Thermoplastic Polyurethane Nanocomposites Produced via Impregnation of Long Carbon Nanotube Forests

Abstract

TPU was infiltrated into vertically aligned, 3.5 mm‐long MWNT forests to produce continuously reinforced anisotropic nanocomposites, and thermomechanical and electrical testing has revealed multifunctionality which shows promise for numerous applications. A 1000% increase in the storage modulus at 70 °C was observed as compared to the neat TPU, and these continuously aligned composites showed electrical conductivity two orders‐of‐magnitude greater (≈1.5 S · cm−1) than randomly aligned composites prepared using CNTs from these forests. The heightened improvement for the continuously reinforced composite appears to be owed to the extremely high aspect ratio of these CNTs and the interconnected network which remains after infiltration. magnified image

Fabrication of High Content Carbon Nanotube–Polyurethane Sheets with Tailorable Properties

“…Solubility modulation is a simple method that has been used to control the morphology of various materials. , The use of a nonsolvent (e.g., methanol) can induce phase separation of the UAF 472 TPU dissolved in a good solvent (e.g., acetone, THF, or DMF) starting at a specific solvent/nonsolvent volume ratio. In the absence of CNTs, a cloudy suspension is obtained (Figure a) when methanol is added to a solution of TPU in acetone to a 50:50 vol % solvent ratio due to phase separation.…”

Thermoplastic Nanocomposites and Their Processing Techniques

“…Hence, CNTs have been extensively studied since the discovery by Iijima in 1991 (Ando, 2010). Having said this, pristine CNTs did not yet met early expectations; however their incorporation into polymer materials to prepare nanocomposites, have extend their applications, despite inconsistencies in properties due to (i) CNTs synthesis method and the resultant aspect ratio, (ii) their post-processing (such as purification), and (iii) the characteristics of polymer matrix and the nanocomposite fabrication procedure (such as solution blending, melt blending, or in situ polymerization) (Silva et al, 2011). It is therefore necessary to entertain a compromise between the properties and processing, since only low loadings of nano-filler are needed to reinforce the matrix, which might exhibit improved stiffness without scarifying toughness (Chang et al, 2006).…”

A Comparative Study of Compressible and Conductive Vertically Aligned Carbon Nanotube Forest in Different Polymer Matrixes for High-Performance Piezoresistive Force Sensors

“…PU has also found increasingly outstanding applications as elastomers 29 as well as rigid and flexible forms. 30,31 Silva et al 32 observed heightened improvement of thermomechanical and electrical properties of anisotropic nanocomposites of PU vertically aligned multiwalled CNT forest. Epoxy resins have remarkable mechanical properties, affordable cost, facile processing, and fine adhesion to numerous substrates, so they are widely recognized as thermosetting matrixes for advanced composites holding numerous applications.…”

“…Han et al and Pyo et al developed printed PDMS/CNTs piezoresistive pressure sensors that could detect three-dimensional forces. PU has also found increasingly outstanding applications as elastomers as well as rigid and flexible forms. , Silva et al observed heightened improvement of thermomechanical and electrical properties of anisotropic nanocomposites of PU vertically aligned multiwalled CNT forest. Epoxy resins have remarkable mechanical properties, affordable cost, facile processing, and fine adhesion to numerous substrates, so they are widely recognized as thermosetting matrixes for advanced composites holding numerous applications. − Toshio Ogasawara et al examined the elastic modulus and ultimate tensile strength of aligned CNTs/epoxy composites as 50.6 GPa and 183 MPa.…”