Shaped microporous articles are produced from polyvinylidene fluoride
(PVDF) and nucleating agents using thermally induced phase separation
(TIPS) processes. The shaped microporous article is oriented in at least
one direction at a stretch ratio of at least approximately 1.1 to 1.0.
The shaped article may also comprise a diluent, glyceryl triacetate. The
shaped microporous article may also have the micropores filled with a
sufficient quantity of ion conducting electrolyte to allow the membrane
to function as an ion conductive membrane. The method of making a
microporous article comprises the steps of melt blending polyvinylidene
fluoride, nucleating agent and glyceryl triacetate; forming a shaped
article of the mixture; cooling the shaped article to cause
crystallization of the polyvinylidene fluoride and phase separation of
the polyvinylidene fluoride and glyceryl triacetate; and stretching the
shaped article in at least one direction at a stretch ratio of at least
approximately 1.1 to 1.0.