Rheological behavior of polypropylene/carbon quantum dot nanocomposites: the effects of particles size, particles/matrix interface adhesion, and particles loading

The effects of nanoparticles size, nanoparticles/matrix interface adhesion, and nanoparticles loading on the rheological properties of polypropylene (PP)/carbon quantum dot (CQD) nanocomposites were investigated. The storage modulus of the samples was found to be raised with an increase in the volume fraction of CQDs up to 1 wt%. The addition of the compatibilizer had no significant effect on the storage and loss modulus of the samples; however, it resulted in the reduction in the viscosity at the lower frequencies. With increasing the CQDs size, the rise in the loss modulus was found to be greater than that of the storage modulus. The damping factor of the samples was lower for the smaller size nanoparticles at the lower frequencies. Also, the size of the nanoparticles had no significant effect on the complex viscosity of the samples. The storage modulus obtained from the Cohan model deviated the most from the experimental results for the samples containing various loadings of CQDs.