Imide Containing Polymers as Promising Filtration Nonwovens

Abstract

Nonwoven materials are fashioned from polyimide (PI) and its copolymer derivative (urethane–imide) (CPUI) through the formation of electrical fibers, referred to as electrospinning (ES). Diaminobiphenyl ether (DABPE) and pyromellitic anhydride (PMA) are chosen as monomers in the synthesis of polyimide. Diamine dianhydride and toluene di-isocyanate (TDI) are used in the synthesis of copoly(urethaneimide), as is polycaprolactone (M_n = 2000). A nonwoven polyimide material is obtained from an aqueous–ethanolic solution of the triethylammonium salt of polyamide acid (SPAA) with subsequent thermal imidization of the nonwoven prepolymer at 250°C. A nonwoven material based on SPAA is obtained from a solution of copoly(urethaneamidoacid) in dimethyformamide (DMF) using a catalytic mixture consisting of triethylamine and acetic anhydride. Optimum conditions are selected for the formation of nonwoven fibers in electrospinning. The chemical structure of nonwovens is confirmed via IR spectroscopy. The morphology of the microstructure of nonwovens is studied by means of scanning electron microscopy (SEM). The thermal and mechanical properties of the obtained nonwovens are determined using TGA, DSC, and DMA, and their deformation and strength characteristics are determined. Membrane filtration properties of the obtained nonwovens are studied. It is concluded that nonwovens can be used as membranes that operate in nonaqueous organic media.