FTIR spectroscopy has been widely used to investigate the specific interactions between polymers. Therefore, in order to confirm
the intermolecular interactions between HLS and PVA, FTIR spectra of pure PVA and subtraction spectra obtained by subtracting
the spectrum of pure HLS from the blends were illustrated in Fig. 4.
The subtractions are achieved until 1515 cm−1 band of HLS, which
is the only absorption band without any superposition of those due
to PVA, is smoothly canceled out. This method has been widely adopted for analyzing the interactions of components in polymer
blends .