Avaliação da utilização de um agente de acoplamento de fonte renovável em nanocompósitos de polipropileno e óxido de grafeno

Abstract

Graphene oxide-based nanocomposites tend to have better mechanical and thermal properties than pure polymers. The main disadvantage is the poor adhesion between the polymer matrix and the graphene oxide (OG). The present work analyzes the action of itaconic acid (AI) with addition contents of 2 %, 4 % and 8 % by mass as a coupling agent in polypropylene (PP) nanocomposites reinforced with 0.5 % by mass of graphene oxide. Samples of PP, PP/OG, PP/OG/2AI, PP/OG/4AI and PP/OG/8AI were prepared in a thermokinetic mixer, followed by compression molding. Morphology was evaluated by scanning electron microscopy, thermal stability by thermogravimetric analysis and mechanical properties by flexural strength and impact strength tests. Good dispersion and weak adhesion of the filler to the polymer matrix was observed. The flexural strength properties of the nanocomposites were better compared to the polypropylene sample, with an increase of approximately 23% in the flexural modulus value for the PP/OG nanocomposite. In the impact resistance test, the nanocomposites showed more fragility, probably due to the presence of voids, observed in the micrographs. There was also no increase in the mechanical properties evaluated when comparing the PP/OG nanocomposite and the PP/OG/2AI, PP/OG/4AI and PP/OG/8AI nanocomposites due to a possible volatilization of itaconic acid during processing. Furthermore, samples containing graphene oxide showed greater thermal stability, probably due to the homogenization of the nanofiller. [resumo fornecido pelo autor]