General. Kel - F 6061 was provided by 3M corporation. Neoflon M400H was provided by Daikin corporation. All other reagents were purchased from Aldrich Chemical company and used as received.
IR spectra were recorded using a Perkin Elmer 1600 FT - IR spectrometer. ATR - IR spectra were collected with a Perkin Elmer Spectrum 2000 FT - IR spectrometer interfaced to a Harrick Split - pea attenuated total internal reflection (ATR) microscope. Scanning electron micrographs were obtained on a Philips 505 SEM spectrometer. Combustion analyses were performed by Galbraith Laboratories, Inc.
Preparation of PCTFE - CO2H
PCTFE (1.04 g, 8.6 meq), 3.04 g (13.8 mmol) Cr(CO)6, and 2 ml of water were suspended in 50 ml DMF under nitrogen. The resulting slurry was stirred at 90 oC for four days. Sublimed metal carbonyl reagent was washed back into the reaction flask by small amount of DMF. The green slurry was filtered and washed sequentially with hexane, acetone, methanol, water and methanol again. The dark brown product was purified using Soxhlet extraction. The resulting product was dried in an Abderhalden apparatus with refluxing toluene and reduced pressure. The product was further characterized using titrimetric analysis.
IR (KBr) 3490 (br), 1680, 1400, 1358, 1278, 1200, 1125, 970 cm -1. Titrimetric analysis: 0.392 meq/g ion exchange capacity for Kel - F and 0.239 meq/g for Neoflon.
Procedure for titrimetric analysis
A slurry of polymeric acid and 3M HCl was stirred at approximately 80 oC for 3 hours. The resin was filtered on a Buchner funnel and washed with distilled water. This sequence was repeated twice. The sample was then dried in an Abderhalden apparatus with refluxing toluene and reduced pressure overnight. The sample was then titrated as follows: In a mixture of 0.5 g of acid and 0.5 g NaCl was added 10 ml distilled water and 3 - 5 ml of methanol. The reaction mixture was stoppered and sonicated overnight. Phenolphthalein (3 - 5 drops) was added to this mixture and titrated against 0.04 M standardized NaOH solution. Ion exchange capacity was determined to be 0.39 meq / g for modified Kel - F and 0.239 meq / g for modified Neoflon.
LOCATION OF AUTHORS