Synthesis, Characterization, and Gas Permeation Properties

t-Butylcarbamates of Cellulose Derivatives
Solubility and Thermal Properties of Polymers. The solubility properties
of ethyl cellulose (1 and 2), cellulose acetate (3 and 4), and their carbamate derivatives
(1a–4a) are described in Table 2. 1 and 2 are soluble in polar protic solvents such as
methanol and highly polar aprotic solvents like DMF and DMSO, and the same
tendency was retained upon carbamoylation. The solubility behavior of the
carbamate derivatives of ethyl cellulose, 1a and 2a, in THF and CHCl3 was the same
as that of the starting polymers, and only the two points of difference were the
complete solubility of 1a in polar aprotic solvent acetone (1 is partly soluble) and that
of 2a in toluene (2 is partly soluble). However, the solubility characteristics of
cellulose acetate (3 and 4) got significantly tuned as a result of substitution of small
hydroxy groups with polar carbamate linkages possessing a bulky alkyl periphery.
For instance, 3 was insoluble in methanol and toluene, and partly soluble in CHCl3,
whereas 3a was observed to be completely soluble in methanol due to the polar nature
of the carbamate group, and in CHCl3 and toluene owing to the presence of the bulky
Figure 5. TGA curves of polymers 1, 2, 1a, and 2a (in air, heating rate 10 ºC
min -1 ).
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