Graphene/elastomer nanocomposites

Abstract

Abstract The University of Manchester Doctor of Philosophy Mufeng Liu 2019 Graphene/elastomer nanocomposites The mechanisms of mechanical reinforcement of elastomers by graphene have been studied in detail. The study comprises two aspects primarily: uniaxial and biaxial reinforcement by the graphene nanoplatelets (GNPs). The effects of the filler morphologies, filler orientation and filler/matrix interfaces on the mechanical reinforcement were investigated. Raman spectroscopy and analytical modelling have been demonstrated to be useful in studying graphene/elastomer nanocomposites. The graphene/elastomer nanocomposites employed were prepared using melt mixing using three sizes of GNPs and a range of different elastomers, including thermoplastic elastomers, natural rubber and nitrile butadiene rubber. It was revealed that the GNPs were generally oriented in-plane due to the pressure involved in the moulding processes. Another morphology of the GNPs within the elastomeric matrices was loops/folds that existed prior to the processing of the nanocomposites. The evaluation of the mechanical reinforcement by the GNPs using tensile testing suggested that the addition of the GNPs improved the stiffness and strength of the materials significantly. Raman in situ band shift measurements indicated that the stress transfer efficiency from the elastomers to the GNPs was low. The study using analytical modelling indicated that the reinforcement of graphene in graphene/elastomer nanocomposites is dependent upon the orientation, aspect ratio and volume fraction of the filler and independent of the filler modulus. When exposed to solvents, graphene/elastomer nanocomposites show an interesting anisotropic swelling phenomenon, induced by the in-plane orientation of the GNPs. The dimensional swelling can be predicted accurately by the theory proposed. The theoretical analysis and the Raman band shift during biaxial deformation of the nanocomposites indicated that graphene was able to provide constraining in-plane biaxial force through the interface when the GNPs are oriented in-plane.

Date of Award	1 Aug 2020
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Robert Young (Supervisor) & Ian Kinloch (Supervisor)