**5. Conclusions**

In this work, it was demonstrated that resistance heating via an electrically conductive MWCNT/PP film at the welded interface facilitated ultrasonic joint disassembly of TPCs. Three MWCNT fractions were characterized for thermo-electrical behavior with applied voltages up to 10V. A maximum temperature of 120 ◦C was reached at the highest MWCNT loading and applied voltage. For disassembly experiments, tests were initiated when the surface temperature of the GF/PP adherend reached either 110 ◦C, 130 ◦C or 150 ◦C. The shear stress during disassembly decreased by at least 93% at the highest MWCNT weight fraction and surface temperature, compared to room temperature testing. Analysis of fracture surfaces after disassembly revealed the melting of both MWCNT films and the adherends' matrix at the overlap with significant matrix drawing and fiber–matrix debonding, effectively facilitating disassembly. At higher temperatures and MWCNT weight fractions, the heat-affected zone extended through the thickness of the adherends, owing to the low cross-head speed and the duration of the disassembly phase (<120 s) during which heat transfer occurred. In order to minimize the extent of the heat-affected zone area (<60%), while maximizing ease of assembly, a surface temperature of 130 ◦C with 20 wt.% MWCNT films would be recommended for the parameters investigated in this study.

Overall, this study confirmed the feasibility of this disassembly method for the first time in the literature. However, this might be better suited for recycling at end-of-life or reuse of components by cutting off the heat-affected overlap section. Moreover, as the interface was structurally compromised during disassembly, it affected the efficiency of resistance heating. Faster crosshead speeds during disassembly, the use of the highest MWCNT weight fractions, and control of the applied voltage during the process could, however, mitigate these limitations.

**Author Contributions:** Conceptualization, H.F. and G.P.; funding acquisition, G.P.; methodology, analysis and investigation, H.F. and W.L.; validation, H.F. and G.P.; writing—original draft preparation, H.F. and G.P.; writing—review and editing, G.P. and W.L.; visualization, H.F., G.P. and W.L.; supervision, G.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Louisiana Board of Regents under the Research Competitiveness Subprogram (contract number LEQSF (2018-2022)-RD-A-05) with partial funding from the LaSPACE Research Enhancement Award (award number 002379) and the LSU Graduate School Economic Development Assistantship.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** The authors would like to acknowledge Mark Brennan for his assistance with tensile tests.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
