Thermal stability and degradation behavior of hydroxyethyl methacrylate-poly(lactide) polymers

ABSTRACT

Hydroxyethyl methacrylate (HEMA)-Poly(L-lactide) (PLA) polymers, with different molar ratios of HEMA/lactide (1/4 and 1/8), were synthesized by ring-opening polymerization. The thermal degradation behavior and kinetic parameters of these obtained HEMA-PLA polymers were analyzed by thermogravimetric analysis (TGA) and Pyrolysis-Gas chromatography/Mass spectrometry (Py-GC/MS). It was found that the activation energies of thermal degradation of the polymers increased as the residue weight was decreased, indicating that the mechanism of thermal decomposition changes during the process progress. The results showed that the random chain scission proceeded at lower temperature, and subsequently the specific chain scission did so. Moreover, the results revealed that thermal stability of PLA was increased by the copolymerzation of HEMA. In addition, Py-GC/MS analysis showed that the main decomposed products obtained from the HEMA-PLA polymers were HEMA, lactide, dimer, trimer and tetramer.

KEYWORDS:

• Poly(L-lactide)
• hydroxyethyl methacrylate
• thermal degradation
• kinetic parameters