Preparation and characterization of a novel starch–chestnut husk biocomposite

Biocomposites based on potato starch and reinforced with chestnut husks, a lignocellulosic agroforestry waste, were developed by incorporating 2.5 wt%, 5 wt% and 7.5 wt% of chestnut husks via an extrusion molding procedure. The effect of the filler on the morphology and thermos-mechanical properties were studied by scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and dynamic mechanical analysis (DMA). Chestnut husks were homogeneously dispersed within the plasticized starch matrix as shown by SEM images. FTIR results shows that the peaks of pure starch samples in the 500–1500 cm⁻¹ region vanished as chestnut husks was incorporated, suggesting an interaction between starch and chestnut. The glass transition temperature was found to decrease at higher filler content, which indicates an improvement in segmental mobility of starch molecules. DMA tests revealed the presence of two relaxation processes. The α relaxation was associated with the cooperative segmental motion of starch chains while the β relaxation was assigned to the segmental mobility of glycerol-rich phases.