Gas separation using Knudsen and surface diffusion I: Preparation of epoxy/porous SiO2 composite

• Epoxy/porous SiO2 composites were prepared from epoxy and porous SiO2.
• Appropriate liquid was filled into porous SiO2 to prevent epoxy resin invasion into the pore.
• These composites have pores of only about 20 nm.
• Composites containing 40–70% porous SiO2 exhibited gas permeability.

Epoxy/porous SiO2 was prepared using casting. First, the SiO2 pores were filled with the liquid. Then, the present porous SiO2 mixed with epoxy resin and hardener. The liquid composition was decided by the static contact angle measurement, and 90% H2O/10% EtOH was the optimum liquid for this study. The sample prepared using this liquid mainly has approximately 20 nm pores in porous SiO2. In contrast, the epoxy/porous SiO2 composite prepared with EtOH was not porous. Furthermore, a composite prepared with ion-exchanged purified water had pores corresponding to porous SiO2 and unfavorable pores. Gas permeation tests of the samples were conducted. Samples containing less than 40% porous SiO2 showed no gas permeation, indicating that these samples did not have through holes. Samples containing 40–70% porous SiO2 showed gas permeability. The gas mainly passed through the porous SiO2. The epoxy resin was insufficient for preparation of samples with more porous SiO2 contents.

Epoxy/porous SiO2 composites were prepared from epoxy and porous SiO2 previously filled by the appropriate liquid. The obtained composites have about 20 nm pores.Figure optionsDownload as PowerPoint slide