Silver sulfide/poly(3-hydroxybutyrate) nanocomposites: Thermal stability and kinetic analysis of thermal degradation

The non-isothermal degradation of poly(3-hydroxybutyrate) (PHB) and silver sulfide/poly(3-hydroxybutyrate) (Ag2S/PHB) nanocomposites was investigated using thermogravimetric (TG) analysis. In the composite materials, Ag2S caused the degradation of PHB at a lower temperature as opposed to that of neat PHB. Moreover, an increase Ag2S loading in the PHB decreased the onset temperature (Tonset) of thermal degradation, whereas it was raised upon augmenting the heating rate. From Kissinger plots, the observed trend of the degradation activation energy, Ed, was attributed to polymer-particle surface interactions and the agglomeration of Ag2S. The thermal degradation rate constant, k, was linearly related to the Ag2S loading in PHB. Thus, the Ag2S nanoparticles effectively catalyzed the thermal degradation of PHB in the Ag2S/PHB nanocomposites. Differential scanning calorimetry (DSC) data also supported the catalytic property of Ag2S.