Poly(amide-sulfonamide)s 1-4 were synthesized by low-temperature solut
ion polycondensation of diamino monomers 5 and 6 with isophthaloyl chl
oride/terephthaloyl chloride in N,N-dimethylacetamide (DMAc). The poly
mers were adequately characterized for their properties. Membranes wer
e fabricated from PASA 2 under different casting conditions by varying
the casting solution composition, evaporation temperature and evapora
tion time. The reverse osmosis (RO) tests for these membranes were per
formed with 1000 ppm aqueous sodium chloride feeds at 20 to 40 kg cm-2
operating pressure. Membranes showed salt rejections of up to 97.9% a
t a flux of over 11.9 cm per day. The RO performances of the membranes
remained unchanged after treatment with dilute acid, alkali and oxidi
zing agent.