Molecular Dynamics Study on the Synergistic Compatibilization Mechanism of MAH-g-SBS in Epoxy Asphalt
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsMolecular Dynamics Study on the Synergistic Compatibilization Mechanism of MAH-g-SBS in Epoxy Asphalt - Report
Manuscript is well structured, but there are a few important points to note:
- It is recommended to check the ordering (numbering) of the content titles.
- It is recommended to give more details about what Molecular dynamics simulation is, in the introduction section.
- In the simulations process, given methods such as Smart Minimizer method, Ewald summation approach should be explained in detail.
- It is recommended to switch analysis explanation parts to section experimental and simulation method instead of results and discussion section.
The article gives extensive coverage to molecular dynamics simulations, but the experimental part is quite limited.
The binding effect of MAH-g-SBS to polar and nonpolar phases due to its amphiphilic structure has been interpreted hypothetically. A more detailed interpretation is recommended.
The limitations of the parameters used when performing molecular dynamics simulations (e.g., cut-off distance, simulation time, initial density) are not discussed.
Table numbering is inconsistent; for example, Table 5 is presented twice with different content. Furthermore, the descriptions of some figures are too brief.
The paper clearly states its original contribution, but no comprehensive comparison is made with the results of similar simulation studies.
Author Response
We have provided a detailed point-by-point response to the reviewers’ comments in the attached Word file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis manuscript presents a molecular dynamics (MD) simulation-based study exploring how maleic anhydride-grafted styrene-butadiene-styrene (MAH-g-SBS) improves the compatibility between epoxy resin and asphalt. The study includes experimental validation via segregation tests and fluorescence microscopy. The combination of computational modeling and basic experimental work adds theoretical depth to the field of polymer-modified asphalts.
The research question is relevant, and the topic fits well within the scope of Coatings. However, while the work is promising and generally well-structured, it requires significant revisions in terms of novelty positioning, depth of analysis, and clarity of communication before being suitable for publication. This work can be published but the authors need to carefully address the following comments:
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The novelty claim is overstated. Previous studies have already examined compatibilizers (including MAH-modified SBS) in epoxy asphalt systems using MD simulations.
- Line 37: "between epoxy resin and asphalt": The authors need to cite the following recent work: https://doi.org/10.1080/10916466.2021.2017457
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The hypothesis (that MAH-g-SBS enhances compatibility through amphiphilic effects) is reasonable but not novel; it has been discussed in prior literature, including by the authors themselves.
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The manuscript lacks comparative benchmarking: How does MAH-g-SBS perform relative to other common compatibilizers (e.g., TPP, ESO)? Suggestion: Clarify what is truly new here. Is it the first RDF study of this system? Is the crosslinking method new? Otherwise, the contribution risks being incremental.
Crosslinking Reaction Model:
The process simulates curing between epoxy and anhydride, but does not address side reactions (e.g., incomplete reaction, steric hindrance).
The process simulates curing between epoxy and anhydride, but does not address side reactions (e.g., incomplete reaction, steric hindrance).
Suggestion: Discuss assumptions and limitations of the crosslinking model. Consider citing kinetic or reaction-path studies.
Simulation Reproducibility:
No mention is made of convergence checks, multiple runs, or standard deviations in computed properties. This affects reproducibility.
Suggestion: Report standard errors or repeat simulations for key outputs (CED, RDF).
Comments on the Quality of English Language
English quality needs improvement.
Author Response
We have provided a detailed point-by-point response to the reviewers’ comments in the attached Word file.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper on Molecular Dynamics Study on the Synergistic Compatibilization Mechanism of MAH-g-SBS in Epoxy Asphalt by P. Liu et al., presents a detailed study of the effects of MAH-g-SBS on the polymer-modified (Epoxy) asphalt.
The paper is nicely written and presented, with high quality figures and a clear discussion. However, there are aspects that hinder the purpose of the paper.
The Authors prepared some samples. However it should be noted that:
1. the mixing components are not specified quantitatively: either it is a (industrial) protection issue or it is of no interest in the paper (?!)
(L114 ...prepared according to predetermined mass ratios of epoxy resin, curing agent, modifier, and base asphalt)
2. The only result presented about the samples is the fluorescence imaging (Figure 10).
All the paper is about the presentation of (many) different parameters obtained with the theoretical model, with no reference to any experimental data or comparison of model and experiment. Thus, Section 2.1 is confusing since it is not clearly declared what is the reason for making samples. Indeed, in reference to point 1, there is no (model) evaluation on the effects caused by different mixing proportions.
Moreover, the Authors conclude (L421): By integrating simulation and experimentation, this work aims to promote... However there is no experimental data integrated in this paper.
Therefore, it is very important that the Authors make a clear statement about the reach of the 'experimental part' of the paper, otherwise being very confusing.
Besides that question, the theoretical analysis and presentation is fine. But still, one important question is about the model itself: how much the model depends on the Authors? Is the molecular software tool a framework that can work with a simple input? Or is it heavily based on previous results about the same molecules? Or, do the Authors program (many) details of the molecular dynamics? This has to be clearly stated to fully understand the complexity (or not) of developing such a model and obtaining detailed results.
Typos, please check:
L225 ....The results are presented in Table 3... Table 5?
L 257 ... As shown in Table 4... Table 6?
Figure 10: flipped a and b panels ? (According to the text)
Author Response
We have provided a detailed point-by-point response to the reviewers’ comments in the attached Word file.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have rigorously addressed all my comments and concerns satisfactorily.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe Reviewer appreciates the positive answer of the Authors to discuss the raised questions.
The Authors have considered all the comments and questions raised during the review process, providing sound answers and including the right information in the new version of the paper.
