Mechanical properties of biopolymers reinforced with carbon nanotubes
Citation:
David Blond, 'Mechanical properties of biopolymers reinforced with carbon nanotubes', [thesis], Trinity College (Dublin, Ireland). School of Physics, 2008, pp 168Download Item:
Abstract:
Three biopolymers; poly(methyl methacrylate) (PMMA); poly(L-lactic acid) (PLLA);
poly(vinyl alcohol) (PVA) and an engineered spider silk (Biosteel ®) have been independently
doped with carbon nanotubes. PM MA was functionalised with OH-functionalised multiwalled
carbon nanotubes (OH-MWNTs) by in situ polymerisation. Infrared absorbance studies
revealed covalent bonding between the polymer strands and the nanotubes. The treated
nanotubes were blended in solution with both in-house synthesised PMMA and commercial
PMMA before drop-casting to form composite films. For composites blended with in-house
synthesised PMMA, increases in the Young’s modulus (Y), breaking strength (δb), ultimate
tensile strength (δc), and toughness (T) of x1.9, x4.7, x4.6, and x 13.7 respectively were
observed upon the addition of less than 0.5 wt% nanotubes. For commercial PMMA, the
increases in the above mentioned mechanical parameters were x 1.2, x 1.5, x 1.5, and x3
respectively. In both cases, effective reinforcement was only observed for nanotube contents
of up to ~0.1 vol %. Above this volume fraction, all mechanical parameters tended to reduce,
probably as a result of nanotube aggregation. In addition, scanning electron microscopy
(SEM) studies of the composite fracture surfaces after film breakage showed that a polymer
layer coated the nanotubes. The fact that the polymer rather than the interface fails suggests
that functionalisation results in an extremely high polymer/nanotube interfacial shear strength.
Author: Blond, David
Advisor:
Blau, WernerPublisher:
Trinity College (Dublin, Ireland). School of PhysicsNote:
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Full text availableKeywords:
Physics, Ph.D., Ph.D. Trinity College DublinMetadata
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