Increasing the Permeability of Carbon Dioxide and Nitrogen Gases Through a Polymer Membrane Consisting of a Modified Polyether Block Amide and Experimental Design

Newly, Pebax polymer (pure and composite polyether block amide) has been extensively applied for CO₂ elimination from air contaminants. The Pebax involves of polyamide (PA) and stretchy polyether (PEO) portions, which can suggest excellent solubility as well as bulk-free fractional volume for CO₂ permeation. In the present work, the polymeric nanocomposite membranes (Pebax/PEG/NCS) were synthesized by adding different amount of nanochitosan particles (NCS) and polyethylene glycol (PEG) to the Pebax with applying Taguchi’s experimental design with Minitab software as well as using thermal phase separation method. The input variables to the software included 4 factors at 4 levels, namely wt% of PEG, wt% of NCS, temperature (°C), and pressure (bar) in the ranges of (0, 20, 30, 40), (0, 10, 20, 30), (30, 35, 40, 45), and (4, 6, 8, 10), respectively. The Taguchi method yielded 16 optimal test arrays, each with different conditions. The morphology and structure of NCS and synthesized membranes, Pebax/PEG/NCS, were studied using infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) tests. Their thermal properties were analyzed using thermal gravity analysis (TGA) and differential scanning calorimetry (DSC) tests. The effect of NCS amount, polymer concentration, temperature, and pressure on the performance of the Pebax/PEG/NCS was then studied. Lastly, the permeability of the constructed membranes was measured using the constant pressure-variable volume method. The first result of the present work indicated that the permeability of CO₂ was higher than N₂ gas due to its non-polarity and determinability. The second result obtained is that the increase of NCS increases the permeability and selectivity of N₂ and CO₂ gases. The third result showed that in the gas permeation test in Pebax/PEG/NCS, the maximum permeability of CO₂ was from the B15 test with a value of 281.111 barrer, and the maximum permeability for N₂ gas from the B14 has a permeability of 17.477 barrer at a temperature of 35 °C and a pressure of 10 bar. The obtained results are in good agreement with the literature.