Review Reports

Round 1

Reviewer 1 Report

Revision of jcs-2182988

This work focuses on aging studies of wood-plastics composites (WPC) through the assessment of its structural, thermal and mechanical properties. The topic is interesting and relevant from a commercial and engineering point of view. However, the article has serious flaws in the presentation and discussion of the results, which will be explained below and commented on in the attached document, which makes its publication in the Journal of Composites Science unfeasible. In this sense, I recommend Reject.

 

Comments/Suggestions:

The writing of the article is careless with many spelling mistakes in the units, in the reference to figures, in the presentation of graphics, and even with duplicated paragraphs.

The authors make reference to tables and data that do not exist in the document.

The data of some figures are not even referred (e.g. figure 3) or discussed in the text, and much of the information is just presented and not discussed.

The introduction section is poor in terms of state of the art and provision of comparative data.

 

In short, despite considering that the research topic has value and scientific interest, the manuscript needs to be greatly improved in order to be considered for publication. The authors mention in the introduction that this article is the 1^st part of the work, I recommend adding the 2nd part to make the article more complete and more scientifically relevant.

 

The article with comments throughout the document has been attached.

Comments for author File: Comments.pdf

Author Response

1. All corrections are made in the revised manuscript.
2. The data and tables were submitted as separate attachments. However, we have now incorporated them into the revised manuscript.
3. All data from tables and figures are referred and discussed in the revised text.
4. Introduction section is revised and resubmitted.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript mainly dicussed the mechanical properties of the WPCs based on HDPE and PP with varied wood fiber content. Overall, the content is not too adequate and there are some parts need to be improved.

1. Abstract is too short, the results, Important refinement results are missing.

2.  In the end of the introduction part, the Innovative points should be pointed out by the author.

3. Experimental part. 50% wood fiber should be checked. PE should be corrected to HDPE. How to apply the compatibilizer and how many samples were tested under the same condition  and so on. this part missed a lot details.

4. where are the table 1 and table 2.

5. Figure 1 and figure 2. every subfigures should have its lable. and figure 1 the FTIR Y axis commonly should not include value. figure 1 showed the results may not consistent with your discussion which should be rewritten to more clearly illustrate.

6. figure 4, What can be seen from the pictures is very limited. change the figures or zoomed to stay in the focus of your discussion.

Author Response

1. Abstract section is revised to reflect the study undertaken and its findings.
2. We have added relevant points under introduction section.
3. Detailed information in the experimental and sample preparation sections are added.
4. The tables were submitted as separate attachments. However, we have now incorporated them into the revised manuscript.
5. All figures and tables are labelled appropriately and results/discussion section has been rewritten accordingly.
6. Images in figure 4 are updated to higher magnification microscopic images.

Author Response File: Author Response.pdf

Reviewer 3 Report

SUMMARY

The article submitted for review is devoted to a topical issue. The durability of wood-plastic composites based on HDPE and PP and the mechanical properties of composite materials are considered. The relevance of the study is justified by the fact that such materials are very promising and applicable in modern engineering areas. This is justified by the fact that they have sufficiently high physical and mechanical properties that allow them to be operated with high efficiency. The scientific purpose of the study is devoted to a detailed study of properties with the help of experiment and analytics. Thus, the study is important from the point of view of science and practice, and is sufficiently original. However, it has a number of serious drawbacks, they are listed below.

 

COMMENTS

1.    The authors put the abbreviations HDPE and PP in the title of the article. Probably, these abbreviations should have been fully deciphered in the title, followed by a transition to them in the text of the article itself. The fact is that many readers may not understand the meaning of these abbreviations, for example, those readers who are not specialists in the field of wood-plastic composites.

2.    The next remark concerns the abstract. The fact is that it does not meet the requirements of the journal. First, it is too small in size. Secondly, it lacks the formulation of a scientific problem. The authors immediately begin to tell that wood-plastic composites based on polymers with different wood content were obtained, but do not explain why this was done. The abstract should begin with the formulation of the scientific problem. The authors conclude the abstract by discussing differences in mechanical properties, in changing the modulus of elasticity, but there is no quantitative expression of the result and there is no clear formulation of the scientific result. If the authors aimed at the research nature of the article, without having an applied, practical purpose, then this should also be reflected. The novelty in this case will be only scientific, since certain new fundamental knowledge about the properties of materials will be obtained depending on its composition. But then, perhaps, the whole concept of the article should be reworked. The authors need to reflect both the scientific result and the practical result, if any.

3.    In the "Introduction" section, the literature review is very poor. The authors considered a total of 15 references. A note is, in addition to the small amount of literature studied, also the location of the links in the wrong order. This makes it difficult for the reviewer and the reader to understand. Authors should revise the numbering of references in order to clearly structure the literature review.

4.    Literature review should end with a clear formulation of the scientific problem, scientific novelty, purpose and tasks of the study.

5.    The lack of a program of experimental research is noteworthy. The authors provide an "Experimental" section, but it is quite small and should probably be called "Materials and Methods". The authors say very little about the materials and the choice of methods and materials is unreasonable.

6.    The section "Results and Discussion" also needs serious improvement. Figures 1 and 2 take up a lot of space, but they are poorly explained. There is no smooth transition between sections 2 and 3.

7.    Sections are not numbered, which makes it difficult for readers to review and understand.

8.    Figure 3 looks uninformative, because almost direct dependences are obtained, but this effect is poorly explained. In addition, a small number of points of variation attracts attention. Such a small set of experimental data suggests that, probably, the dependence may have a different character. The authors should also study other percentages of the filler so that the dependence has a brighter, more pronounced character and can be more correct.

9.    Figure 4 is presented in poor quality, captions are indistinguishable. Authors need to submit it in the proper quality.

10.  There is not enough discussion of the obtained results, there is no comparison of these results with the results of other authors. The scientific novelty is not clear from this.

11.  The conclusions should also be supplemented, concretized in the direction of a clear formulation of the scientific result and prospects for the development of the study.

12.  15 references for such a topic as wood-plastic materials are very few. The authors had to consider at least 30-35 references.

13.  In general, the reviewer's comment on the article is that in its present form it is not ready for publication. It is necessary to seriously refine, increase and strengthen the analytical part and give it a scientific character. In its current form, the article cannot be published in the journal and needs serious revision.

Comments for author File: Comments.pdf

Author Response

We have added full form for all abbreviations and defined them before using in text.

We have revised the whole manuscript taking into consideration all the comments and remarks made by the reviewers and consistent with our findings.

Introduction section has been updated with new and relevant references added with proper numbering and citations.

We have updated the literature review and explained in greater detail the scientific problem and purpose of this study.

Reviewer’s comment on the experimental, materials, and its choice is explained in the revised text.

Results and Discussion section is also updated to reflect our findings and correlated with the already existing literature on this topic.

We have explained the figure 3 and its data in more detail in the revised text and also clarified the variations (where ever applicable).

Figure 4 is revised with better quality and higher magnification images.

Discussion is updated to reflect our findings and correlated with other findings from literature.

Conclusions are now updated with clear description of our findings and suggestions where ever required.

We have added the number of references with most relevant and latest studies on this topic.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Revision of jcs-2182988_Round#2

Dear authors,

you have improved the quality of the document, taking into account the suggestions, and corrected some of the serious flaws of the first version. However, in my opinion, the article still has serious gaps that prevent its publication in the Journal of Composites Science. In this sense, I recommend Reconsider after major revision.

 

Comments/Suggestions:

As with the first review, I made comments throughout the document with suggested corrections and some pertinent questions, that I would like to see resolved in order to propose the article for publication. Again, I ask you to be more careful with the writing and with the details of presenting results in accordance with the standards of a scientific document. List the most relevant comments below:

 

1. In Figure 1b is possible to observe that the control sample of PP presents an absorption peak around 3500 cm^-1 (blue curve). However, the authors state that this absorption does not occur. Please review the information and justify your statement.

2. In the line 149 the authors state that the changes in FTIR and DSC spectra “suggest that the wood fibres and the polymer were intimately mixed in the composite”. What kind of modifications are you referring to?

3. In lines 167 and 168 it is mentioned that for lower percentages of wood fibres the decrease in Mn is not significant. What happened to the higher percentages?

4. Why the PDI values (Table 1) are higher than 1? Please justify this unexpected value.

5. Between lines 193 and 196 the SEM results are presented and discussed, which only appear in the last figure of the document (Figure 4). It makes no sense to carry out this analysis when Figure 3 and Table 2, that appear before, have not yet been discussed. In my opinion the SEM images should be presented right at the beginning of the discussion, in Figure 1 therefore.

6. Please comment on the high value of the standard deviation for the elasticity modulus.

7. Between lines 220 and 223, the authors refer to screw temperature as a reason for lower viscosity and inferior properties of PP composites. However, the elastic modulus of PP composites are higher than those of HDPE. Please clarify what you mean.

8. Please reorganize the “results and discussion”. Reorder the data presentation sequence to create a logical thread and interconnect the discussion of all results.

 

Please attend to all comments in the manuscript and not just the most relevant ones presented here. The manuscript with comments has been attached.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer Comments:

Dear authors,

you have improved the quality of the document, taking into account the suggestions, and corrected some of the serious flaws of the first version. However, in my opinion, the article still has serious gaps that prevent its publication in the Journal of Composites Science. In this sense, I recommend Reconsider after major revision.

 Comments/Suggestions:

As with the first review, I made comments throughout the document with suggested corrections and some pertinent questions, that I would like to see resolved in order to propose the article for publication. Again, I ask you to be more careful with the writing and with the details of presenting results in accordance with the standards of a scientific document. List the most relevant comments below:

1. In Figure 1b is possible to observe that the control sample of PP presents an absorption peak around 3500 cm^-1 (blue curve). However, the authors state that this absorption does not occur. Please review the information and justify your statement.

We have reviewed the section and agree with the reviewer. The statement is now changed to reflect that the absorption does occur.

 

2. In the line 149 the authors state that the changes in FTIR and DSC spectra “suggest that the wood fibres and the polymer were intimately mixed in the composite”. What kind of modifications are you referring to?

We have now included and explanatory statement to explain why the spectra suggests good mixing of wood and polymer components.

 

3. In lines 167 and 168 it is mentioned that for lower percentages of wood fibres the decrease in Mn is not significant. What happened to the higher percentages?

We carried out average molecular weight determinations for only the low-wood fiber composite. This is now stated in the manuscript.

 

4. Why the PDI values (Table 1) are higher than 1? Please justify this unexpected value.

We do not agree with the reviewer. Having a PDI of >1 is not unusual for polymers. This is to be expected.  We have added a statement to show that PDI is a measure of the broadness of the molecular weight distribution.

 

5. Between lines 193 and 196 the SEM results are presented and discussed, which only appear in the last figure of the document (Figure 4). It makes no sense to carry out this analysis when Figure 3 and Table 2, that appear before, have not yet been discussed. In my opinion the SEM images should be presented right at the beginning of the discussion, in Figure 1 therefore.

We agree with the reviewer and changed the position of figure 4 and changed the numbering of the figures.

 

6. Please comment on the high value of the standard deviation for the elasticity modulus.

We have not further discussed it. Only speculative explanations are possible as the data we have does not suggest an explanation for the difference in standard errors. But, it is important to document that the standard error is large.

 

7. Between lines 220 and 223, the authors refer to screw temperature as a reason for lower viscosity and inferior properties of PP composites. However, the elastic modulus of PP composites are higher than those of HDPE. Please clarify what you mean.

We have added a sentence to further explain why the modulus of PP does not show inferior values while other measures do.

 

8. Please reorganize the “results and discussion”. Reorder the data presentation sequence to create a logical thread and interconnect the discussion of all results.

We believe that the improved manuscript has a logical thread and explores the interconnection between results.

 

Reviewer 2 Report

The authors have made detailed revisions based on the comments, and the quality of the paper has improved greatly.

Author Response

Reviewer Comment:

The authors have made detailed revisions based on the comments, and the quality of the paper has improved greatly.

No reply from authors.

Reviewer 3 Report

The authors took into account all the wishes of the reviewer and responded to all comments. The reviewer is satisfied. The article may be published.

Author Response

Reviewer Comment:

The authors took into account all the wishes of the reviewer and responded to all comments. The reviewer is satisfied. The article may be published.

No reply from authors.

Round 3

Reviewer 1 Report

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