Synthesis and characterization of star-shaped carboxyl group functionalized poly(lactic acid) through polycondensation reaction
Abstract
Present paper deals with the preparation and characterization of carboxyl-functionalized poly(lactic acid) (PLA) of non-linear, star-shaped architecture prepared by direct melt polycondensation of lactic acid and pentetic acid - applied as a star polymer core. Influence of the optical purity of the lactic acid (L or DL) on the structure and properties of the product is investigated in close details.
The influence of pentetic acid core on molar mass, as analysed by the means of gel permeation chromatography using triple detection (refractive index, light scattering and viscometric detectors) is performed as a detailed survey. Furthermore FTIR and NMR spectra, end group analysis, and water contact angle measurements were analysed to receive detailed product characteristics.
Differential scanning calorimetry was carried out to examine thermal properties. Obtained results confirm the possibility of the starshaped structure preparation using a simple polycondensation reaction.
The properties of the prepared polymers were found to be dependent on optical purity of the lactic acid precursor.