Fourier transform Infrared spectroscopy results show no
differences between the spectra of the three extracted poly-
mers. Carbonyl and ester groups at 1726 and 1330–1050 cm1
, respectively, and methyl group at 1390 cm1
are shown in the three spectra corresponding to the main
bands of PHB.
1
H NMR spectra show the presence of
three groups of signals, characteristics of the homopoly-
mer PHB (Fig. 3): a doublet at 129 ppm which is attrib-
uted to the methyl group coupled with one proton (signal
3, Fig. 3), a doublet of quadruplet at 257 ppm which is
attributed to a methylene group adjacent to an asymmetric
carbon atom bearing a single proton (signal 2, Fig. 3) and
a multiplet at 527 ppm characteristic of the methylene
group (signals 1, Fig. 3). Two other signals are also
observed: one at 370 ppm which is due to the methylene
group at the end of the chain (signals 4, Fig. 3) and
another one at 725 ppm which is attributed to chloro-
form (signals CHCl3, Fig. 3) (Jan et al. 1996).