Structure and properties of pregelatinized cassava starch/kaolin composites

Pregelatinized cassava starch/kaolin composites were prepared using compression molding. The morphology of the fractured surfaces, retrogradation behavior, thermal decomposition temperatures and mechanical properties of the composites were investigated using scanning election microscopy (SEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and tensile testing, respectively. The tensile strengths and thermal degradation temperatures of the composites were higher than for thermoplastic starch (TPS). The retrogradation behavior of the composites was hindered by kaolin. The water absorption was measured after aging for 12 and 45 days at a relative humidity (RH) of 15% and 55%. It indicated that all the composites displayed lower water absorption values than TPS.

► Pregelatinized starch/kaolin composites were prepared using compression molding.
► The tensile strengths of the composites were higher than for thermoplastic starch.
► Degradation temperatures of the composites were higher than for thermoplastic starch.
► The retrogradation behavior of the composites was hindered by kaolin.