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Title: An investigation into the use of cellulose nanofibre mats in the production of an aesthetic orthodontic bracket
Author: Boyd, Stephen A.
ISNI:       0000 0004 2725 1643
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2011
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Nanofibres can be produced from the electrospinning of a number of solutions. The aims of this investigation were to develop a novel methodology for production of a 3D mesh of cellulose acetate nanofibres. This mesh was then used to reinforce a chemically cured Bis-GMA resin matrix to produce a prototype aesthetic orthodontic bracket. A method of electrospinning cellulose acetate in a 2:1 acetone: N, N- dimethylacetamide solvent solution was identified. This method predictably produced a flat membrane of defect free cellulose acetate nanofibres in the 460nm range. The addition of 0.5% lithium chloride to the polymer solution, and further refinement of the electrospinning process resulted in production of a 3D self supporting nanofibre network. Scanning electron microscopy revealed the mean fibre diameter had further reduced to 168nm. This self supporting nanofibre network was then treated with a silane coupling agent and infiltrated, under vacuum, with an epoxy resin to produce a sample that was 25mm x 10mm x 2mm. Further experimental samples were produced using a commercially available Bis-GMA resin system (Concise?'). The prepared samples were subjected to a three point bend test to determine the flexural strength relative to unfilled controls. The experimental filled samples demonstrated reduced flexural strength when compared to the control samples. This was thought to be caused by incomplete wetting of the nanofibre filler, and air inclusion during sample preparation. In conclusion a novel method of producing a 3D self supporting network of defect free cellulose acetate nanofibres was developed. Further work is required to determine if these fibres can be used to reinforce a resin based composite.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available