Synthesis, Characterization, and Gas Permeation Properties

Amino Acid Esters of Hydroxypropyl Cellulose
substituents augments the chain flexibility and thus ensues the reduced Tg. 10 In
previous studies concerning the derivatization of other organosoluble cellulosics like
ethyl cellulose and cellulose acetate, the incorporation of bulky nonpolar substituents
has been reported to lead to the decline in the glass transition temperature of the
polymers. 8b,c However, the present series of polymers (2a–f) is characterized by the
presence of polar amino and ester linkages along with spherical peripheries, probably
the former being more dominant in the determination of Tg. Hence, the substitution
of small hydroxy groups by bulkier aminoalkanoyl functionalities has led to the
increment in Tg resulting in the transition from rubbery (1) to glassy (2a–f) polymeric
materials.
Figure 4. DSC thermograms of polymers 1 and 2a–f (under N2, second scan) a .
a The lower portion delineates the DSC trace for 2f (derivative with the lowest T0
value), indicating the absence of the commencement of weight loss under N2 until
188 °C.
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