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Title: Polymer nanocomposites : preparation and characterisation of polyamide 6/graphene composites produced via in situ polymerisation
Author: O’Neill, Aidan
ISNI:       0000 0004 5922 0577
Awarding Body: Ulster University
Current Institution: Ulster University
Date of Award: 2016
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Nanocomposites have many applications in engineering as high strength , light weight structural materials. In the following work, composites were prepared via in situ ring opening polymerisation of £-caprolactam in the presence of single layer graphene oxide, chemically reduced graphene oxide and colloidally dispersed graphene oxide. Finally, chemically engineered nanoparticles were produced via the functionalisation of GO with the amide (CONH2) functional group, and subsequent polymerisation was carried out in the presence of this amide-GO. The structure and physicochemical properties of the different graphenes, before and after polymerisation (via isolation from composite), were investigated alongside the properties of the composites. The single layer nature of the GO used was confirmed, and the reduction of all graphene oxides during polymerisation (via either thermal or chemical means) was observed. Similarly, functionalisation (via physical or chemical attachment) of all graphene flakes with PA6 chains has been shown to occur during polymerisation. The retention of some oxygen functionalities after reduction was identified; specifically, doubly bound oxygen species. It is also suggested that the graphene acts as a base for polymerisation with polymer chains propagating from the surface. The promotion of a phase crystallite formation was detected and is related to filler wt%, as the graphene acts as a crystal nucleation site. Young's modulus increased proportionally with increases in both colloidally dispersed GO and amide functionalised GO content. A linear improvement in stiffness and yield strength was observed as graphene content increased; however, overall yield strength for functionalised composites was marginally lower than control PA6. This work shows for the first time the process of GO reduction during composite manufacture, with the first report of polyamide 6/reduced graphene oxide composites and the use of new amide-functionalised graphene oxide. The production of graphene nanocomposites will advance in parallel with progressions in the complex area of graphene manufacture.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available