EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Graphene is a 2D single layer of hybridized sp² carbon atoms covalent bond in a hexagonal structure (honeycomb type). Due to their unique mechanical properties, such as Young's modulus of 1.0 TPa and tensile strength of 130 GPa, graphene has become an attractive candidate as a structural reinforcement for polymer nanocomposites [1], [2]. However, the production of pure graphene is quite challenging and its industrial applications in nanocomposites are very limited at this stage. On the other hand, graphene nanoplatelets (GNPs) can combine large-scale production and low costs for the development of advanced materials with remarkable properties [3]. Nowadays, GNPs are supplied by several companies, which makes a detailed analysis of these materials an important requirement, namely when comparative studies are envisaged for nanocomposites properties containing GNPs of different sources.

Herein, we report the properties of poly(propylene) (PP)–based nanocomposites reinforced with GNPs of different origin. Some properties of GNPs have been assessed by chemical, structural, and microscopic analysis. PP nanocomposites reinforced with 1 wt.% of GNPs were compounded by melt blending technique, using a Brabender type internal mixer. A mini-injection moulding machine was used to obtain specimens for mechanical tests.

Overall, our results have shown an improvement of the mechanical properties of the GNPs reinforced PP nanocomposites as compared to the polymer matrix. A better mechanical performance was achieved for PP nanocomposites processed with GNPs with the smallest average nanoplatelet size, highest specific surface area and most functional groups in its structure. Noteworthy, some differences have been observed depending on the type of GNPs employed as fillers, which highlights the importance of pre-screening the properties of commercial GNPs before their application in polymer-based nanocomposites.