Synthesis and characterization of novel polyimide/clay nanocomposites and processing, properties and applications

Abstract

Mixed matrix membranes (MMMs) with cloisite® 15A clay in polyimide (PI) matrix were matured for gas separation applications. The inorganic cations of clay were replaced with cloisite® 15A as modifier. The altered cloisite® 15A clay showed excellent dispersion in the polymer matrix as evident from TEM micrographs. Uniform dispersion of cloisite® 15A clay improved the thermal properties of MMMs. The synthesized membranes were characterized by utilizing various spectrometer including FE-SEM, XRD, DTG, and TEM. FE-SEM results showed that at 3 wt% of clay15A, the fillers were dispersed homogeneously within the PI polymer matrix. The tensile properties of PI/cloisite® 15A clay nanocomposites increased gradually according to clay content increasing. The impact strength of nanocomposites was not altered until 3 wt% of clay and decreased at 5 wt% clay loading. Layered silicate cloisite® 15A clay particle plays major several key roles in determining the gas permeation behavior of the hybrid membrane. It was no surprise that the gas permeation flux was decreasing with the addition of layered silicate cloisite® 15A clay into the PI matrix. However, it was interesting to point that the pure gas selectivity was seen to be increased by decreasing the filler loading. At 1 wt% clay loading, cloisite® 15A clay MMMs showed an increase of 55% in CO2/CH4 ideal selectivity over pristine PI membrane.