Hybrid Organic-Inorganic Polyimide-SiO2-TiO2 Nanocomposite Gas Separation Membranes

Hybrid Organic-Inorganic
Polyimide-SiO₂-TiO₂ Nanocomposite Gas Separation
Membranes

Polymers are highly attractive for many industrial
separation efforts due to their low cost, processing flexibility, and desired
physical properties. Despite these advantages, an 'upper bound'
relationship exists that poses a challenge with improving the selectivity and permeability of
polymer membranes. In addition, gas selectivity for polymeric membranes is
typically lower than for inorganic membranes. These challenges can be overcome
by utilizing [6F-DABA]-[SiO₂-TiO₂] hybrid
organic-inorganic nanocomposite membranes, which offer new material
possibilities. This is possible due to synergistically combining the desirable
physical properties of organic polymers, and the separation characteristics of
an inorganic material to create a hybrid membrane. The [6F-DABA]-[SiO₂-TiO₂]
nanocomposite membranes in this research had a higher concentration of benzoic
acid along the polyimide's backbone. Compared to pure polyimides, this demonstrated significant improvements
in gas separation. However, the presence of [SiO₂] reduced both the
membrane's permeability and selectivity. In addition, all inorganic
nanoparticles reduced the permeability of the membrane. 

In this work, it has been revealed that nanocomposite
membranes with designed compositions have much better gas separation
performance than pure polyimides. The significance of this work is that the
study of [6F-DABA]-[SiO₂-TiO₂} nanocomposite membranes
will open a new avenue for the exploration of hybrid inorganic-organic
materials for use in gas separation based upon controlled mixing of ceramic
[SiO2-TiO2] nanodomains via sol-gel chemistry.