Mechanical properties of non-functionalized multiwall nanotube reinforced polycarbonate at 77 K

Mechanical properties of non-functionalized, multiwall carbon nanotube (CNT) reinforced polycarbonate composites are studied at room temperature and 77 K. Five sample groups are tested, ranging from 0 to 10.0 wt% CNT. The dispersion, interfacial bonding, bundling and CNT content, as well as the testing temperature, play a major role as regards mechanical properties. Mechanical testing shows increase in strength with increasing CNT content as well as an increase in Young's modulus and a decrease in ductility. The distribution of yield strength data for each sample group is analyzed using Weibull distributions. It is evident that interfacial debonding increases at low temperature. Higher CNT concentration samples are affected the most, which is reflected in a decrease in their impact on the mechanical properties at 77 K compared to RT. Scanning electron microscopy of fracture surfaces supports the interpretation of the measurement results.