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Tuning the Mechanical Properties of Composites from Elastomeric to Rigid Thermoplastic by Controlled Addition of Carbon Nanotubes
Author(s) -
Khan Umar,
May Peter,
O’Neill Arlene,
Vilatela Juan J.,
Windle Alan H.,
Coleman Jonathan N
Publication year - 2011
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201001959
Subject(s) - materials science , carbon nanotube , elastomer , composite material , thermoplastic elastomer , thermoplastic , carbon fibers , polymer , composite number , copolymer
A commercial thermoplastic polyurethane is identified for which the addition of nanotubes dramatically improves its mechanical properties. Increasing the nanotube content from 0% to 40% results in an increase in modulus, Y , (0.4–2.2 GPa) and stress at 3% strain, σ ϵ = 3% , (10–50 MPa), no significant change in ultimate tensile strength, σ B , (≈50 MPa) and decreases in strain at break, ϵ B , (555–3%) and toughness, T , (177–1 MJ m −3 ). This variation in properties spans the range from compliant and ductile, like an elastomer, at low mass fractions to stiff and brittle, like a rigid thermoplastic, at high nanotube content. For mid‐range nanotube contents (≈15%) the material behaves like a rigid thermoplastic with large ductility: Y = 1.5 GPa, σ ϵ = 3% = 36 MPa, σ B = 55 MPa, ϵ B = 100% and T = 50 MJ m −3 . Analysis suggests that soft polyurethane segments are immobilized by adsorption onto the nanotubes, resulting in large changes in mechanical properties.