Synthesis, Characterization, and Gas Permeation Properties

Amino Acid Esters of Hydroxypropyl Cellulose
glycine, alanine, and lysine derivatized polymers. Moreover, elemental analysis was
carried out and the %N content of the polymers was exploited for the sake of
confirmation of the exact degree of amino acid incorporation (DSEst).
Further evidence was acquired from the presence of the peaks characteristic of
the carbonyl group of an ester (1755–1750 cm -1 ) in the IR spectra of the amino
acid-functionalized polymers (2a–f). The IR spectrum of 1 (Figure 2) displayed a
broad band attributable to the hydroxy groups of HPC (3600–3200 cm -1 ), which did
not disappear upon derivatization as the NH bonds corresponding to the amino acid
moiety absorb IR radiation in the same wavenumber region. Moreover, the peaks at
1713–1705 cm -1 and 1521–1505 cm -1 should correspond to the C=O stretching and
NH-bending of the carbamate linkages present in the form of protected amino termini
of the resulting polymers.
Figure 2. FTIR spectra of polymers 1 and 2a–f.
The molecular weights of the starting (1) as well as derivatized polymers
(2a–f) were determined by the gel permeation chromatography and the data are listed
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