Gas-transport properties of novel composites based on addition poly(3-trimethylsilyltricyclononene-7) and substituted cyclodextrines

In this work we report the preparation and properties of composite materials for gas separation membranes based on highly permeable addition poly(3-trimethylsilyltricyclononene-7) (PTCNSi1) as a matrix and substituted cyclodextrines (CD) as fillers. CD studied had different structure and this allowed us to explore correlations between the structure of the fillers and gas permeation parameters of the resulting compositions. Namely -, -, and -cyclodextrines with Me- or Me3Si-substituents were synthesized and the composites containing them were prepared. Permeability coefficients of the obtained composites were determined for He, H-2, O-2, N-2, CO2, CH4. It was found that the introduction of cyclodextrines with bulky Me3Si-groups rather weakly influenced the permeability coefficients for He and H-2, while for other gases a marked decrease in permeability was observed. On the other hand, in the case of the composites containing Me-substituted CD decreases in permeability were observed for all the studied gases. The changes of gas permeability dramatically depend on the size of gas molecules and this results in an increase in selectivities for some gas pairs. Thus, introduction of -CD with Me-groups resulted in an increase in selectivity (H-2/N-2) from 5.2 for pure polymer to 9.1. The increase in CD content in a composite gave an extra growth of selectivities. BET, TEM, WAXD, positron annihilation data (free volume) and mechanical properties of the composites were also studied and discussed. POLYM. COMPOS., 36:1029-1038, 2015. (c) 2015 Society of Plastics Engineers