Coating of porous PVC-PEG memebrane with crosslinkable XSBR for O2/N2 and CO2/N2 separation

A polymeric membrane consisting of a supporting membrane composed of a blend of poly(vinyl chloride) (PVC) with poly(ethylene glycol) (PEG), and crosslinkable carboxylated styrene butadiene rubber (XSBR) as a coating layer was prepared in flat sheet form. The supporting membrane was prepared by using a phase inversion technique and the sheets were formed by the casting method. The morphology shown from the cross-section images from a scanning electron microscope (SEM) showed finger-like sponge structures after adding higher contents of PEG with an average molecular weight 400 g/mol. The dense polymeric film was coated with XSBR that acted as the selective layer. The mechanical properties of the membrane were improved after coating with XSBR as was the gas selectivity. The mechanical properties of the membrane were investigated using a dynamic mechanical thermal analyzer (DMTA). The permeation of three single gases from CO2 O2 and N2, through the membranes was measured by a VAC-V1 LabThink gas testing unit and ideal gas selectivity was computed.

XSBR rubber was used to form a skin or selective layer This was attributed to polar gases being induced because XSBR contains a carboxylated group that is a polar structure. At the same time, this membrane does not adsorb non-polar gases such as N2 resulting in a high gas selectivity between CO2/N2.201