(65q) Synthesis and Characterization of Sulfonated Poly(styrene-isobutylene-styrene) for Chemical and Biological Protective Clothing

Poly(styrene-isobutylene-styrene) (SIBS) of 15% weight fraction polystyrene and 100k number average molecular weight (Mn) was sulfonated and functionalized to create ion selective polymer membranes for chemical and biological protective clothing among other applications. Highly selective polymer-metal nanocomposite membranes were created by ion exchange substitution with +2 cations, Mg⁺², Ca⁺² and Ba⁺². Selectivity experiments were performed using Dimethyl Methyl Phosphonate (DMMP), a molecule similar to the chemical warfare agent Sarin. The highest Water/DMMP selectivity in the gas phase and the least water absorption percentage was obtained with Ba⁺². Polymer membrane properties were evaluated by different characterization techniques including Fourier transform infrared spectroscopy, thermogravimetric analysis, and small angle X-ray scattering. Results from these experiments show significant differences between the sulfonated and ion substituted polymers that can explain the variations in selectivity and water swelling behavior.