Membrane Gas Separation

12.5
Conclusions and Future Aspects 
It is accepted that in the last 20 years there were no signifi cant improvements in CO 
2
-
separation membranes; rather, improvement or development of new membrane material 
was in laboratory scale but not on large scale. It seems that performance of polymeric 
membranes has reached a maximum level and it is diffi cult to achieve signifi cant improve-
ments. On the one side, the membrane technology (e.g. modules, engineering) is being 
daily improved, but on the other side, the lack of new materials with higher performance 
does not allow further progress. Actually, the cardo - polyimide membrane developed by 
RITE institute could be the best for CO 
2
separation, but it is still in consideration for 
large - scale applications [95] . 

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Tailoring Polymeric Membrane Based on Segmented Block Copolymers
249
From results discussed above, one can see that an improvement of existing membrane 
material with high performance can be cheap and easy to scale - up. 
Tailor - made polymeric membranes such as poly(ethylene(oxide) - poly(butylene tereph-
thalate), a multi - 
block copolymer discussed in this chapter, is controlled by fraction 
of PEO phase and its molecular mass, thus allowing its structural manipulation. The addi-
tion of a plasticizer and fi ller which can simultaneously enhance the solubility and 
diffusivity selectivity of CO 
2
over other gases will produce materials with the desired 
transport properties, thereby the study of block copolymers, its assembly and its nanos-
tructures seem to be the way that will enable to fi nd a superior membrane material. 
Following the proposed strategy (simultaneous increase of solubility and diffusivity by 
increasing the free volume in rubbery - like membranes), membranes with better perform-
ance were recently reported, hence we strongly recommend to the readers the references 
[96 – 98] .