Strong dependence of mechanical properties on fiber diameter for polymer-nanotube composite fibers: differentiating defect from orientation effects.
ACS Nano
; 4(11): 6989-97, 2010 Nov 23.
Article
em En
| MEDLINE
| ID: mdl-20945879
ABSTRACT
We have prepared polyvinylalcohol-SWNT fibers with diameters from â¼1 to 15 µm by coagulation spinning. When normalized to nanotube volume fraction, V(f), both fiber modulus, Y, and strength, σ(B), scale strongly with fiber diameter, D Y/V(f) â D(-1.55) and σ(B)/V(f) â D(-1.75). We show that much of this dependence is attributable to correlation between V(f) and D due to details of the spinning process V(f) â D(0.93). However, by carrying out Weibull failure analysis and measuring the orientation distribution of the nanotubes, we show that the rest of the diameter dependence is due to a combination of defect and orientation effects. For a given nanotube volume fraction, the fiber strength scales as σ(B) â D(-0.29)D(-0.64), with the first and second terms representing the defect and orientation contributions, respectively. The orientation term is present and dominates for fibers of diameter between 4 and 50 µm. By preparing fibers with low diameter (1-2 µm), we have obtained mean mechanical properties as high as Y = 244 GPa and σ(B) = 2.9 GPa.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
ACS Nano
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Irlanda