Thermal degradation of plasticized poly(3-hydroxybutyrate) investigated by DSC

The thermal degradation of poly(3-hydroxybutyrate) (PHB) in the presence of two plasticizers (glycerol, glycerol triacetate) was investigated by differential scanning calorimetry (DSC). The thermal degradation was studied as a function of the annealing time, temperature and cooling rate after the thermal treatment. PHB thermal degradation proceeds by the random scission of the polymer chain. The presence of glycerol leads to a significant prodegradative effect on PHB presumably due to the alcoholysis reaction, while glycerol triacetate (triacetine) behaved as an almost inert additive from this point of view. Size exclusion chromatography (SEC) confirmed the results obtained by the DSC method. The data lead to the conclusion that DSC is a suitable method for estimation of PHB thermal degradation. (C) 2002 Elsevier Science Ltd. All rights reserved.