Development of nanocomposite materials for gas separation membranes

The objective of this study is to improve the compatibility of nanoparticles in composite materials. This was achieved by developing a method in which an inorganic precursor contained in a stable water/oil (W/O) emulsion was mixed with a polymer solution containing a second inorganic precursor. Inorganic polymerization occurred in the aqueous domain of the W/O emulsion. The in-situ synthesis of the precursor was performed in order to enhance the nanoscale compatibility between the inorganic material and polymer. This technique produced materials which we have named: emulsion polymerized mixed matrix (EPMM) materials. A series of poly (2,6-dimethyl-1,4-phenylene oxide) (PPO)-based organic-inorganic membranes were prepared by employing this method. A W/O emulsion containing aluminium hydroxonitrate was added to a PPO solution containing tetraethyl orthosilicate (TEOS). Droplet sizes in the W/O emulsions, observed by dynamic light scattering (DLS) ranged from 254 to 344 nm. Scanning electron micrography (SEM), electron diffractive X-Ray (EDX), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and gas permeation and separation measurements were carried out to characterize the EPMM membranes. SEM indicated the presence of inorganic particles in the PPO matrix, and EDX measurements showed the embedded particles contained Al and Si elements, which confirmed the hydrolysis and condensation of TEOS with aluminium hydroxonitrate. DSC analysis showed a decrease in the glass transition of the EPMM membranes with increasing of TEOS loading. The fractional free volume of the EPMM membranes was predicted through the measurement of the heat capacity jump at the glass transition temperature. The integrity of the EPMM membranes was confirmed in gas separation test with air, in which the ideal selectivity for O2/N2 was observed to be as high as 4.56