Patent ID: 6828388
Filing Date: 2004-12-07
Classification: B29D,C08F,G02B

Abstract:
Amorphous perfiuorinated or fluorinated polymers containing an amount lower than 0.05 mmoles/kg polymer of each of the following ionic end groups: COF, COOH their esters or salts, when the used determination method for said end groups is the Fourier Transform IR spectroscopy by NicoletÂ® Nexus FT-IR equipment (256 scannings, resolution 2 cmâˆ’1), wherein on a sintered polymer powder pellet having a 5 mm diameter and thickness from 50 to 300 microns, a scanning between 4,000 cmâˆ’1 and 400 cmâˆ’1 is initially carried out, then maintaining the pellet for 12 hours in an environment saturated with ammonia vapours; and finally recording the IR spectrum under the same conditions of the initial IR spectrum; elaborating the two spectra by subtracting from the signals of the spectrum relating to the untreated sample (initial spectrum) the corresponding ones of the specimen spectrum after exposure to ammonia vapours, obtaining the â€œdifferenceâ€  spectrum, which is normalized by the following equation: &OpenCurlyDoubleQuote;Difference&it;â€ƒ&it;spectrum&CloseCurlyDoubleQuote;[pellet&it;â€ƒ&it;weight&it;â€ƒ&it;(g)/pellet&it;â€ƒ&it;area&it;â€ƒ&it;(cm2)]measuring the optical densities related to the end groups which have reacted with the ammonia vapours, converting then the optical densities in mmoles/kg polymer using the following extinction coefficients where appropriate:the group COOH at a frequency 3557 cmâˆ’1 (OH stretching) has an extinction coefficient of 165 1.molâˆ’1.cmâˆ’1: the same group COOH at a freauencv 1813 and 1775 cmâˆ’1(CO stretching): has an extinction coefficient of respectively 230 and 1700 1.molâˆ’1.cmâˆ’1: the group COF at a frequency 1884 cmâˆ’1 (CO stretching) has an extinction coefficient of 215 1.molâˆ’1.cm1; the group CONH2 at a frequency 3555 cmâˆ’1 and 3438 cmâˆ’1 (NH2 resoectively asymmetric and symmetric stretching) has an identical extinction coefficient of 220 1.molâˆ’1.cmâˆ’1; the group CONH2 at a frequency 1587 cmâˆ’1 (NH2 deformation motion) has an extinction coefficient of 220 1.molâˆ’1.cmâˆ’1; and the group CONH2 at a frequency 1768 cmâˆ’1 (CO stretching) has an extinction coefficient 940 1.molâˆ’1.cmâˆ’1.