Graphite Nanoplatelets Nanostructured Films as Multifunctional Protective Layer in Kevlar/Nomex Sandwich Composites
, Barbara Palmieri 1,*, Giovangiuseppe Giusto 2,3, Ruggiero Volponi 2, Giovanni Bruno 2, Carmine Carandente Tartaglia 2, Cinzia Toscano 2, Michele Giordano 1 and Alfonso Martone 1,3,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsComments to the authors
The manuscript reports interesting results concerning the preparation of Kevlar/Nomex Sandwich Composites and studying the effects of Graphite Nanoplatelets on the nanocomposites. Synthesis of nanocomposites with enhanced properties has received increased attention in recent decades owing to their applications in various fields. The present work affords a promising strategy for designing such types of composites. The manuscript needs major revisions for quality enhancement, which are given below.
1. The manuscript contains grammatical and typing mistakes which should be carefully read and removed and the language needs improvement.
2. Discuss some applications of Graphite Nanoplatelets epoxy in the introduction section.
3. How were Graphite Nanoplatelets synthesized? Mention the chemicals used and their sources.
4. Check all the equations carefully for any mistakes.
5. Authors are suggested to check the mechanical properties of the composites.
6. Page 10, lines 268-269, the sentence is incomplete. Complete the sentence to demonstrate its meaning.
7. The authors should properly discuss the TGA data of the samples.
8. Discuss the obtained scientific results in the conclusion section.
Comments on the Quality of English LanguageThe language needs moderate editing.
Author Response
Thanks to the reviewer for the precious comments. Please see the attached file for detailed response.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe results of this study are presented in this publication in a way that is both clear and thorough, and they agree with the outcomes of the experiments. However, the originality of the work was not well explained or highlighted by the authors. After substantial modification, this work merits publication in this journal. The following concerns need to be resolved:
First, could you elaborate on the significance of using Kevlar/Nomex sandwich panels in the building of an engine nacelle and why they were selected for this study? What unique qualities make them suited for this application?
2. Describe the tapered core design, which has an angle of 18°3° and a footprint that varies in size from 140 x 140 mm2 on the bottom to 50 x 50 mm2 on the top. How does this layout affect the functionality of the panels when used in spacecraft?
3. could you elaborate on the top-down strategy and the spray deposition procedure used to create the GNP-rich films? How does the pre-impregnation with epoxy resin (Hexcel RTM6) at varying contents (10, 20, 30 wt%) impact the characteristics of the films?
4. The GNP-rich films, you say, are between 80 and 90 g/m2 in density and 70 to 6 m in thickness. How did you come up with the thickness and weight of these films? How do these factors affect their performance as barrier coatings?
5. When compared to an unprotected panel, the high filler content of the graphene films significantly slowed down and reduced moisture absorption (-71%). What implications do these results have for the aerospace industry, and in particular for aircraft components that must operate in damp conditions?
6. What did you find out from your research? Nanocomposites reinforced with Graphite NanoPlatelets (GNPs) at varied filler content levels (70, 80, and 90%wt) for Kevlar sandwich panels: can you offer data on the efficacy of protection against water uptake?
As such, I urge that it be published with significant changes.
Comments on the Quality of English Language
The English in the document should be revised by the native English to correct a few typos and grammar mistakes.
Author Response
Thanks to the reviewer for the precious comments. Please see the attached file for detailed response.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsGraphite Nanoplatelets Films as Multifunctional Protective 2 Layer in Kevlar/Nomex Sandwich Composites
The paper is well presented (and written) aiming at demonstrating how a 70 wt.% GnP-epoxy composite leads to a more effective moisture barrier than 80 and 90 wt.% GnP-epoxy samples. The experiments seem to be well carried out, which suggests that this result is interesting because it is counterintuitive.
However, I believe that the paper will be improved if the authors try to answer the following questions:
Þ I did not understand (the nice) Figure 7. It seems that the 90wt.% is a porous structure full of voids!? (The green area is large)
Þ How do you see voids on the SEM pictures !??
Þ What are these SEM picture : edge of the specimens ?
Þ How did you make the specimen for SEM ?
Þ At page 3 . 100 films are made by spray deposition process : how did you get the alignment of the nanoplatelets? How did you spray and cure the film? What was the diameter of the spray nozzle?
Figure 6 needs to be improved. The log graduations are missing, 1.0
I would suggest to add the weight fraction on the graph. (coherence with the rest of the manuscript)
Þ I do not understand why there are 4 compositions on this Figure ?
The legend : … with the volume fraction.
Þ metallic paints and PVF films are extensively used in aerospace applications thanks to their low permeability. The diffusivity is reduced by an order of magnitude with GNP. How many orders are obtained with metallic paints and PVF films??
All the paper : graphene should be replaced by GNP or GNP-epoxy composite. Nothing is given in the paper concerning the GNP geometry. From [29], it is 30 microns and 14 nm with a density of 2g/cm3. Concerning the volume fraction, (I checked and) it is calculated based on the filler density of 2 and the epoxy : 1.14. In the paper [29] I did not find any SEM image of the starting powders.
Þ What is the estimate % of particles with a thickness of 14 nm in the starting powder? I imagine that the powders are made of aggregates that cannot be destroyed during the process. The density of 2 is lower than the density of graphite : 2.3.
ÞWhy did you choose 2 for calculate the volume fraction from the weight fraction?
Some details :
Page 1. 37
….[1], the recycling phase of the composites remaining the key environmental issue.
Page 2. 54
… 2 wt.%... and 6wt.% (70°C) ….
Page 2. 69
…weight , and fragility
Page 2. 76
…. Because perfect graphene…
Page 2. 87
…. GAG…
Page 3 . 100
…with a monocomponent epoxy resin …
Page 3. Figure 1 Þ I am sorry. I do not understand the photo… Perhaps add some arrows and explain a little bit…
Page 4. 115/118/119
What does mean the 4 and 6 ?
Page 4. Figure 3 Þ I am sorry. I do not understand the photo… Perhaps add some arrows and explain a little bit…
Page 5. 157
Please add one or 2 sentences to explain how lock-in thermography works?
Page 6. 175
Add the unit: Ω.m ?
The accuracy of the resistivity in Table 4 is doubtfull…
Page 8 . 225
…impenetrable…
Page 8 . 229
Defined ed described
Page 8 . 230
AR = 2143 (30000/14)
Defined ed described
Table 6. …in GnP-epoxy composite
(With AR= 2143, the tortuosity is 601,815 and 901)
Page 9. 248
The nanostructure modifies being? problem
Page 9. 258
… nanoarchitecture…
Page 10. 270
… by increasing… ? problem with the sentence
Page 12. Figure 10 : Þ I do not understand the photo…
Figure 11 Resistance ordinates. What “T” stands for?
Page 13. 327
Explain what MU and GAG stand for. (avoid acronyms) M: moisture uptake ?
Page 13. 322
MU test ?
Page 14. Figure 14 and 15 Þ I do not understand the photo… but since I do not know GAG technique. I trust you !
Page 15. 362
…nanocomposite nanostructure…
Comments for author File: Comments.pdf
Author Response
Thanks to the reviewer for the precious comments. Please see the attached file for detailed response.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe authors had a valuable study on sandwich composites using nanoplatelets films.
The title is proper and comprehensive. However, if the final composite is in nano range, it can be reflected in the title.
In the abstract section: this section is well written. However, the introduction (background) section is so long and the conclusion section is not support the main results. Please re-write the abstract.
The introduction provides sufficient background and includes all relevant references. However, more recent and relevant references can be used. Besides, the main aims of the study and he gap of the study should be clear in it.
The cited references are relevant to the research. However, more recent and relevant references can be used.
The research design appropriate, however, please add the statistical methods. The valididty method, the sample size and its determination method,...
The result section is good.
The Figures and Tables are good in quality and quantity.
The discussion section can be improved using more potent studies. The comparison should be performed with recent studies as well.
Author Response
Thanks to the reviewer for the precious comments. Please see the attached file for detailed response.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript is sufficiently modified and can be accepted for publication.
Comments on the Quality of English LanguageThe manuscript only need minor spelling check.
Reviewer 2 Report
Comments and Suggestions for AuthorsI recommend the acceptance of the manuscript in the revised form
