Differentiation by FT-IR of Absorbable Polyesters Used in Production of Surgical Meshes

摘要

The major differences in chemical structure between these three polymers are the methyl group in PL, methylene groups in PG and PD, and ether groups in PD. These differences result in the presence, absence, or shifting of particular bands in the absorption spectra. For instance, PLLA lacks the bands associated with methylene scissoring and symmetric ether stretching. PG lacks asymmetric and symmetric methyl bending, as well as symmetric ether stretching. And PD displays absorption bands for methylene bending and ether stretching vibrations, but it lacks bands for asymmetric and symmetric methyl vibrations. It should also be noted that the C=O stretching vibration for PD is shifted to a lower frequency than that of either PL or PG, thereby distinguishing PD from PL and PG. This shift could be explained by the close proximity of ester groups in PLLA and PGA, where opposing dipoles could increase force constants and shift the absorption bands to higher frequencies. According to these cumulative results, the specific FT-IR absorption bands corresponding to C=O, -CH_3, -CH_2-, and C-O-C can be utilized to distinguish PL, PG, and PD, despite only subtle differences in chemical structure.