Structural-nanomechanical property correlation of shallow water shrimp (Pandalus platyceros) exoskeleton at elevated temperature

Abstract

This investigation reports the nanomechanical properties of shallow water shrimp exoskeleton at temperatures ranging from 30 °C to 80 °C measured using nanoindentation experiments. Scanning Electron Microscopy (SEM) measurements suggest that the shrimp exoskeleton has the Bouligand structure in its layers, a key characteristic of the crustaceans. The thickness of the layers and packing density are found to be different from that of lobsters and crabs reported earlier in the literature. Mechanical properties at high temperatures are determined using micro materials nanoindentation test set up combined with the hot stage. The properties measured during nanoindentation test are corrected for the creep and thermal drift during the experiments. The reduced modulus values are found to be around 28 GPa at 30 °C that reduces to approximately 24 GPa at 80 °C. The hardness values also decrease from 1.6 GPa at 30 °C to around 1.2 GPa at 80 °C. The indentation size effect is found to be absent at all temperatures. Creep mechanisms of polymers like materials and its temperature dependence are discussed to give more insight into the deformation mechanism.