Comparing the Rheological and Reinforcing Effects of Graphene Oxide on Glassy and Semicrystalline Polymers

In this work, a comparative study was performed on nanocomposites, based on three different polymeric matrices, namely polylactic-acid (PLA), polystyrene (PS), and linear low-density polyethyelene (mLLDPE), produced by metallocene catalyst. The reinforcing agent was graphene oxide (GO) at one percentage content (1 wt%) and the nanocomposites were prepared by the melt-mixing procedure, whereas the matrix type employed was found to be decisive in the thermomechanical properties improvement. The thermomechanical performance of these material systems was studied by scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, tensile testing, and creep and stress relaxation. The mechanical and rheological performance was comparatively studied, and an attempt was made to relate the macroscopic response with the nanocomposites micromorphology. Furthermore, the tensile response was analyzed by a viscoplastic model, introduced earlier, and the model parameters involved provide additional evidence about the nanocomposites micromorphology. The findings of the comparative study are encouraging, regarding the potential of PLA and mLLDPE as matrices for graphene-based nanocomposites at higher GO loadings. POLYM. ENG. SCI., 2019. (c) 2019 Society of Plastics Engineers