https://www.sciencedirect.com/science/article/abs/pii/S092633731500346X
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Date
2016
Authors
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Journal ISSN
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Publisher
Wiley
Abstract
We have synthesized unique flexible pressure-sensitivenanocomposites by means of a solution mixing method,by adding multiwalled carbon nanotubes (MWCNTs) into athermoplastic urethane (TPU) matrix along with poly(methyl methacrylate) (PMMA) microbeads of varioussizes. The influence of the various PMMA bead sizes onthe pressure sensing properties of the nanocompositeswas studied over a range of pressures. The PMMAmicrobeads were used to achieve an early percolationthreshold at low loadings of MWCNTs. We used scanningelectron microscopy to study the nanocomposites’ mor-phology, and conducted differential scanning calorimetryanalyses to investigate their thermal properties. The nano-composites’ electrical and thermal conductivities werealso measured under various applied pressures. Thenanocomposites displayed repeatable electricalresponses under various applied pressures, demonstrat-ing their suitability for use as pressure sensing materials.The proposed material is an ideal candidate for use in thepreparation of pressure-sensitive devices
Description
TPU-CNT nanocomposites were prepared by means of asolution mixing technique. PMMA microbeads of different sizes(i.e., 5, 10, and 20 lm) were dispersed in the nanocompositematrix in order to understand the effect of bead size upon thepressure dependence of the electrical and thermal conductivitiesin the resulting nanocomposites. When pressure was applied tothe nanocomposites, CNTs present in the TPU matrix cameclose to each other and formed three-dimensional conductingnetwork structures at the percolation threshold. PMMA microbe-ads present in the nanocomposites helpe d to achieve th is contactbetween CNTs at low CNT loadings. The nanocomposites incor-porating 10 mm beads showed the highest thermal conductivity;this phenomenon was explained by SEM analysis. DSC resultsconfirmed possible interactions between the different compo-nents in the TPU matrix. Based on these results we can con-clude that the nanocomposite with 10 mm bead size is the bestchoice for application as a pressure sensing material
Keywords
Carbon nanotube; Nanocomposites; pressure sensor