Thermal degradation of poly(3-hydroxybutyrate)/poly(ethylene oxide) blends: Thermogravimetric and kinetic analysis

Thermal stability of poly(3-hydroxybutyrate)/poly(ethylene oxide) (PHB/PEO) blends has been investigated by non-isothermal thermogravimetry in an inert atmosphere. PHB/PEO blends were prepared by hot-melt extrusion. Neat polymers decompose in one stage and PHB/PEO blends in two degradation stages, respectively. It was found that the degradation of investigated blends starts at lower temperatures and occurs more slowly by addition of PEO, that could be an indication of PEO's destabilising effect on PHB. Kinetic analysis of the non-isothermal degradation of PHB/PEO blends was performed using isoconversional Friedman (FR) method in combination with the multivariate non-linear regression method. The kinetic analysis indicated three-stage degradation mechanism for all investigated samples, except for PEO sample which showed two-stage degradation mechanism. PEO showed higher value of activation energy confirming its superior thermal stability to PHB. (C) 2016 Elsevier Ltd. All rights reserved.