Document k27X1k0GNREXDXXXNBV0Jjkn

I AR226-3333 FLUOROPOLYMERS 81-4 PAGE 10 3* Measurement of Residual C-8 Fluorosurfactant Levels on Various Products - C. S. COPE !: "' Following the report from 3M Company that "Fluorad" FC-143 (C-8 APFC) surfactant had been found teratogenic in tests with laboratory animals, we received several company requests for analytical determination of residual C-8 conpentrations^n v a r i o u s f ^ ^ m m U i H P ^ o d u c t s . Included were two types ofP B M ^ B M f e l t prgguced by F&FT)epartment's Fairfield, Conn., plant, a sample o f ^ P H H I H B ^ p g i a s s cloth manufactured b y f l h H H H H H H M B ( s u b mitied by R. J, Cavanaugh of Research), and two sgjppletgf T E - 9 7 2 4 - j f l ^ B M B P F A baited powder (prior to extrusion) manufactured a t Q B B H (analysis requested b y P. Thistleton of the Technical Department). As a reference point concerning residual levels of C-8 APFC on our ______ Jproducts, it may be noted that the Customary Advisory Letter issued to our customers on 4-1-81 by the Sales Division stated: "With the exception of aqueous dispersions, there is no significant residual FC-143 in any of the fluoropolymer resins which we sell." This statement is not inconsistent with the fact that very low levels, of the order of 1-5 ppm, of residual C-8 APFC - a v ^ ^ n detected (using a method which is not specific for C-8) in the past on ^ M ^ ^ f i n e powders and granular resins, the main products we sell in dry, bulk form in the unextruded condition. (Extruded resins should contain even lower levels of residual C-8.) Analyses of all these samples were performed by boiling the samples in a dilute aqueous solution of phosphoric acid in the presence of a nonvolatile, nonionic detergent ("Triton" X-100). Perfluorocaprylic acid is sufficiently volatile at 100C that it steam-distills off under these conditions. The C-8 in the distillate is then analyzed by the chlofoform/Azure A (a-blue dye) colori metric method, sensitive to about 2-3 micrograms. The method is nonspecific for C-8, and other ionic surfactants can, in principle, interfere. . In no case among the rec .es was a residual C-8 concentration above the range typically found on! ine powder detected. For the F&F felt samples, values of 3.5 ppm (un felt XT-7ZHP) and 0.7 ppm (bleached felt XT--7800) were obtained. Fot the (equivalent to 3.95 ppm based o: _ fabric, we found 0.35 ppm solids present). For the TE-9724-J samples, concentrations of 2.8 anS 1.0 ppm were found, Results have been trans- mitted in writing to those who requested the analyses. The most recent analyses of residual -8 APFC on fine powder were obtained in March on a set of three samples of J P H H H 6 4 submitted by E. H. Stueber of the Technical Department. Tygg of these samples were from lots which had performed poorly in wire-coating while the third was a control which performed normally. "Tfechnical's request for C-8 analyses was prompted by a desire to test, in the absence of any clear-cut distinctions in the normal characterization data, whether possible differences in residual C-8 level might account for the differences in fabrication behavior. The two unsatisfactory lots, with residual C-8 levels of 4.2 and 2.5 ppm, were found to be somewhat above the control (1.5 ppm) in this respect, but by no means enough so to be considered unusual. Furthermore, tests done years ago showed that Company Sanitized. Does not contain TSCA CBI FLUOROPOLYMERS 81-4 PAGE 11 i ^ PaSuC extrusion performance of fine powder was not significantly affected either by removing the last traces of residual dispersing T O r 1by/ ep0sltinS dispersing agent back onto the dry S e r (by iss ~ Company Sanitized. Does no! contain TSCA CBI r \ i FLUOROPOLYMERS 81-4 PAGE 12 4- (M? Fluorosurfactant Analyses on Samples Received from the FEP Area - C. S. COPE ' "' -- r p p a- / eq"ef ! , Were reefeived from Technical Department personnel in the FEP Area for C-8 fluorosurfactant analyses on several polymer and water samples. The polymer samples were taken from t h e ^ B l i M l D r y e r and asso ciated equipment at a time when dryer performanceV a s being questioned. The water samples were taken as part of the program to establish a material balance on C-8 distribution in the FEP Area. In a U the C-8 was recovered from the samples by distillation in the presence of dilute aqueous phosphoric acid. Indications are that this treatment is relatively effective in separating out any "in situ" dispersing frr . M i l C_8,,APFC* xWth the polymer samples, a nonvolatile, nonionic d i a M i w ^ ^rtn x_10) was added to promote wetting. Analyses of the f" ". ^ polymer samPles happened to be carried out by titration with cetyltrimethylammonium bromide, whereas with the distillates from the aqueous samples (run at a later date), the chloroform/Azure A method was employed. Results of the analyses are presented in Table II-CSC. . measured C-8 concentrations on the polymer samples provided tew surprises, it having been established earlier that t h e r ryer, serves to remove most of the C-8 from the (wet) feed entering from t t e f a K ^ r Si-fT,f^C% i he C_8 5emOVed fr0m the discharges through the dryer vent line leading to the water scrubber, a polymer plug in this line would to contain more C-8 than the dry polymer exit the dryer. Dry removed from the rotor of the dryer would be expected to have a C-8 C-8 leielonartb1^ th thf of thedryer product. Two earlier measurements of C 8 level on the dryer product gave values of 6 and 34 ppm, bracketing the value of 17 now obtained on the polymer scraped from the dryer rotor.S fmTM aon<;entratlon of ppm (0;i95%) found on the sample taken mjfre lid of the screw conveyor noy located between the discharge of the S R i e c t e r b / ntranCw t0 the -- much higher than at wMri J T i' prevlous measurements o i & g U | p ress product samples, which had equivalent C-8 concentrations of 0 . 0 4 2 r f n d 07066?. The differences 8ref er When diff* ~ n c e s m water content are taken Into account r a t L r 1^ r rSing.^8ent 18 expected to be Predominantly adsorbed on the polymer, fto t S hi*? Phafe)* The recent sample contained 70Z water and 14-8%` respectively, in the earlier samples, C~8 COncentratons` expressed on a water-free basis, is f t S i b u i a b S T b 1 vr?e\ f mafntude* We Postulate that this difference the ieSod J h i i Ck~2f kaSe f C-S-containing vapor from the dryer during 2 * ? a J i dryer Pfoimance was unsatisfactory. The C-8 would be l-Liidd, ithhef tTMop rof,,whMinchewnaSsedexUptosend tCo01thesuarmfbaiceenst* astum<o*spherteh.e screw conveyor Company Sanitized. Does not contain TSCA CB1 FLUOROPOLYMERS 81-4 PAGE 13 TABLE II-CSC -- -8 FLUOROSURFACIAHT ANALYSES ON SAMPLES FROM THE PEP AREA (Submitted by A. R. Behnke and J. R. Evitts, Technical Department) Sample Identification Date Submitted Measured Concentration of Equivalent C-8 APFC. ppm (Based on Initial Weight) Polymer Samples (Analyzed by CTMAB Titration) aped from rotor of Dryer Sai Le of .plui ; found in vent line of! Dryer. 3/30/81 3/30/81 Dust sample'from Conveyor feeding Dryer (70% H 20, 4/2/81 17 170 1950 Water Samples (Analyzed by CHClg/Azure A Method) _ J100 Coagulator Effluent M(Batch 21-4111) 00 PK (First) Rinse water (BBaatch 21-4111) 4/27/81 4/27/81 260 15 (0.12% polymer solids present) Company Sanitized. Does "no! contain TSCA CBI