Characterization of the prepolymer and gel of biocompatible poly(xylitol sebacate) in comparison with poly(glycerol sebacate) using a combination of mass spectrometry and nuclear magnetic resonance

Atmospheric pressure chemical ionization (negative ion) and electrospray ionization (positive and negative ion) mass spectrometry and nuclear magnetic resonance (1H NMR and 13C NMR) were used to characterize the prepolymer (i.e. uncrosslinked) poly(xylitol sebacate) (PXS), prepared by condensation of xylitol [X] and sebacic acid [S], and this was compared with poly(glycerol sebacate) (PGS), prepared by condensation of glycerol [G] and [S]. The PXS prepolymer, prepared at 118 °C/24 h, gave predominantly 1‐acyl‐[XS] and 1,5‐diacyl‐[SXS] species and smaller amounts of 2‐acyl substitutions. At 130 °C/24 h an increase of the amount of the 1‐acyl and 1,5‐diacyl substitutions in the [(SX)n], [S(XS)n] and [(XS)nX] series was identified, as was found for the analogous PGS prepolymer ([(SG)n], [S(GS)n] and [(GS)nG] series). Novel tetrahydrofuranyl species were found in the PXS prepolymer. Further polymerization of the PXS prepolymer gave a gel which when analysed using 13C NMR was shown to mainly contain 1‐acyl and 1,5‐diacyl substitutions.