A porous polymeric membrane formed from a blend of a polymeric membrane forming
material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity
modifying agent adapted to modify the surface active properties of the porous polymeric
membrane. The reactivity modifying agent is preferably a linear polymeric anhydride,
such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications
include modification of the hydrophilicity/hydrophobicity balance of the membrane,
or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide
layer. Such modified membranes have use as reverse osmosis membranes.
