Inductive Thermal Effect on Thermoplastic Nanocomposites with Magnetic Nanoparticles for Induced-Healing, Bonding and Debonding On-Demand Applications

Round 1

Reviewer 1 Report

Charitidis et al studied thermal effect such as heating capacity of composites based on iron particles and thermoplastic polymer matrixes. The polymer matrix studied were of 4 types and iron oxide varies from 2.5–10 wt%. Interesting results are reported and paper presentation is nice and informative. However, some revisions are required before acceptance for publication. Some points are –

[1] In introduction, more paper can be included based on iron oxide and other polymer matrix such as elastomers such as [a] https://doi.org/10.1007/s10965-022-03084-5, [b] https://doi.org/10.3390/polym13101550.

[2] Dispersion of iron oxide in different polymer matrix is critical in determining properties of composites. So, authors are encouraged to perform iron oxide dispersion in different types of polymers studied in this work. SEM/ TEM or AFM technique can be used.

[3] What do authors mean with bonding/de-bonding mechanism in the paper. Please elaborate?

Good Luck for revisions!

Author Response

Response to Reviewer 1 Comments

We would like to thank the reviewer for the positive feedback. Below, you may find the detailed responses to the comments:

Point 1: [1] In introduction, more paper can be included based on iron oxide and other polymer matrix such as elastomers such as [a] https://doi.org/10.1007/s10965-022-03084-5, [b] https://doi.org/10.3390/polym13101550.

Response 1: The two suggested references [17] and [18] and one additional [22] have been included in the Introduction.

Point 2: Dispersion of iron oxide in different polymer matrix is critical in determining properties of composites. So, authors are encouraged to perform iron oxide dispersion in different types of polymers studied in this work. SEM/ TEM or AFM technique can be used.

Response 2: Thank you for your suggestion. SEM / EDS mapping analysis for PA12 nanocomposites has been added indicatively, to evaluate the Fe3O4 particles dispersion, by detecting iron element. Since all nanocomposites have been prepared with a similar procedure, it is assumed that the same dispersion efficacy has been achieved for all polymers. SEM micrographs of the surface of the 3D printed PA12 have been added in Figure 4. For PEKK, which is a more demanding polymer, micro Computed Tomography (m-CT) has been carried out to assess the dispersion of the Fe3O4 particles in the polymer matrix. CTVox images of the scanned PEKK nanocomposites are included in Figure 5.

Point 3: What do authors mean with bonding/de-bonding mechanism in the paper. Please elaborate?

Response 3: In repair or recycling applications, it is often necessary to separate materials, often of dissimilar nature (for example, composites and aluminium). This is usually done via the application of large mechanical forces and extremely high temperatures, both of which can damage the parts and preclude their recovery. Thus, there is a need for easily dismantlable adhesive joints that can be separated with an external stimuli (debonding on-demand). The capability to achieve local debonding is advantageous when considering the Maintenance Repair and Operations (MRO) of multi-functional composite components. For example, it may be possible to detach and remove localised features, in order to implement smaller scale repairs. Additionally, the same capability may be deployed as part of the End of Life (EoL) disassembly procedure for recycling the individual parts. The disassembly process through induction heating technology is very promising for the development of de-bonding on-demand applications, supporting the MRO  in aerospace, automotive and other industries, in the frame of new repair and restoration techniques. The idea is to introduce a thin layer of thermoplastic iron oxide nanocomposite through Additive Manufacturing technologies, between two composite parts, to make easier the disassembly, both for conventional composite parts, but also for composite parts with new multifunctional architectures (e.g. those that have been manufactured by Additive Manufacturing Technologies or advanced composite manufacturing technologies, such as Automatic Tape Laying (ATL)). Additionally, the easy-to-disassembly operations allow to control the extent of damage and to reduce the related time and cost of the MRO and the remanufacturing of the required spare parts.

Reviewer 2 Report

Very well written Manuscript performed experiment very thoroughly described, and all data and assumptions for the experiment are given. The whole work ends with well-written conclusions.

My comments:

A photo of the 3D printer you used could possibly be included.

Ιmage 5 is there 2 times?

Perhaps a more detailed description of the experimental process should be made.

A question that can be asked to the editors is: Have you tested your material for mechanical properties?

The manuscript contains important scientific results.

Author Response

We would like to thank the reviewer for the positive feedback. Below there are the responses to the comments:

Point 1: A photo of the 3D printer you used could possibly be included.

Response 1: Figure 1 has been added which presents the 3D printer used within the study.

Point 2: Ιmage 5 is there 2 times?

Response 2: The image 5 replication has been removed.

Point 3: Perhaps a more detailed description of the experimental process should be made.

Response 3: Section 2.3 has been added in the manuscript which describes the dispersion assessment and further details have been given for the induction heating testing (now, Section 2.4).

Point 4: A question that can be asked to the editors is: Have you tested your material for mechanical properties?

Response 4: The testing of the mechanical properties of these specific nanocomposites was not within the scope of the current study. The polymers that have been used, are commercial available grades, with specific properties, that fulfill the requirements of the application. In future work, which is under preparation, mechanical properties assessment, together with an overall performance assessment are considered.

Point 5: The manuscript contains important scientific results.

Response 5: Thank you for the positive comment.