Matrix rigidification

Polyvinyl acetate (PVAc) is another rubbery polymer used in mixed-matrix research. Its flexible nature helps to prevent void formation at the solid-polymer interface. Although it may not have practical industrial applications, PVAc aids in developing proof-of-concept associated with mixed-matrix membranes. Zeolite 4A-PVAc membranes have been proven to enhance membrane selectivity in mixed-matrix membranes with only 15 vol% zeolite " however, the permeability is lower than predicted presumably due to matrix rigidification. The rubbery nature of PVAc allows for more polymer relaxation at the solid-polymer interface as compared to the case with traditional, glassy polymers." ... 

Li, Y., Chung, T.S., Cao, C., and Kulprathipanja, S. (2005) The effects of polymer chain rigidification, zeolite pore size and pore blockage on polyethersul-fone (PES)-zeolite A mixed matrix membranes./. Memhr. Sci., 260, 45-55. 

In our attempt to prepare AB-type helical polymers based on the backbone-rigidification strategy, diacid chlorides 9 were treated with diamine 10. Instead of forming polymers, matrix-assisted laser desorption/ionization (MALDI) spectra indicated that macrocycles 11 were consistently formed in very high yields from repeated reactions (Scheme 2) [66]. 

Li Y, Chung TS, Cao C, Kulprathipanja S. The effect of polymer chain rigidification, zeolite, pore size and pore blockage on polyethersulfone (PES) zeolite a mixed matrix membrane. J Membr Sci 2005 260(l-2) 45-55. 

The new system was called RF -chemistry, for rigidification fixing as we hardened the matrix so as to prevent the molecular migration required for color-formation. 

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