Analysis of the Degradation During Melt Processing of PLA/Biosilicate^® Composites

Round 1

Reviewer 1 Report

The authors submitted the article entitled “Analysis of the degradation during melt processing 2 of PLA/Biosilicate composites”. I would recommend that the paper could be published elsewhere. My main comments and questions are as follows:
1. Overall, the motivation is trivial. It has been reported about the degradation during melt processing PLA. The only discussion about the presence of Biosilicate cannot match the scope of the journal.
2. The introduction should add previous literature about the degradation during melt processing PLA.
3. The data are scientifically insufficient and insignificant. The authors should provide more solid data, such as NMR, XRD, DSC, and so on to have more direct proof of the degradation.
4. TGA profiles should be provided.
5. Instruments in Characterization part did not match in the Results and discussion.
6. English correction is recommended.

Author Response

Response to Reviewer 1

 

R: We are so grateful for the valuable comments about our study. All your contributions are been accepted.

The authors submitted the article entitled “Analysis of the degradation during melt processing 2 of PLA/Biosilicate composites”. I would recommend that the paper could be published elsewhere. My main comments and questions are as follows:
1. Overall, the motivation is trivial. It has been reported about the degradation during melt processing PLA. The only discussion about the presence of Biosilicate cannot match the scope of the journal.

R: The preparation of biocomposites of PLA with Biosilicate® is a new path for the preparation of new biomaterials. Several research groups are studying the effectiveness of the production of this biocomposite for the production of scaffolds. The main difference of this work compared to the literature consists in the fact of the processing of filaments for the production of scaffolds by 3D printing, for that it is necessary for the preparation of the filament. In this work we are showing the difficulty for this production.

2. The introduction should add previous literature about the degradation during melt processing PLA.

R: The introduction has been improved and new references have been added.

3. The data are scientifically insufficient and insignificant. The authors should provide more solid data, such as NMR, XRD, DSC, and so on to have more direct proof of the degradation. 

R: At this moment we provide the DSC curves to aid in the explanation of the degradation process of PLA in contact with the Biosilicate®. We understand that a much more rigorous evaluation can be made, but the results obtained until the present moment show the effect that the authors wish to present, mainly related to the difficulty of processing.

4. TGA profiles should be provided. 

R: The TGA profiles were added.

5. Instruments in Characterization part did not match in the Results and discussion.

R: An extensive verification was carried out for the entire methodology to be considered.

 6. English correction is recommended.

R: The English were checked.

 

Reviewer 2 Report

Please see the attachment.

Comments for author File: Comments.pdf

Author Response

R: We are so grateful for the valuable comments about our study. All your contributions are been accepted.

The manuscript entitled “Analysis of the degradation during melt processing 2 of PLA/Biosilicate composites” by Eduardo Backes et al. covers the important problem of development of bioactive glass-ceramics and their characterization. The processability of two different polylactides with 1wt% addition of biosilicate was performed. The obtained materials were tested by thermogravimetric analysis, gel permeation chromatography. Also, zeta potential and rheological tests were performed. Despite that, the article is generally well written and the overall topic is interested in the readers, several major changes and additional discussion should be implemented in the submitted manuscript

 

Please consider: - the Abstract should be a concise description of the results, please rewrite the abstract and try to comment on all results that were.

R: The abstract has been modified and improved.

 - there is a lack of experimental curves of TG and DSC in the paper. The shape, intensity of the observed signals is extremely important in the discussion part.

R: The experimental curves of TGA and DSC were added and the image quality improved.

Moreover, the overall discussion of the TG should be performed, including DTG signals which are also very informative. Also, the solid residue amount should be commented on.

R: The DTG signals were added and the discussion was improved.

The temperature in Table 2 should be presented in form of an integer.

R: Table 2 was corrected

The tests under oxidative should be performed in order to compare the thermal stability of the materials under experiments with those under processing.

R: We agree that this test may help in the discussion, but in this work we check the effect of the material after the process and already degraded. An oxidizing atmosphere could camouflage the effect of the process, further increasing the degradation during the test.

The authors should discuss the change in the glass transition after reheating of the material in DSC measurement (the difference between Tg from the first and second heating scan).

R: Since the author would like to analyze the influence of Biosilicate® addition in the composition we considered more suitable to analyze only the second heating, i.e., after erasing the thermal history of the materials. A deeper discussion about the thermal properties was also added to the manuscript.

- the experimental part should be completed with the proper tests description as crucible size and type - on page 7 authors wrote that “PLA 2003D presented acid content of 0.20 ± 0.02 while PLA 4043 0.30 ± 0.01 [15,16].”

R: The information was added.

– it this not clear for the reader that authors performed these tests or them just the results

R: The text has been checked to make it clearer.

 - why only one biosilicate amount was considered in the experimental part, how it was chosen - the conclusion part should be expanded.

R: Preliminary tests were done with a small content of filler based on the experience of the research group. Other amounts of Biosilicate® were expected to be used, however, with a small amount already several degrees of degradation was observed. The increase in this content would only accelerate degradation. Comments have been added in the text.

 

Reviewer 3 Report

The aim of the study was to the development of melt-processed PLA/Biosilicate® composites to produce composites with bioactive properties. The manuscript is well written but contains a lot of spelling and typing mistakes.

Thermal characteristics by DSC of the obtained materials is missing. Evaluation of changes in the thermal properties of the tested samples as a consequence of the thermal history during processing should correlate with the molar mass changes, and may be helpful in explaining changes in the color of the PLA matrix. I recommend also extending the Introduction in the context of the research carried out and novelty of the work.

Some spelling and typing mistakes:

Abstract:

“Biosilicate” is a trade name and should be write with ® - “Biosilicate®”. Please correct throughout the text.

Please check the spelling throughout the text, e.g.:

“Poly (lactic acid)” poly should be written without a space,

“thermo degradation” is one word (6 times in the text),

“Tonset” italics and onset should be written as subscript (T_onset) (4 times in the text),

“g / mol”, “wt %”, “mL / min” should be written without a space (g/mol, wt%)

“0.05M” should be written with a space (0.05 M).

Line 58: “and was produced via and” – In this sentence something is missing.

Equation 1: All variables (such as V_e) should be written in italic. Please correct the entire text.
Please give abbreviation of the acid group in English word order “ag”.

Line 80: “ma” a should be written as subscript.

Line 80, 92, 93 and 88: “-1” should be written as superscript.

Line 87 and 88: “° C” should be written without a space.

Line 88: “N2”; 2 should be written as subscript. Also line 90 and 93: T_g

Line 95: What is “CM”?

Line 96: “50°C”; space after 50.

Line 100 and 102 Please write “1 (a)”and 1(b) in the same way.

Line 115: There was probably a mistake in the unit.

Line 130 and 132: “Fan” and “Fan et al. (13)” Is this the same citation?

Line 148, 150, 151, 159, 171, 187, Table 1: “Mw” and “Mn”; Please correct.

Table 1: “Mn/Mw (g/mol” missing bracket. Please correct.

Table 2: Use the dots instead of the commas,

“40431wt%”; two spaces are missing,

“2003d 1wt%”one space is missing, D should be in capital letter.

Author Response

Response to Reviewer 3

 

R: We are so grateful for the valuable comments about our study. All your contributions are been accepted.

The aim of the study was to the development of melt-processed PLA/Biosilicate® composites to produce composites with bioactive properties. The manuscript is well written but contains a lot of spelling and typing mistakes.

Thermal characteristics by DSC of the obtained materials are missing. Evaluation of changes in the thermal properties of the tested samples as a consequence of the thermal history during processing should correlate with the molar mass changes and may be helpful in explaining changes in the color of the PLA matrix. I recommend also extending the Introduction in the context of the research carried out and novelty of the work.

R: DSC analyzes were added and correlated with the other techniques used.

Some spelling and typing mistakes:

R: All the spelling and typing mistakes were corrected.

Abstract:

“Biosilicate” is a trade name and should be written with ® - “Biosilicate®”. Please correct throughout the text.

Please check the spelling throughout the text, e.g.:

“Poly (lactic acid)” poly should be written without a space. Corrected

“thermo degradation” is one word (6 times in the text), Corrected

“Tonset” italics and onset should be written as subscript (T_onset) (4 times in the text), Corrected

“g / mol”, “wt %”, “mL / min” should be written without a space (g/mol, wt%) Corrected

“0.05M” should be written with a space (0.05 M). Corrected

Line 58: “and was produced via and” – In this sentence something is missing. Corrected

Equation 1: All variables (such as V_e) should be written in italic. Please correct the entire text.
Please give abbreviation of the acid group in English word order “ag”. Corrected

Line 80: “ma” a should be written as subscript. Corrected

Line 80, 92, 93 and 88: “-1” should be written as superscript. Corrected

Line 87 and 88: “° C” should be written without a space. Corrected

Line 88: “N2”; 2 should be written as subscript. Also line 90 and 93: T_g Corrected

Line 95: What is “CM”? Corrected

Line 96: “50°C”; space after 50. Corrected

Line 100 and 102 Please write “1 (a)”and 1(b) in the same way. Corrected

Line 115: There was probably a mistake in the unit.  Corrected: Torque is Newton.Meter

Line 130 and 132: “Fan” and “Fan et al. (13)” Is this the same citation? Yes, and the sentences was corrected

Line 148, 150, 151, 159, 171, 187, Table 1: “Mw” and “Mn”; Please correct. Corrected

Table 1: “Mn/Mw (g/mol” missing bracket. Please correct. Corrected

Table 2: Use the dots instead of the commas, Corrected

“40431wt%”; two spaces are missing, Corrected

“2003d 1wt%”one space is missing, D should be in capital letter. Corrected

 

Reviewer 4 Report

The content of the manuscript is valuable and will help a lot of researchers out there. Nonetheless, the quality of the work needs improvement. The English needs to be improved in some places. The following specific parts requiring improvement are:

The introduction is good but the reason for selecting this study is weak. A stronger argument and proof is required to emphasise on the importance of this work. Read more papers and add justification to why this specific method was used and why you think it is going to help.

Zeta potential is a way of characterisation and hence is not part of the 'preparation of PLA/Biosilicate composites'

The methods chosen are good but maybe presented differently. At the moment it feels that you are just stating the tests you are doing, For a good paper, a justification for each test can be helpful. And add a flow to the materials and methods subsection. 

Results and Discussion is supposed to be the main part of the paper but in this case, it is the weakest. Introduce the section first. Talk about the outcome of the mixing process and what was obtained. Explain the origin of the data in figure 1. How was it obtained? Did you use the values obtained as it was? How did you obtain the graph? If it is too much methods, then instead of mentioning these in the results section, mention these in the methods section. At the moment, a reader will be confused. Furthermore, all figures needs toi be labelled according to the different parts of the figure itself. Any figure placed in the manuscript needs to have a meaning in the paper. They needs to be explained well and associated to the results in this work. 

Conclusion will be better once the previous sections are improved. Again a stronger case is required for the importance of this paper and the results need to be presented in a way that is impactful. 

More references required which will add more value to the latter work. 

Comments for author File: Comments.pdf

Author Response

 

Response to Reviewer 4

 

R: We are so grateful for valuable comments about our study. All your contributions are been accepted.

The content of the manuscript is valuable and will help a lot of researchers out there. Nonetheless, the quality of work needs improvement. English need to be improved in some places. The following specific parts requiring improvement are:

The introduction is good but the reason for selecting this study is weak. A stronger argument and proof is required to emphasize the importance of this work. Read more papers and add justification to why this specific method was used and why you think it is going to help.

R: The introduction was modified and improved, the use of this material was explained. Other references have been added to complement the introduction.

Zeta potential is a way of characterization and hence is not part of the 'preparation of PLA/Biosilicate composites'

R: The zeta potential characterization was added in the new section.

The methods chosen are good but maybe presented differently. At the moment it feels that you are just stating the tests you are doing, For a good paper, a justification for each test can be helpful. And add a flow to the materials and methods subsection. 

R: The methodology was changed and in each case the use of the technique was explained.

Results and Discussion is supposed to be the main part of the paper but in this case, it is the weakest. Introduce the section first. Talk about the outcome of the mixing process and what was obtained. Explain the origin of the data in figure 1. How was it obtained? Did you use the values obtained as it was? How did you obtain the graph? If it is too much methods, then instead of mentioning these in the results section, mention these in the methods section. At the moment, a reader will be confused. Furthermore, all figures needs to be labeled according to the different parts of the figure itself. Any figure placed in the manuscript needs to have a meaning in the paper. They needs to be explained well and associated to the results in this work. 

R: The discussion was reorganized and all points were considered.

Conclusion will be better once the previous sections are improved. Again a stronger case is required for the importance of this paper and the results need to be presented in a way that is impactful. 

R: The conclusion has been improved.

More references required which will add more value to the latter work.

R: New references were added.

 

Round 2

Reviewer 1 Report

The article has revised in an excellent manner.

Author Response

We are so grateful for the valuable comments about our study.

Reviewer 2 Report

The reviewer accept the authors explanation. The paper after revision looks much better, but still it needs some corrections, there are several mistakes which should be corrected before next submission. The reviewer suggest to check the paper with the editor built in the text processing tool (Office Word or other), it will help to see the small mistakes with spelling or other.

Moreover, please consider:

1. page 1, line 23: "the composites ere characterized" - the composites were characterized

2. Page 1, line 27: “PLA 4043” – PLA 4043D

3. please consider to reword sentence page 2 line 80-83, especially "has potential to be applied in antibacterial…", "It is interesting to point that .."

4. page 2 line 82: " propetie of Biosilicate(R).." - "properties of Biosilicate(R).."

5. page 2, line 83: please explain what is "45S5"

6. page 2, line 95 "In vitro" - in vitro

7. page 2, line 97-98: "further bioactive properties was assessed with cell lines cutlures. T the authors..." - "further bioactive properties were assessed with cell lines cultures. The authors.."

8.page 2, line 102: „The main disadvantage of these processes..” – which processes?

9. please reword page 2, line 107-109

10. page 2, line 123-124: “[6-9][Characterization and In Vivo Biological Performance of Biosilicate RENNO]” – please correct

11. please check page 3 lines 165 and 167: “185 ºC.”

12. page 3, line 193-194: “The samples were heated from room temperature at 750 °C, a heating rate of 20 °C/min under N2 atmosphere in a TA Instruments equipment, model TGA Q50” – The samples were heated from room temperature to 750 at a heating rate of 20 under nitrogen atmosphere in a TGAQ50 (TA Instruments).”What kind of crucibles was used?

13. page 3, line 201: “crystalline PLA [1] apparent degree” – “crystalline PLA [1]. The apparent degree..”

14. page 4, line 248: “crystalline PLA [1] apparent degree” – you can omit this information, while the Bioglass doesn’t melt in this temperature range. Please be careful with the parameters assignments, such as ΔH_m° in the text and the equation.

15. page 4 line 256 and other: please check the unit for torque, which is Nm, N·m, not N.m

16. page 4 line 266-269: “The literature shows that the main reaction of the thermo-oxidative degradation mechanism of PLA (neat) is non-radical with intramolecular transesterification. The reactions involved during the thermal degradation of PLA are non-radical, backbiting ester interchange, cis-elimination and they are dependent of the hydroxyl groups at end of PLA chain” – what is non-radical? Non-radical scission? It should be precisely written. The reactions are dependent on the presence of OH groups, that influence on ..

17. page 4, line 272:’ “These reactions occurs..” – occur

18. page 4, line 275: “in Figure 2 that presents both PLA after been processed in internal mixer” - in Figure 2 that presents the visual appearance of both PLA after processing in internal mixer

19. page 5 line 328: “test was performed in the Biosilicate® [17] and the result is show in” - test was performed for the Biosilicate® [17] and the result is showed in..

20. page 6 line 360: “Fan et al. [18,19] prepared PLA calcium ion end capped (PLA-Ca)” – please correct are they PLA-Ca composites?

21. page 7 line 384-386: “although the Biosilicate® reduced the viscosity of both PLAs remarkably. The viscosity variation presented by both composites was equivalent when compared to the pure polymers.” – maybe better: “The presence of Biosilicate® reduced the viscosity of both PLAs remarkably, although the viscosity variation presented by both composites remained equivalent when compared to the pure polymers”

22. page 7 line 388: “(0,01)” – please correct 0.01

23. page 8 line 407-408: “Table 1 presents Mn and Mw of the same materials.” – please correct and leave just (Table 1)

24. page 8 line 414” “when compared to their pellets..” – to its pellets

25. page 8 line 415-416: “In order to investigate the different behavior presented for the PLAs their residual acid content (RAC) were determined.” – “In order to investigate the different behavior of the PLAs their residual acid content (RAC) values were determined”

26. page 9 line 494: “The influence of PLA degradation was analyzed through thermal stability using TGA and DSC” - “The influence of PLA degradation was analyzed through thermal stability using TGA, while their thermal behavior before decomposition was registered in DSC”

27. page 9 line 505: “that during the temperature of analysis are not decomposed.”- “that under TGA test conditions are not decomposed.”

The next sentence should be reword or explained, what kind of reactions? Now it is opposite to the statement about solid residue in TGA. Why the amount of solid residue is higher than bioglass addition? It should be commented. Better to present TGA and DTG curves comparison than single curves, so please correct and show just two figures with PLA 2003D and 4043D materials, respectively. Please correct the axis units (TGA and DTG).

28. Please reword the DSC discussion page 10 line 561-562 “The curve of the second heating of all samples shows that PLA was kept almost constant, approximately 60 ° C”,  line 560-575, especially line 571-573 “PLA when crystallized in the temperature range from 100 to 120 ºC can be formed crystals  α and α’ at the same time [23]. PLA 4043D and its composite was observed one shoulder at the peak fusion of PLA.” , line 575 ‘which is subsequently fused to higher”, line 592 “mass and the presence of Bioglass”, 593 “during crystallization in the composite cooling”,

29. There is a change in the crystallinity degree for the composites, please add the proper comments to those already existing (page 11 line 592-599), Line 605: “Curves are displaced vertically for clarity” – curves were translated and presented vertically for clarity. Please correct also the Conclusions page 11 line 615-616,

30. Please check: page 12 lines 668, 670, ref 7 and 9 “Biosilicate ®®”, line 709 ref 21 “Polym. Degrad. Stab. ! 1996”, line 693/694 ref 14 and 15, line 716 ref 25

 

Author Response

Response to Reviewer 2

 

R: We are so grateful for the valuable comments about our study. All your contributions have been accepted. The numbers were not matching exactly the text, if necessary I can further correct minor mistakes.

Moreover, please consider:

 

1. page 1, line 23: "the composites ere characterized" - the composites were characterized Corrected

 

2. Page 1, line 27: “PLA 4043” – PLA 4043D Corrected

 

3. please consider to reword sentence page 2 line 80-83, especially "has potential to be applied in antibacterial…", "It is interesting to point that .." Corrected

 

4. page 2 line 82: " propetie of Biosilicate(R).." - "properties of Biosilicate(R).." Corrected

 

5. page 2, line 83: please explain what is "45S5" Corrected

 

6. page 2, line 95 "In vitro" - in vitro Corrected

 

7. page 2, line 97-98: "further bioactive properties was assessed with cell lines cutlures. T the authors..." - "further bioactive properties were assessed with cell lines cultures. The authors.." Corrected

 

8.page 2, line 102: „The main disadvantage of these processes..” – which processes? Corrected

 

9. please reword page 2, line 107-109 Corrected

 

10. page 2, line 123-124: “[6-9][Characterization and In Vivo Biological Performance of Biosilicate RENNO]” – please correct Corrected

 

11. please check page 3 lines 165 and 167: “185 ºC.” Corrected

 

12. page 3, line 193-194: “The samples were heated from room temperature at 750 °C, a heating rate of 20 °C/min under N2 atmosphere in a TA Instruments equipment, model TGA Q50” – The samples were heated from room temperature to 750 at a heating rate of 20 under nitrogen atmosphere in a TGAQ50 (TA Instruments).”What kind of crucibles was used? Corrected. We used Platinum crucibles

 

13. page 3, line 201: “crystalline PLA [1] apparent degree” – “crystalline PLA [1]. The apparent degree..” Corrected

 

14. page 4, line 248: “crystalline PLA [1] apparent degree” – you can omit this information, while the Bioglass doesn’t melt in this temperature range. Please be careful with the parameters assignments, such as ΔHm° in the text and the equation. Corrected the parameter. Although the Biosilicate® does not melting during the tests, the weight fraction of the PLA in the composites needs to be corrected due to the amount of the Biosilicate® added. For this case, the differences are small, however for higher contents, the changes might be expressive. The authors just wanted to provide the most suitable equation.

 

15. page 4 line 256 and other: please check the unit for torque, which is Nm, N·m, not N.m. Corrected to N m

 

16. page 4 line 266-269: “The literature shows that the main reaction of the thermo-oxidative degradation mechanism of PLA (neat) is non-radical with intramolecular transesterification. The reactions involved during the thermal degradation of PLA are non-radical, backbiting ester interchange, cis-elimination and they are dependent of the hydroxyl groups at end of PLA chain” – what is non-radical? Non-radical scission? It should be precisely written. The reactions are dependent on the presence of OH groups, that influence on .. Corrected. It is non-radical scission

17. page 4, line 272:’ “These reactions occurs..” – occur  Corrected

 

18. page 4, line 275: “in Figure 2 that presents both PLA after been processed in internal mixer” - in Figure 2 that presents the visual appearance of both PLA after processing in internal mixer Corrected

 

19. page 5 line 328: “test was performed in the Biosilicate® [17] and the result is show in” - test was performed for the Biosilicate® [17] and the result is showed in.. Corrected

 

20. page 6 line 360: “Fan et al. [18,19] prepared PLA calcium ion end capped (PLA-Ca)” – please correct are they PLA-Ca composites? No, they are no composites. According the reference the Calcium ions were inserted in the polymer chains. “The calcium ion end capped sample (PLLA-Ca) was prepared by treating the polymer/THF solution (2 g in 200 ml) with CaH2 (0.2 g, 4.76 mmol) at room temperature for 1 h. After filtrating off the unreacted CaH2, the PLLA-Ca was precipitated in methanol, and dried in vaccum.”

 

21. page 7 line 384-386: “although the Biosilicate® reduced the viscosity of both PLAs remarkably. The viscosity variation presented by both composites was equivalent when compared to the pure polymers.” – maybe better: “The presence of Biosilicate® reduced the viscosity of both PLAs remarkably, although the viscosity variation presented by both composites remained equivalent when compared to the pure polymers” Thank you for your contribution. We rewrote the sentence

 

22. page 7 line 388: “(0,01)” – please correct 0.01 Corrected

23. page 8 line 407-408: “Table 1 presents Mn and Mw of the same materials.” – please correct and leave just (Table 1) Corrected

 

24. page 8 line 414” “when compared to their pellets..” – to its pellets Corrected

 

25. page 8 line 415-416: “In order to investigate the different behavior presented for the PLAs their residual acid content (RAC) were determined.” – “In order to investigate the different behavior of the PLAs their residual acid content (RAC) values were determined” Thank you for your contribution. We rewrote the sentence

 

 

26. page 9 line 494: “The influence of PLA degradation was analyzed through thermal stability using TGA and DSC” - “The influence of PLA degradation was analyzed through thermal stability using TGA, while their thermal behavior before decomposition was registered in DSC” Thank you for your contribution. We rewrote the sentence

 

27. page 9 line 505: “that during the temperature of analysis are not decomposed.”- “that under TGA test conditions are not decomposed.” Thank you for your contribution. We rewrote the sentence

 

The next sentence should be reword or explained, what kind of reactions? Now it is opposite to the statement about solid residue in TGA. Why the amount of solid residue is higher than bioglass addition? It should be commented. Better to present TGA and DTG curves comparison than single curves, so please correct and show just two figures with PLA 2003D and 4043D materials, respectively. Please correct the axis units (TGA and DTG). The authors changed the TGA Figures and provide a possible explanation for the increase in the residue

28. Please reword the DSC discussion page 10 line 561-562 “The curve of the second heating of all samples shows that PLA was kept almost constant, approximately 60 ° C”,  line 560-575, especially line 571-573 “PLA when crystallized in the temperature range from 100 to 120 ºC can be formed crystals  α and α’ at the same time [23]. PLA 4043D and its composite was observed one shoulder at the peak fusion of PLA.” , line 575 ‘which is subsequently fused to higher”, line 592 “mass and the presence of Bioglass”, 593 “during crystallization in the composite cooling”, Thank you for your contribution. We rewrote the sentences

 

29. There is a change in the crystallinity degree for the composites, please add the proper comments to those already existing (page 11 line 592-599), Line 605: “Curves are displaced vertically for clarity” – curves were translated and presented vertically for clarity. Please correct also the Conclusions page 11 line 615-616. Thank you for your contribution. We rewrote the sentences

 

30. Please check: page 12 lines 668, 670, ref 7 and 9 “Biosilicate ®®”, line 709 ref 21 “Polym. Degrad. Stab. ! 1996”, line 693/694 ref 14 and 15, line 716 ref 25

Corrected.

Reviewer 3 Report

Thank you for considering my comments. After so many changes, authors have to check the spelling again because there are minor mistakes (no gaps, etc.). Please remember that the overall IUPAC rule is that symbols representing physical quantities (or variables) are in italic. And authors should remember in the relevant cases about the subscript (such as Tm2 should be T_m2).

Author Response

Response to Reviewer 3

 

Thank you for considering my comments. After so many changes, authors have to check the spelling again because there are minor mistakes (no gaps, etc.). Please remember that the overall IUPAC rule is that symbols representing physical quantities (or variables) are in italic. And authors should remember in the relevant cases about the subscript (such as Tm2 should be Tm2).

R: We are so grateful for valuable comments about our study. All your contributions are been accepted.

Reviewer 4 Report

Thank you for the changes made. The hard work is admired. Just a few points to be noted:

The English language could still be improved in few places such as bacterias, there is no s.

Referring to line 168, paragraph mentioning the zeta potential characterisation; One line could be added to let the readers know what sort of results are expected and how will they be used to help characterise the material. IN the materials and methods section, even though it is good to point out just what is being done, it just help the reader understand better what to expect in the results section and how this is going to help.

Also, the results and discussion section is still missing a brief introduction. The section goes direction to Figure 1. It just improves the flow in the paper if the results to be discussed was introduced first. It could just involve a rephrasing of the first line. For example, 'The 'specific methods/test/experiment'  resulted in 'such and such data' which aided in the characterisation/understanding of the degradation process and this was shown in Figure 1....

This is just an example. Any other way of introducing the results better is acceptable. 

Else, good job and keep it up.

Author Response

R: We are so grateful for valuable comments about our study. All you contributions are been accepted.

 

Thank you for the changes made. The hard work is admired. Just a few points to be noted:

 

The English language could still be improved in few places such as bacterias, there is no s. Corrected

 

Referring to line 168, paragraph mentioning the zeta potential characterisation; One line could be added to let the readers know what sort of results are expected and how will they be used to help characterise the material. IN the materials and methods section, even though it is good to point out just what is being done, it just help the reader understand better what to expect in the results section and how this is going to help.

2 Sentences were added. 1 in the results section and another in the materials and methods.

Also, the results and discussion section is still missing a brief introduction. The section goes direction to Figure 1. It just improves the flow in the paper if the results to be discussed was introduced first. It could just involve a rephrasing of the first line. For example, 'The 'specific methods/test/experiment'  resulted in 'such and such data' which aided in the characterisation/understanding of the degradation process and this was shown in Figure 1....

 

This is just an example. Any other way of introducing the results better is acceptable.

 

Else, good job and keep it up.

 

Thank you for the kind comments. A brief introduction was added.