acid protons with fluorines in oligomers catalyzed by ammonia and silica nanoparticles to afford ammonium hexafluorosilicate during the sol-gel process [20][21][22][23][24][25][26][27][28].…”

“…Previously, we reported that fluoroalkyl end-capped oligomers possessing amido protons or sulfo groups can suffer the sol-gel reactions with TEOS and silica nanoparticles in the presence of aqueous ammonia to afford the corresponding oligomer/ silica nanocomposites possessing no weight loss behavior even after calcination at 800°C [20][21][22][23][24][25][26][27][28]. Especially, these fluorinated oligomers can afford the smooth dehydrofluorination of amido protons or sulfonic acid protons with fluorines in oligomers catalyzed by ammonia and silica nanoparticles to afford ammonium hexafluorosilicate during the sol-gel process [20][21][22][23][24][25][26][27][28]. The surface of these smoothly encapsulated fluorinated oligomer into silica gel nanomatrices through the effective hydrogen bonding interactions between the amido protons or sulfonic acid protons in oligomers and fluorines in ammonium hexafluorosilicate could possess an extraordinarily high oxidation resistance to exhibit a nonflammable characteristic during the calcination process at 800°C [20][21][22][23][24][25][26][27][28].…”