Addition Norbornene Polymer-Based Membrane Materials
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Substituted norbornenes and tricyclononenes can be polymerized according to the addition scheme, that is, via opening of the double bonds of these cycloolefins (Finkelshtein et al. 2011; Yampolskii 2010).
The resulting glassy polymers have very rigid main chains and high glass transition temperatures. The gas permeation parameters of the obtained polymers strongly depend on the substituents in the monomer molecules. Thus, nonsubstituted addition polynorbornene (PNB) is a relatively low-permeability polymer (P(O2) = 11 Barrer), though when substituents are introduced permeability increases markedly (Fig. 1). In particular, methyl-substituted PNB has P(O2) = 89 Barrer, while for the polymer with bulkier, SiMe3 substituent, the permeability is further strongly enhanced (P(O2) = 980 Barrer) (Yampolskii 2010). SiMe3-substituted PNB and poly(tricyclononenes) reveal large free volume according to the positron annihilation lifetime spectroscopy and solubility-controlled selectivity in...