Thermomechanical improvement of glycerol plasticized maize starch with high loading of cellulose, flax and talc fillers

For the purpose of extending the applicability fields of thermoplastic starch ( TPS ), a study on their properties with high filler loadings was performed. Two different organic natural reinforcements (cellulose and flax) and a typical mineral filler (talc) were incorporated in TPS using melt blending. The resulting composites were observed on fragile fracture surfaces by scanning electron microscopy to study the filler/matrix adhesion. Magnifications revealed good TPS −fibre interfacial interaction with limited debonding. The thermomechanical properties by dynamic mechanical thermal analysis ( DMTA ) and the correlation with the filler amount (from 10 to 50 wt%) were thoroughly investigated at 50% relative humidity and 23 °C. The tests evidenced a huge increase in composite storage moduli ( E ′) of more than 200% with respect to the neat matrix. Moreover, the resulting DMTA experimental data were interpolated with the Cox − Krenchel micromechanical model. To this aim, the necessary measures of the filler dimensions were calculated after the extrusion process on water‐dissolved residues using an optical microscope. This model was able to correctly follow the experimental results also at high filler loadings.