To further investigate the interact

To further investigate the interaction between lignin and PLA
phases, FTIR was applied to demonstrate the structure difference
among lignin, PLA and their blends. As shown in Fig. 3(a), FTIR
spectra of lignin and Lignin/PLA blends show a strong O-H
stretching absorption around 3494 cm1 and a prominent C-H
stretching absorption around 2938 cm1 and 2840 cm1. The lignin
characteristic peaks appeared at 1608 and 1516 cm1, assigned to
the vibration of aromatic skeleton. The appearance of bands around
1322 and 1212 cm1 represents the C-O stretching of S ring and G ring, respectively [27]. The CeH deformation of methyl and methylene
and C-H stretching absorption of S and G units appeared at
1459 and 1114 cm1, respectively. The carbonyl(C=O) stretching
band of lignin was reflected at 1715 cm1, while that of PLA
appeared at 1756 cm1.When 5 wt.% of PLA was added to lignin, the
C-O peak of PLA was shifted from 1756 to 1760 cm1 due to the
change in the surrounding environment. Besides, the C-O band of
lignin became unobvious compared with that of PLA in Lignin/PLA
blends. The amplified spectrum of C-O stretching region is
depicted in Fig. 3(b). The C-O band of Lignin/PLA blends
was shifted to a lower wavenumber with the increasing content
of PLA, from 1760 cm1 of Lignin/PLA 95/5 blend to 1757 cm1 of