Study on the thermal degradation behavior and flame-retardant property of polylactide/PEDPP blends

A phosphorus-containing polyester, poly (ethylene diglycol phenylphosphinate) (PEDPP) was synthesized from phenylphosphonic dichloride and ethylene diglycol. The structure of PEDPP has been determined by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance and matrix assisted laser desorption ionization-time of flight-mass spectrometer. A series of polylactide (PLA) blends with various content of PEDPP as flame retardant was prepared by direct melt compounding; the PLA/PEDPP blend is partially miscible. PEDPP is an effective flame retardant for PLA. The limiting oxygen index values increased from 19.7% for pure PLA to 29.0% for the blend containing 10wt% PEDPP. Thermogravimetric analysis-FTIR analysis indicated that the PEDPP affected the pyrolytic decomposition process of PLA, which is established by the change of the pyrolytic decomposition rate and the gross mass of gaseous fuel formation. The pyrolytic decomposition activation energies of PLA and PLA/10%PEDPP were estimated via FlynnWallOzawa method. Copyright (c) 2013 John Wiley & Sons, Ltd.