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In this work, Polydimethyl siloxane/polysulfone (PDMS/PSF) membrane was developed by dip coating of developed PSF membrane. Developed membranes were characterized in terms of thermal analysis, glass transition temperature, and membrane morphology. Performances of the developed membranes were tested using gas permeation equipment within the pressure range of 2-10 bar. To study the water swelling in membrane, developed membranes were soaked in distilled water for 5 minutes. Gas permeation in membrane was investigated before and after swelling. Based on the results, increase in CO 2 permeance was observed due to plasticization in membrane before swelling. However, CO 2 permeance decreased after swelling in membrane. Swelling affected the separation performance of membrane by decreasing its permeance. While, CO 2 /CH 4 selectivity has increased after membrane swelled. Hence, swelling resulted in membrane contraction, which contributed to the increase of selectivity. Pure polysulfone membrane exhibited higher degree of swelling, whereas PDMS/PSF membranes demonstrated substantial high resistance toward swelling. Based on swelling degree of PDMS/PSF composite membrane, this membrane can be considered as a potential water (swelling) resistant polymeric membrane for CO 2 /CH 4 separation. [ABSTRACT FROM AUTHOR]

Polymeric membranes demonstrate the fastest emerging field in membrane gas separation since it has huge reproducibility for large scale production and low cost fabrication. To date, many research works have emerged to propose different polymeric materials for membrane synthesis and fabrication in order to enhance gas separation performance. It has been suggested that the underlying factor that distinguishes the difference in separation efficiency among varying polymer is the amount of free volume formed throughout the polymeric matrix. Therefore, in current work, through adaptation of atomistic models by a combination of molecular dynamics and Monte Carlo or commonly known as the Cavity Energetic Sizing Algorithm (CESA), the cavity size distributions of several commonly adapted polymeric membranes for gas separation have been determined. The accuracy of the simulated molecular structure has been verified by comparing the simulated and measured experimental density. It is found from the study that that the CESA algorithm is capable of capturing the free volume distribution within the polymeric matrix, with the higher free volume polymeric membrane inheriting higher average cavity size [PTMSP (10.30A) >PPO (4.86A) >Matrimid® 5218 (4.01A) >PSF (3.25A)]. In addition, the higher free volume polymers, which exhibit shift towards the larger cavity sizes, also reveal higher gas permeability for gas molecules. The sieving capability of the polymer is also demonstrated to be correlated with the kinetic diameter of the gas penetrants as compared to the cavity size. In future work, the methodology is proposed to be employed as a preliminary step to predict polymeric membrane morphology in order to evaluate the feasibility of any polymers before being applied in gas separation. [ABSTRACT FROM AUTHOR]

In this work, the rheology of a solvent which consisted of monoethanolamine (MEA) as well as water and n-methyl-2-pyrrolidone (NMP) (weight ratio 20:40:40) was studied at gauge pressure up to 5 MPa and temperature range from 303.15 to 333.15 K. The flow chart showed positive linear relationship between shear stress and shear rate for the solvent at all temperature and pressure conditions tested. This trend was consistent with the behaviour of a Newtonian fluid. The dynamic viscosity of MEA-NMP hybrid solvent at temperature from 303.15 to 333.15 K and gauge pressure from (0.1 to 5) MPa was calculated from the rheology data measured. [ABSTRACT FROM AUTHOR]