Functionalised polymer nanocomposites and blends

Spoljaric, S 2011, Functionalised polymer nanocomposites and blends, Doctor of Philosophy (PhD), Applied Sciences, RMIT University.


Document type: Thesis
Collection: Theses

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Title Functionalised polymer nanocomposites and blends
Author(s) Spoljaric, S
Year 2011
Abstract Functionalised polymer composites and blends were prepared with the aim of enhancing the mechanical and thermal properties of the polymer matrix, while maintaining the characteristic property (functionality) of the introduced functional group. This involved the use of nanoparticles with novel architecture (core cross-linked star polymers, POSS-functionalised dendrimers, telechelic POSS) to provide attributes for improving mechanical and thermal stability, in addition to physical aging stability and phase selectivity. Furthermore, nanoparticles were functionalised to provide attributes such as colour (dye-functionalised POSS) and magnetism (magnetite-functionalised carbon nanotubes). These nanoparticles were investigated in amorphous polymer matrices, with structure-property relationships explored.

Core cross-linked star (CCS) increased the glass transition temperature (Tg) and decreased shrinkage of linear polystyrene and poly(methyl methacrylate). This was attributed to reduced volume within the blends and CCS polymer ‘arms’ imparting restrictions on segmental motions of polymer chains. These restrictions also enhanced thermomechanical properties and retarded structural relaxation. Volume relaxation was successfully observed in real time, creating a novel application for modulated temperature – thermomechanometry. POSS-functionalised dendrimers and telechelic POSS enhanced the thermal and mechanical properties of their respective elastomer matrices. Phase preference was successfully achieved via compatibilising ‘R’ groups on the POSS. Colour intensity was able to be controlled by altering the dye-functionalised POSS concentration. Material properties were influenced by filler concentration, phase preference and POSS architecture. Films became more magnetic with increasing carbon nanotube/magnetite concentration and films displayed superior mechanical and thermal properties. Melt-mixing was more effective at de-agglomerating and distributing functionalised CNTs than solvent dispersion. As a result, melt-mixed composites exhibited more dramatic changes in material properties and displayed superior magnetic, mechanical and thermal properties than their solvent dispersed counterparts.
Degree Doctor of Philosophy (PhD)
Institution RMIT University
School, Department or Centre Applied Sciences
Keyword(s) Functionalisation
Nanocomposites
Blends
Elastomers
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Created: Fri, 14 Sep 2012, 11:09:21 EST by Brett Fenton
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