Document gDaMB2BdYgXEyyR6XaDVQzgqQ

EID2171H.TIF (2544x3263x2 tiff) UTAIUSMfOaoZ E. 1. d u P o n t d e N e m o u r s & C o m p a n y INCORPORATO P. O . BOX 1217 Pa r k e r s b u r g . W. V a . a e ioi POLYMER PRODUCTS DEPARTMENT cc: E. D. Champney, Jr. - D11070 H, R, Graef - Wilm. i, B, Armitage - CHS R. E. Putnam P. Thistieton File: 8-5 April 24, 1981 TO: FROM: F. A. FLUEGGE - F&F DEPT. FAIRFIELD, CT C. S. COPE - PPD PARKERSBURG, WV REC'D PftKA APR28 1981 ANALYSES OF TEFLON FELT SAMPLES FOR RESIDUAL C-8 FLUPRO SURFACTANT As requested, we have analyzed for residual C-8 APFC fluorosurfactant the samples of bleached and unbleached TEFLON felt supplied by you. The method of analysis consisted of first boiling the samples in dilute aqueous phosphoric acid solution (in the presence of a nonvolatile, nonionic wetting agent, "Triton" X-100) and condensing the overhead vapor. The distillate, after neutralization with 0.1N NaOH, was analyzed for C-8 by a chloroform/blue dye colorimetric extraction method. While the method is not specific for C-8 APFC, the results are expressed in terms of equiva lent C-8 APFC (M.W. = 431). Results on the two samples were as shown below. In each case, a 50-g quantity of felt was cut into approximately 1/2-inch squares for analysis. Additional detail is given in Table I, appended. Felt Type Approx. Thickness, Ppm (Wt.) of Equiv. C-8 APFC Inches Based on Dry Sample Weight XT-7700 (unbleached) XT-7800 (bleached) 0.035 0.062 3.5 0.7 The level of residual C-8 APFC found on XT-7700 is comparable with that we have typically found, using the same method, on TEFLON "fine powder" products, which are derived from aqueous dispersion manufactured using C-8 APFC as dispersing agent. In a general letter dated 4/2/81, F. N. Aronhalt,Rational Sales Manager of the Fluoropolymers Division of PPD, informed our customers that, "With the exception of aqueous dispersions, there is no significant residual FC-143 [3M Company's C-8 APFC] in any of the fluoropolymer resins which we sell." Based on the results obtained for the felt samples, it would therefore appear reasonable to conclude that they also contain "no significant residual FC-143". LWB000768 There's a world of things we're doing something about 00001 EID217111 EID217112.TIF (2544x3266x2 tiff) F. A. FLOEGGE 2 April 24, 1981 Please call (863-4296} if you need any further information with regard to these analyses. GSC/plc Attachment O0217H2 000012 ooooi: CtUiCQtS EID2171i3.TIF (2544x3265x2 tiff) TABLE I ANALYTICAL DATA TOR ftFLOW FELT SAMPLES Sple Weight Taken for Analysis, k Voltes of Distillt, ul Voluae of Titrant. 1 HicTOgrsa* C-B qulv. Pound In 50 al Aliquot of Titrated Distillate ?CRC372 ! A Method) Parts per Million of C-8 Equlv* Dated on Dry Saovle Weleht XT-7700 19.7 821 7.1 10.5 3.5 3tT-7800 50.0 818 5.4 2 (close to liait of detectability) 0.7 CSC/plc 4-24-B1 U0008A*]