Synthesis, Characterization, and Gas Permeation Properties

General Introduction
Keeping in view, the commercial, environmental, and energy-related
significance of membrane based separation to fulfill the desire for sustainable
chemical processing and to meet the requisites of good separation performance
together with low cost and durability, author has envisioned the development of gas
separation membranes based on the most sustainable and promising biopolymer of
21st century.
Ethyl cellulose and cellulose acetate have been the subject of gas separation
membranes for several years, however, no considerable attempts have been made to
effect the derivatization of these low cost membrane-forming cellulosics or to
elucidate the role of various pendants in the transformation of architectural
characteristics and thus the gas transport performance of new functionalized
derivatives. The present treatise narrates the profound impact of the incorporation of
a number of pendants of varied chemical nature on the gas permeation parameters of
ethyl cellulose and cellulose acetate. The history of polymeric gas separation
membranes celebrates the presence of spherical silyl groups to bestow the acetylenic
polymers with high gas permeability thus new silylated derivatives of ethyl cellulose
were fabricated into free-standing membranes. The author reasoned the increased
diffusion coefficients leading to higher gas permeability to emanate from the enhanced
local mobility despite the decrement in the solubility coefficients on account of the
attenuated fractional free volume. Owing to the high electronegativity of fluorine
atoms, fluorinated polymers are known to display the unique characteristics of high
gas permeability with reasonable permselectivity. The fluorinated derivatives of
ethyl cellulose are inferred to possess higher gas diffusion and solubility thus
improved gas permeability due to the enhanced FFV ensuing from the repulsive
interaction between fluorine atoms, on the other hand, high chain stiffness helped
preventing the expected loss of permselectivity. Moreover, polar functionalities such
as poly(amidoamine) dendrimers exploited in the form of composite or immobilized
liquid membranes have recently been revealed to offer excellent CO2 separation
capability. Therefore, amidoimide dendritic pendants were integrated to ethyl
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