Thermoreversibly Cross-Linked EPM Rubber Nanocomposites with Carbon Nanotubes

Abstract

Conductive rubber nanocomposites were prepared by dispersing conductive nanotubes (CNT) in thermoreversibly cross-linked ethylene propylene rubbers grafted with furan groups (EPM-g-furan) rubbers. Their features were studied with a strong focus on conductive and mechanical properties relevant for strain-sensor applications. The Diels-Alder chemistry used for thermoreversible cross-linking allows for the preparation of fully recyclable, homogeneous, and conductive nanocomposites. CNT modified with compatible furan groups provided nanocomposites with a relatively large tensile strength and small elongation at break. High and low sensitivity deformation experiments of nanocomposites with 5 wt % CNT (at the percolation threshold) displayed an initially linear sensitivity to deformation. Notably, only fresh samples displayed a linear response of their electrical resistivity to deformations as the resistance variation collapsed already after one cycle of elongation. Notwithstanding this mediocre performance as a strain sensor, the advantages of using thermoreversible chemistry in a conductive rubber nanocomposite were highlighted by demonstrating crack-healing by welding due to the joule effect on the surface and the bulk of the material. This will open up new technological opportunities for the design of novel strain-sensors based on recyclable rubbers.

Toward Multi-Functional Road Surface Design with the Nanocomposite Coating of Carbon Nanotube Modified Polyurethane: Lab-Scale Experiments

“…The developed CNT/PU coatings can generate a large amount of heat due to the Joule heating effect [ 16 , 17 , 18 ]. According to Joule heating, the power increased according to where V is the applied voltage, I is the applied current, and R is the resistance of the CNT/PU coating.…”

Self-Healing Polymer Nanocomposite Materials by Joule Effect

“…When the temperature begins to drop, it allows the cycloaddition reaction to take place again, completing the DA/r-DA cycle that confers the reversibility characteristic to polymers bearing diene and/or dienophile functional groups [ 14 ]. DA adducts can be formed between DA-functionalized polymer mixtures, as well as cross-linking agents, or the adducts can also be formed through covalent interfacial bonds between a DA-functionalized polymer matrix and carbonaceous nanofillers [ 77 , 78 , 79 ]. The latter provides reversibility to a cross-linked polymer nanocomposite network at the nanoscopic interface [ 80 ].…”

Thermoreversible Polymeric Nanocomposites

“…Properties such as self-healing and shape memory, besides the "classical effects" on thermal and mechanical ones, are easily added to the composite behavior. The sensitivity to multiple external stimuli such as electricity, irradiation, and heat [11,18,53,54], represents a focal point for the design of smart materials. An added value in this case is the possibility (via irradiation) of remote-induced self-healing as well as of ultrafast kinetics [55].…”