Novel hybrid membranes by incorporating SiO2 nanoparticles using in situ microemulsion polymerization: preparation, characterization and enhancement in the performance for CO2/N2

Abstract

SiO₂ nanoparticles were synthesized in a water-in-oil microemulsion using a triblock copolymer as the surfactant and methyl methacrylate as the oil phase. Then, SiO₂/poly(methyl methacrylate) (PMMA) hybrid membranes were prepared by in situ microemulsion polymerization. The separation of CO₂/N₂ gas mixtures was studied using these novel membranes. Both the gas permeability and separation performance of the hybrid membranes first increased and then decreased with SiO₂ content. When the SiO₂ content was 4.0 wt%, the CO₂ permeability and permeability selectivity of the membranes for CO₂/N₂ gas mixtures were both at a maximum. For comparison, two commercially available SiO₂ nanoparticle materials were also used to synthesize SiO₂/PMMA membranes by solution polymerization. The particle size of SiO₂ in the microemulsion was close to the two commercially available SiO₂ nanoparticle materials. The SiO₂ nanoparticles formed in the microemulsion were distributed more homogeneously in the membranes than the commercially available nanoparticles because of the protection by the water droplets. Moreover, the SiO₂ nanoparticles formed in the water droplets and reverse microemulsion had a strong polar surface. Therefore, the SiO₂/PMMA hybrid membrane formed by the in situ microemulsion polymerization had better performance than the hybrid membranes made with commercially available SiO₂ nanoparticles.