Abstract: The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 11% by weight, preferably from 4.5 to 8% by weight, as measured on approximately 40.mu. thick symmetrical films at room temperature and at 65% relative air humidity, a throughflow of 130 to 200 l/m.sup.2 d for a desalination level of 94.6 to 99.5% and consisting of an aromatic heterocycle-containing copolyamide with a relative viscosity of .gtoreq.1.4, as measured on a 0.5% N-methyl pyrrolidone solution at a temperature of 20.degree. C.

Abstract: The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 10% by weight preferably from 4.5 to 8% by weight as measured on approximately 40.mu. thick symmetrical films at room temperature and 65% relative air humidity, with a throughflow of at least 80 1/m.sup.2 d for a desalination level of at least 85% and consisting of a fully aromatic copolyamide with a relative viscosity of .gtoreq.1,4, as measured on a 0.5% N-methyl pyrrolidone solution at a temperature of 20.degree. C.

Abstract: The invention relates to antistatic polyamide compositions comprising a polyamide and as an antistatic agent from 0.1 to 20%, preferably from 1.5 to 15%, by weight based on the total weight of the composition of urethanes with ether groups. The urethanes with ether groups are stable in melts of aliphatic polyamides for prolonged periods at temperatures of up to about 300.degree. C. and filaments and fibers of such polyamides or woven fabrics, knitted fabrics, non-woven or pile fabrics produced from these filaments or fibers show outstanding antistatic properties.