Document MMjd6OJvyr0Kbm6wjkYG6QoO9

MONTHLY REPORT P. P. BURKS JULY, 1981 I. OBJECTIVE Elim inate or control at safe le v e ls FC-143 exposure at Spruance and in trade. A. Commercialize interim process to produce impregnated yarns free o f detectable FC-143. IVQ'81 5^ II. SUMMARY FC-143, a fluorocarbon surfactant supplied by 3M Company and used in polymerization o f Teflon resin at Parkersburg, was reported by the vendor to have embryotoxic e ffe c ts in laboratory animals. Ayjpotential near term route* to elim inate FC-143 from our products, we are evaluating thermal treatment o f impregnated yam s, and d ia ly s is and ion exchange treatment o f Teflon dispersion. Heating o f impregnated and treated pack ages o f Teflon and Kevlar yarns in a bleaching oven fo r 3 - 5 hours at 190C removed a ll detectable FC-143. However, braided packing of Teflon fa ile d in tern al packing te s ts . I n it ia l tests indicated yarns meet s p e c if i cations. Causes o f fa ilu r e are being investigated. Packing tests o f Kevlar yarns are in progress. Tests o f alternate approaches, o n -lin e heating using hot r o ll s , and removal o f FC-143 by d ia ly s is or ion exchange w ill be complete in August. Work with A n aly tical Research w i ll determine i f heated FC-143 evaporates or decomposes, and w ill id e n tify decomposition products. I I I . DETAILS Tests in a plant bleaching oven showed FC-143 was removed from Teflon yam packages w ithin 3 hours, and from Kevlar yam packages in 3 - 5 hours. Using thermocouples imbedded in yam packages, we found 2.0 - 2.5 hours were required fo r core yam to reach the 190 oven temperature. Apparently, re moval o f FC-143 from packages, by sublimation or decomposition, requires about 1 - 2 hours at 190C. This value is roughly 2 - 4x the 0.5 hours in d i cated by A n alytical Research re su lts on small (<lgram) yarn samples. L ite ra ture reports and discussions with Polymer Products personnel indicate the probable mechanism is decarboxylation to y ie ld C0? and 1- hydroperfluoroheptane. The 50-fold excess o f Triton surfactant in the dispersion is believed to accelerate th is reaction by providing a high d ie le c t r ic medium and a source o f hydrogen ions. S. S. Shelburne o f A n a ly tica l Research is working to confirm th is mechanism using gas-phase infra re d analysis. The hydroperflouroheptane is believed non-toxic but no s p e c ific data have been found. The o n -lin e heating process w ill be tested using c r y s t a lliz e r r o lls in Nomex semi-works. This te s t w ill define time/temperature conditions needed to remove FC-143. Previous laboratory tests suggested 100% removal is p ossi b le a t residence times o f 5 - 10 seconds and yarn temperatures o f 250 - 300 I f successful, the o n -lin e process should provide less thermal d isco lo ra tio n o f yarn, and higher productivity than package heating. 000035 SPRO O l403 EID715274 /' P. P. BURKS - 2- JULY, 1981 Removal o f FC-143 from Teflon dispersion, before the yarn impregnation step, is being evaluated by ion exchange techniques at Spruance, and by u lt r a f i lt r a t io n (d ia ly s is ) te sts at two equipment vendors. U lt r a f ilt r a t io n forces solu tion (water and FC-143) through a semi-permeable membrane w hile retaining "Teflon p a rtic le s . A "Triton" solution is added continuously to maintain 60the % concentration o f "Teflon" p a rtic le s . Removal o f FC-143 may be retarded, in both ion exchange and u lt r a f ilt r a t io n , by binding to "Teflon" p a rtic le s . Results w i ll be av ailab le in August. IV. PROGRAM Complete packing tests with heated Kevlar yarns Timing 8/7 Define reason(s) fo r fa ilu r e o f Teflon packing 8B Define f e a s ib ilit y o f o n -lin e heating o f "Teflon" yarn using c r y s ta lliz e r r o lls . - Seri-works test - Product analysis 8/7 8B Define f e a s ib ilit y o f FC-143 removal from dispersion by ion exchange or d ia ly s is goal 8B Define mechanism of thermal elim ination o f FC-143 (Anal. Res.) 8B Complete technical and toxicology te s tin g o f altern ate surfactant (primary candidate) and decide on scaleup (PPD) 8B PPB spk 7/29/81 00Q036 SPR001404 EID715275