than 40 of their initial water flux during sterilizing steam treatment this is a surprising result in view of the fact that the following table showing data with the same polymer cast into a dmf water coagulant solution loses almost all flux as a result of autoclaving table 2______________________________________ultrafiltration coefficient ufc of an heacopolymers before and after autoclaving water ufc ml hr m sup 2 mm hg sample in dmf before autoclave after autoclave______________________________________nbp 44a 40 96 96 4 32nbp 44b 50 67 68 1 48nbp 44c 60 78 72 0 80nbp 44e 80 81 60 0 40nbp 44f 100 103 68 2 08______________________________________ concentration 18 w w in dmf this is further confirmed by the results of table 3 showing that casting the same polymer dissolved in nmp into a mixture of nmp water also leads to the loss of flux following autoclaving table 3______________________________________ultrafiltration coefficient ufc of an heacopolymers before and after autoclaving water ufc ml hr m sup 2 mm hg sample in nmp before autoclave after autoclave______________________________________nbp 45a 40 172 8 74 4nbp 45b 50 259 2 81 5nbp 45c 60 241 4 8 4nbp 45d 70 302 4 31 9nbp 45e 80 323 0 59 3______________________________________ concentration 15 w w in nmp the use of an i proh water coagulation bath when combined with film formation of.