a filter medium includes at least one first fiber made from a first polymer selected for the chemical and high temperature stability properties needed for a particular operation and at least one second fiber made from a second polymer having a relatively higher glass transition temperature than the first polymer . the filter medium has a higher glass transition temperature than the first fiber , allowing the filtering media to withstand the temperature requirements of the operation , while retaining the chemical resistance of the first fiber . this is particularly useful for pleated filters that are highly temperature dependent , and in industrial baghouse operations where temperatures often exceed the operating range of the first polymers . a method for making the filter medium is also disclosed .