Nano-mechanical behaviour of biochar-starch polymer composite: Investigation through advanced dynamic atomic force microscopy

Abstract We investigated the nano-mechanical behaviour of rice husk biochar (RHBC)/starch polymer composite using the amplitude modulation-frequency modulation (AM-FM) mode available within the atomic force microscopy. The interaction of biochar with the starch matrix in the interfacial region, the surface morphology and viscoelastic properties of the composite were studied through AM-FM mapping. The Young’s modulus of the biochar-starch polymer composites was correlated with the biochar dosage in the polymer composite. A weak interaction of the RHBC with the starch matrix was observed leading to a decrease in Young’s modulus of the composite from 1.1 GPa to 0.7 GPa. The poor interaction of the RHBC with starch matrix was attributed to the absence of hydroxyl functional group in RHBC. Comparison of the loss tangent between the neat starch polymer and 5% RHBC, showed a subtle increase in the loss tangent suggesting increased viscous nature of the composite with the addition of RHBC.