Preparation of low‐density high‐performance porous aramid films using porosity promoter polymers

Abstract Low‐density porous aramid films using inexpensive and widely available polymers as porosity promoters, that is, polyvinyl alcohol (PVA), poly(2‐ethyl‐2‐oxazoline) (PEOx), and cellulose polyacetate (CA) were fabricated. Porous poly ( m ‐phenylene isophthalamide) films were obtained by the standard casting procedure using mixtures of the aramid with either PVA, PEOx, or CA, followed by the removal of the porosity promoter polymers by immersing them in water or acetone. As a result, films with up to a 65% density reduction with pore sizes ranging from 0.02 to 10 μm and up to 30% increment in Young's modulus were obtained. In addition, the morphology of the films was homogeneous and was controlled by the proportion and nature of the porosity promoter polymer. The density reduction of materials plays a significant role in energy crises and the need for fuel reduction. This study revealed that it is possible to prepare low‐density porous aramid films inexpensively without impairing their outstanding performance by using PVA in the casting procedure as a porosity promoter polymer.