Evaluation of thermomechanical properties of polyvinyl butyral nanocomposites reinforced with graphene nanoplatelets synthesized by in situ polymerization

In this work, polyvinyl butyral (PVB) nanocomposites reinforced with 0.5 to 2.5 wt % of graphene oxide (GO) and graphene nanoplatelets (GNP) were synthesized via in situ polymerization. Dynamic mechanical analysis showed that PVB/GO 2.5 wt % nanocomposites present the largest storage modulus, with increases of 10 °C in the PVB glass transition temperature. The degree of entanglement and the reinforcement efficiency factor (C coefficient) were evaluated using the dynamic mechanical analysis results and correlated with scanning electron microscopy analyses. The degree of entanglement and C coefficient values were higher for PVB/GO 2.5 wt %, enabling the enhancement of PVB mechanical properties. The adhesion factor A was used to evaluate the interfacial interaction, evidencing an improvement in the nanoparticle/matrix adhesion for PVB/GO 2.5 wt % caused by interactions between GO oxygenated groups. For the samples reinforced with GNP, the results of storage modulus, degree of entanglement, coefficient C, and adhesion factor A were not significantly modified, due to weak interfacial interactions with PVB, preventing the exfoliation of GNP in PVB during the in situ polymerization process. Therefore, in situ polymerization will improve the dispersion and final properties of the nanocomposite with PVB only if the nanoparticle has a relevant interfacial interaction during the synthesis process. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46157.