Synthesis, Characterization, and Gas Permeation Properties

General Introduction
incorporation of perfluorobenzoyl group (R = CF3CO, 3a; C2F5CO, 3b; C3F7CO, 3c;
C7F15CO, 3d; C6F5CO, 3e). The substitution of perfluoroacyl pendants had an
evident influence on various properties of ethyl cellulose, and the resulting polymers
(3a–e) were more soluble in polar aprotic and nonpolar solvents while the completely
acylated derivatives were soluble in fluorinated solvents as well. Perfluoroacylation
resulted in the enhanced hydrophobicity and derivatized polymers exhibited higher
contact angle with water on the surface. Trifluoroethanoyl derivative (3a) displayed
the highest glass transition temperature which decreased with the increment in the
length of the alkyl chain. Furthermore, the gas permeability of perfluoroalkanoylated
derivatives was 2–3 times higher than that of ethyl cellulose by the virtue of the
augmentation in the gas diffusion coefficients emanating from the repulsion between
highly electronegative fluorine atoms thus leading to the enhanced FFV of the polymer
matrices.
H/EtO
R
OEt
=
O
O
OEt/H
+
Perfluoroacylation
agent
Chapter 3 is concerned with a successful merger of two unique families of
macromolecular architectures delineating 3d a pathway to dendronized 3e cellulose
derivatives and elucidates the effect of amidoimide dendritic substituents on the
solubility behavior, thermal characteristics, and gas permeation properties of the
dendron-functionalized polymers. G1 and G2 of amidoimide dendrons with
branched alkyl periphery and focal carboxyl moiety were synthesized via a convergent
19
in THF
Imidazole, r.t., 24 h
R/EtO
1 n
3
F
F
F
C
F
OEt
3a 3b 3c
F
F
F
F
O
F
F
F
F
F
F
F
F
F
F
F
O
F
F
F
F
O
F
F
F
F F
F
O
F
F
F
F
F
F
O
O
OEt/R
O
n