| abstract |
Ultraporous and microporous polymer membranes cast fromnmetastable dispersions are significantly improved bynlimiting the time of environmental exposure to less thannabout 0.5, preferably less than 0.25 seconds, betweenncasting and quenching, and reducing the casting temperaturesnabout 10 to about 20°C lower than the usual prior artnvalues. The resulting membranes have far less debrisnentrained in the membrane, far more consistent and uniformnpore sizes, a substantially greater number of skin pores,nand greatly increased flow rates for any given porendiameter. |