Preparation of carbon nanotube-vitrimer composites based on double dynamic covalent bonds: Electrical conductivity, reprocessability, degradability and photo-welding

Thermoresponsive, Recyclable, Conductive, and Healable Polymer Nanocomposites with Three Distinct Dynamic Bonds

“…Typical reinforced material (with 0.9 wt % CNT) and unreinforced material (without CNT) were shown to successfully undergo remolding multiple times at 100 °C for 1 h, similar to remolding conditions used by Guo et al to reprocess a CNT−vitrimer composite. 64 Recyclability of these DPNs is due to simultaneous dynamic hydrogen bonds, DA reversibility, and partially by TM exchange reaction activated at elevated temperature. No significant loss in tensile property of materials was observed after reprocessing three times (Figure 6b−e).…”

Stress Relaxation Behavior and Electrically Activated Dynamic Exchange in Carbon Nanotube-Modified Epoxy Vitrimers

“…In addition, the calculated activation energy of the dynamic network with disulfide bonds without nanomodifications was determined to be 149.8 kJ/mol. There is a higher value than the literature values reported at 55–75 kJ/mol. , The activation energy of the dynamic system with the dispersion of the CNTs in the matrix is 119.2 kJ/mol, which is also higher than the reference value of 78.11 kJ/mol of similar systems . Because this calculation leads to the estimation of the apparent activation energy and does not provide absolute activation values, it can be assumed that the obtained differences could be related to differences in the execution of the experimental campaign (e.g., differences in the stress relaxation experiment, as well as differences in the starting materials used for the preparation of the dynamic systems).…”

“…10,36 The activation energy of the dynamic system with the dispersion of the CNTs in the matrix is 119.2 kJ/mol, which is also higher than the reference value of 78.11 kJ/mol of similar systems. 17 Because this calculation leads to the estimation of the apparent activation energy and does not provide absolute activation values, it can be assumed that the obtained differences could be related to differences in the execution of the experimental campaign (e.g., differences in the stress relaxation experiment, as well as differences in the starting materials used for the preparation of the dynamic systems). Although the main contribution to the relaxation is through the exchange between the dynamic bonds, differences in the segmental mobility of the cross-linked network also play a role above T g .…”

“…16 Several studies dealing with the reconfiguration of epoxy vitrimers could benefit from the ideas generated for the remote activation of shape-memory polymers (SMPs). Guo et al 17 developed electrically conductive epoxy vitrimer composites with CNTs based on ester and disulfide bonds. They managed to reshape vitrimers by heating or radiating with NIR light intensity (with an intensity of 1.0 W/cm 2 ) and fabricated a skin sensor for the detection of various human motions.…”

Vitrimer composites: current status and future challenges

“…The increase of exchangeable aromatic disulfide content as previously reported in a CFRP, 51 and in dual covalent adaptable networks based on disulfide metathesis and transesterification, was also used in the context of MWCNTs. 66,67 The relaxation time of the composites at 200 °C was approximately 9 s without any catalyst, which is remarkably low and 3 cycles of continuous breaking/compression moulding did not alter the properties (Fig. 9).…”