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Development of Nanocomposite Membranes Containing Modified Si Nanoparticles in PEBAX-2533 as a Block Copolymer and 6FDA-Durene Diamine as a Glassy Polymer

Nafisi, Vajiheh, Hägg, May-Britt
ACS Applied Materials & Interfaces 2014 v.6 no.18 pp. 15643-15652
carbon dioxide, composite polymers, gases, methane, nanocomposites, nanoparticles, nitrogen, oxygen, permeability, silicon, superoxide anion, transmission electron microscopy
Nanocomposite membranes of modified Si nanoparticles as inorganic filler in two different polymers from two different categories were developed. Synthesized 6FDA-durene diamine as a glassy polymer and PEBAX-2533 as a block copolymer were used as the polymer matrix to develop the nanocomposite membranes of modified Si nanoparticles in polymer matrix. The scanning transmission electron microscopy (STEM) results showed nice nano size dispersion of inorganic nanofillers in the polymer matrix in both cases. Pure gas permeation for the gases CO₂, CH₄, N₂, and O₂ and mixed gas of CO₂–N₂ was carried out at 2 and 6 bar for single gas and 2.6 bar for mixed gas using the developed nanocomposite membranes. The loading of inorganic fillers in the PEBAX-2533 polymer matrix resulted in a dramatic increase in gas permeability for all tested gases, while a decrease was observed for CO₂/N₂ and CO₂/CH₄ selectivities with small amounts of loading of filler. With higher loading of inorganic filler, the selectivity did not change, which is probably due to the formation of nanogap around the nanoparticles in the polymer matrix. The dispersion of the nanoparticle inorganic fillers in 6FDA-durene polymer matrix caused an increase on the fractional free volume of the polymer matrix due to the disruption of the polymer chain in the presence of the inorganic fillers. Hence, this disruption resulted in an increase of gas permeability for both single and mixed gases, also with an increase in CO₂/N₂ and CO₂/CH₄ selectivities.