Document a48g1a8yyrGNzVkdbXqo244RX

4R.-.20 3-R REV. 3-77 CSTUUSHCD1102 E. I. du P ont de N emours & Co m pany INCORFOIUTED Spruance Plant P.O. Box 27001 Richmond, Virginia 23261 TEXTILE FIBERS DEPARTMENT CC: \>LJ^S*rtIvan Hollberg J. L. McDaniel J. H. Fisher R. F. Janis, Jr. J. P. Yuk sQeziC-IC5 7 September 30, 1981 SECTION I - TEFLON A. FC-143 In Teflon Products - S. S. Shelburne Objective: Determine levels of FC-143 in the Teflon process, the conditions and mechanism for removal of and the identification of byproducts of thermal treatment. Status: Analysis of thermal treatment of FC-143 sodium salt is complete. The results show that a FC-143 sodium salt present on Teflon I and T products can be removed by thermal treatment at temperatures of 175C or higher. In the presence of the Triton X100 emulsifier, the major reaction is decarboxylation'(90%) with carbon dioxide and perfluoroheptamonohydride gases as the byproducts. Althougn thermal treat ment can effectively remove the FC-143, it is not the prime candidate because of possible deleterious effects on product performance. ARL (Mokhtar) has shown that Teflon I and T yarns heated at 175C for 30 minutes or 200C for 10 minutes no longer have any extractable FC-143. IR scans of off-gas from y a m s heated at 200C and 250C confirm the presence of a fluorocarbon gas by the absorption peak at 1250 cm~l. The presence of the CO2 peak at 2350 cm"^- confirms CO2 evolution, i.e., the FC is decarboxylating. There is no carboxyl peak present which would show that the FC-143 is evaporating. Further study of the gases evolved at 200C from Triton X100/FC-143 sodium salt mixtures in a 5:1 ratio, show the presence of a C-H. absorption peak at 3010 cm"*-. This shows that the fluorocarbon gas evolved on decarboxylation is the perfluoromonohydride. There is no evidence of an olefine (C = C, 1790 cm~^) which was a possible decomposition product. (Figure I-SSS). The Triton X-1UU supplies the hydrogen necessary to form the hydride. Analysis of the completeness of the decarboxylation was made by passing known amounts of off-gas through a Draeger tube. The tube, specific for CO2 , uses a color change to volumetrically measure the CO2 evolved. The amount was 90 - 10% of the theoretical, showing that no other major reaction occurs during thermal treatment. The new N i ^ electron captnre detector has been installed on the HP5880 and is in the process of being checked out. This will be used for blood analysis and for rechecks of area air samples. SSS/dsa B E T T E R T H IN G S FOR B E T T E R LIVING . . THROUGH c h f m i c t o v 000081 SPR001330 EID715206 000082 SPR001331 EID715207