THERMOANALYTICAL STUDY OF THE EFFECT OF EAA AND STARCH ON THE THERMOOXIDATIVE DEGRADATION OF LDPE

The effect of ethylene-acrylic acid copolymer (EAA) and plasticized st arch (PLST) upon the thermo-oxidative degradation of low density polye thylene (LDPE) was examined. The course of oxidation was followed usin g thermogravimetric analysis (TGA) to monitor the weight changes durin g heating and Differential Scanning Calorimetry (DSC) to study the hea t changes taking place during oxidation. Three types of blends were ex amined: LDPE-plasticized starch (PLST), LDPE-EAA and LDPE-starch-EAA b lends. All blends contained cobalt stearate as prooxidant (PRO). Measu rements verify previous findings that EAA accelerates LDPE thermo-oxid ation whereas PLST inhibits it. Using the TGA method, the best results were obtained by isothermal heating of the samples at 190 degrees C w hereas with DSC, dynamic measurements using low heating rates were bet ter. (C) 1997 Elsevier Science Limited.