Thermal degradation of poly(3-hydroxybutyrate) plasticized with acetyl tributyl citrate

The effects of acetyl tributyl citrate (ATBC) as a biodegradable plasticizer on the thermal stability of poly(3-hydroxybutyrate) (PHB) were studied by differential scanning calorimetry (DSC) and by thermogravimetric (TG) methods under dynamic conditions. The amounts of ATBC varied from 10 wt.% to 30 wt.% relative to PHB. The thermal degradation of pure and plasticized PHB samples was investigated by DSC as a function of annealing temperature, annealing time and cooling rate after thermal treatment. Important thermal parameters, including the melting temperature, the melting enthalpy, degree of crystallinity, initial degradation temperatures (expressed as the onset temperature, the temperature for 1% and 5% of conversion and the temperature at the maximum degradation rate) were determined.