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.

Crafting and Analyzing Multi-Structured Aramid Materials and Their Pyrolytic Transformations: A Comprehensive Exploration

“…In our previous research [41][42][43][44], we successfully fabricated porous m-aramids with various cellular morphologies by incorporating a porosity promoter polymer in the casting process. The objective of our current study was to produce porous aramids using high percentages of cellulose acetate (CA) (50% and 100% relative to the aramid) and investigate whether their pyrolysis yields conductive materials while preserving the cellular structure.…”

“…After the initial region, the porosity gradient was controlled by incorporating cellulose acetate as a porosity promoter. In previous studies, we have examined various porosity promoters, such as ionic liquids [41,43,44], boron nitride [47], and different polymers [42], including polyvinyl alcohol (PVA), poly(2-ethyl-2-oxazoline) (PEOx), and cellulose polyacetate (CA). For this work, we have chosen CA, as it allows for excellent control of porosity and is also cost-effective.…”

“…We have pioneered the production of controlled porosity aromatic polyamides as conventional materials (not gradient porous materials), ranging from nanoporous to microporous structures, and using standard solution casting procedures. Furthermore, we have developed a scalable and cost-effective preparation procedure utilizing porosity promoter polymers [41][42][43]. Currently, we are introducing the production of gradient porous aramids (GP-Aramids) and gradient porous pyrolyzed aramids (GP-Pyramids), opening the door to their future applications.…”

Capillary Rise: A Simple Tool for Simultaneous Determination of Porosity and Thickness of Thin Silica Coatings

“…These synthetically developed porous materials include fabrics, paper materials, filters, foams, ceramics, composites and powder coatings. Generally, porous materials play crucial roles in many fields and technology due to their unique properties, especially their low density [1], large surface area [2] and a range of novel physical, mechanical, thermal, electrical and acoustic properties [3]. These unique properties have afforded their application in catalysis [4,5], sorption of pollutants from aqueous solutions, water treatment [6], sound absorption [7], fire resistance/thermal insulators [8], controlled wetting [9], oil spill clean-up [10], drug delivery [11] and orthopedic applications, etc.…”