• Batistella, Marcos
• Lopez-Cuesta, J.
• Pucci, Monica Francesca
• Masarra, Nour-Alhoda
• Ravel, Romain
• Quantin, Jeanchristophe
• Hage, Roland El

Abstract

Conductive fillers such as graphene are able to increase the electrical conductivity in polymer compositesystems. Beyond a certain concentration called the electrical percolation threshold, graphene particles canform interconnected 3D percolated network and thus leading to a sudden rise in the conductivity of thecomposites [1].In this context, this work aims to highlight for the first time the differences in terms of the microstructureof polymer blend composite systems based on polylactic acid (PLA 2003D, Nature Works) andpolycaprolactone (PCL Capa TM6800 , Perstorp) that are filled with 10 wt.% of graphene nanoplatelets(GNP-Grade M5, XG Sciences) and their influence on the electrical properties. The polymer compositeswereprepared using the melt blending technique via a mini twin-screw extruder. The polymer proportionswere varied (the percentage of PLA was increased from 30 wt.% to 80 wt.% in the polymer total weightpercentage). 3D printing and compression moulding techniques were used to manufacture the samples forthe conductivitytests and the microstructural analysis by scanning electron microscopy (SEM).The SEM image (Figure 1.a) is related to PLA30/PCL70/10 wt.% GNP compression moulded composite inwhich the PLA nodules (brighter phase) are dispersed in the PCL (darker phase) that contains all the GNPs.The same sea-island morphology was obatined for the 3D printed sample. And from the electricalconductivity measurement tests, this formulation showed inferior electrical performance as compared toPLA60/PCL40/10 wt.% GNP composite (Figure 1.b). The latter possesses superior conductivity due to thepresence of a co-continuous structure of PLA and PCL phases in addition to the selective localization of thegraphene in the PCL phase. This phenomenon is related to the existence of a double percolation thresholdthat exists in the case of immiscible polymer blend composites which contain filler whose preference is toone polymer phase rather than the other [2]. References [1] Marsden, A.J.; Papageorgiou, D.G.; Valles, C.; Liscio, A.; Palermo, V.; Bissett, M.A.; Young, R.J.; Kinloch, I.A.; Electrical percolation in graphene-polymer composites. 2D Materials 2018, 5, 1-34. [2] Zhang, K.; Yu, H.O.; Shi, Y.D.; Chen, Y.F.; Zeng, J.B.; Guo, J.; Wang, B.; Guo, Z.;Wang, M.; Morphological regulation improved electrical conductivity and electromagnetic interference shielding in poly(L-lactide)/poly(ε-caprolactone)/carbon nanotube nanocomposites via constructing stereocomplex crystallites. Journal of Materials Chemistry C 2017, 5, 2807-2817.

Topics

• nanocomposite
• impedance spectroscopy
• microstructure
• Carbon
• scanning electron microscopy
• nanotube
• melt
• electrical conductivity
• polymer blend
• percolated