Morphological and Mechanical Properties of Book Cellulose-Based Paper (XXth Century) Treated with Hydroxyapatite Nanoparticles
, Ramona Marina Grigorescu 2, Lorena Iancu 2, Madalina Elena David 2, Adriana Cirstoiu 3, Georgiana Iulia Paraschiv 1 and Maria Geba 4
Moira Ambrosi
Round 1
Reviewer 1 Report
The comments are attached in a word file.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer,
Please find below our answers to your valuable comments.
Comments
Summary: The authors present the use of hydroxyapatite nanoparticles to enhance the mechanical properties of 20th paper. The experiments carried out are appropriated, but the results could be improved with just a few more.
Answer: Thanks a lot for your appreciation.
Extensive revision of English language and redaction of the manuscript are required.
Answer: Done
General concept comments: The English should be checked throughout the entire manuscript, especially some sentences where the same word is used multiple times.
Answer: Done
There is a lack of recent references, the newest is from 2016. The authors should upgrade their work with newer papers to improve the manuscript.
Answer: Done. We added more recently publications.
The conclusion section is more a summary of the results than a real conclusion of the work and should be improved.
Answer: Done
There is no analysis of the nanoparticles, so I recommend doing SEM or TEM, and including these images of the nanoparticles as well as an analysis of their size distribution in the manuscript.
Answer: The nanoparticles have been discussed and analyzed in our previous paper. But, to be more convincingly, we added new data of SEM, both for nanoparticles, and for the treated paper samples.
Specific comments: For easier tracking of the comments, the text has been highlighted in different colours: • Scientific-technical aspects: yellow • References: blue • Figures: green • Minor points: no-highlighted
Answer: Thank you. Is more helpful to see the differences and to correct or replace some paragraphs.
- The authors barely mention the effect of the microorganisms on paper degradation (biodeterioration). I suggest adding some information about the biodegradation problem, specially caused by cellulolytic fungi. Here are some useful references: • D. Allsopp, K. J. Seal, C. C. Gaylarde, Introduction to Biodeterioration., 2010, pp. 13–14. • Sterflinger, K. Fungi: their role in deterioration of cultural heritage. Fungal biology reviews. 2010, 24(1-2), 47-55. • Franco-Castillo, I., Hierro, L., Jesús, M., Seral-Ascaso, A., & Mitchell, S. G. Perspectives for antimicrobial nanomaterials in cultural heritage conservation. Chem, 2021, 7(3), 629- 669.
Answer: The aim of this paper was not to investigate the microbiological properties, which have been presented in our previous papers [4].
- Lines 74-75: “One of them is accelerated photoaging [8-12]. The influence of accelerated photoaging was also evaluated and discussed in this study.” I suggest changing these two sentences to: “One of them is accelerated photoaging [8-12], which was also evaluated and discussed in this study.”
Answer: Done
- Lines 113-115: “One of them is the use of alkaline earth metal hydroxide nanoparticles such as magnesium hydroxide (Mg(OH)2), Ca(OH)2 which can inhibit or retard cellulose degradation [20, 21].” MgO nanoparticles have been also used to preserve heritage paper due to their alkalinity and to their anti-cellulase activity, inhibiting the cellulases of two cellulolytic fungi and avoiding the degradation of the paper. I suggest adding the following reference: • Franco-Castillo, I., Guillén, E. G., Jesús, M., Silva, F., & Mitchell, S. G. (2019). Preventing fungal growth on heritage paper with antifungal and cellulase inhibiting magnesium oxide nanoparticles. Journal of Materials Chemistry B, 7(41), 6412-6419.
Answer: Done
- Lines 134-135: “The book paper sheets were first cleaned with a soft brush tool to condition them, and that the mechanical tests, thus preparing the following samples:” I suggest changing this sentence to: “The book paper sheets were first cleaned with a soft brush tool to condition them. The following samples were prepared to perform the mechanical and accelerated aging tests:”
Answer: Done
- Lines 144-148: remove these lines, as the paper samples are already described before.
Answer: Done
- Lines 149-150: “All these samples were subjected to physical-mechanical tests, for the book paper from 1938, which is more damaged than the other sample.” What “other sample” are you referring to?
Answer: The sentence was modified.
- Line 156: “Its nanoparticle dispersions…” Change “Its” to “The”.
Answer: Done
- Line 165: Add the word paper to make it clearer: “Before pH measurements, 120 mg of the paper samples were…”
Answer: Done
- Line 168: The value of the resistivity is expressed as MΩ • cm-1 , but other values are expressed as a fraction (x/y). I recommend choosing one form and using it throughout the manuscript. As a suggestion, I would rather use the x·y -1 form, as it is the one recommended by the “International System of Units”.
Answer: Modified
- Line 175: The reference 17 does not correspond to that sentence. Please revise it and add the suitable reference.
Answer: Reference revised
- Lines 189-190: The b*f and b*i definitions are the other way around.
Answer: Modified
- The lines 225-226 and 232-233 explain the same concept. Choose one and delete the other one to avoid repetition.
Answer: Lines 232-233 were deleted.
- Line 235-238: “Elastic modulus is the modulus of elasticity of paper which is less than the modulus of elasticity the fibers due to the porosity of the paper (pores do not support the load) and the random orientation of the fibers in the paper (all the fibers do not support the full load).” Rewrite this sentence, it is not well understood.
Answer: Done
- Line 253: I suggest changing “SEM investigations” to “SEM analysis”.
Answer: Done
- Line 258: change “small” with “smaller”.
Answer: Done (modified with bigger)
- Line 258: How many fibres were measured?
Answer: We measured the expected representative ones.
- Lines 264-266: “By analyzing the images is possible to observe the deposition of HAp nanoparticles on the paper fibers, because this paper type could be more easily washed than the paper from 1938.” What “paper type” do you refer? In the Materials section only the paper from the 1938 book is described.
Answer: Rephrased.
- Please check all the figures captions, some of them lack the dot after the number and the figure and the final dot.
Answer: The figures were renumbered, and the captions modified.
- Figure 3: The SEM images seem to be cropped; it seems to me that you didn’t allow the program to fully capture the image.
Answer: We changed the images, accordingly.
- Figure 3 (b): I recommend doing EDX to confirm the presence of the particles on the paper.
Answer: Done
- Figures 3 and 4: The (c) of the Figure 3 and Figure 4 has been replaced for the © symbol.
Answer: Done
- Figure 3 (c) and (d): For an untrained eye the two images look very similar. Explain more these results to highlight the presence and homogeneity of the coating.
Answer: Completed
- Line 280: I suggest changing “AFM investigations” to “AFM analysis”.
Answer: Done
- Figure 4: The text in Figure 4 is too small and difficult to read. Please increase the size font of the axis, the legend, and the titles of each image.
Answer: Done
- Lines 326-328: “Paper samples are presented and compared: original paper, original treated paper, original washed paper, original washed and treated paper, outdated original paper, and original outdated HAp-treated paper.” This is the first time the “outdated paper” is mentioned. Is it the one described as “original aging” and “treated aging” in he Figures 5-10? If so, please explain it or change the name to avoid confusion.
Answer: Changed accordingly, in order to avoid confusion.
- Lines 328-330: “It was observed that the samples treated and washed and treated with nanoparticles, have the highest pH, which is so necessary for preservation.” I suggest moving the sentence after the line 341, as I think after the explanation of the Figure 5 suits better.
Answer: Done
- Lines 330-334: “It should also be noted that the paper treated with hydroxyapatite and aged has a pH comparable to the original paper, which means that the procedures are efficient. The pH data of the cold aqueous extraction are generally more homogeneous than those measured at the surface, reflecting the overall pH of the analyzed part. The values did not fluctuate too much and varied between 4.22 and 4.80 for the tested works.” This paragraph is duplicated in lines 353-358, please delete it.
Answer: Deleted
- Lines 354-356: “Also, on the graph is represented a second axis, representing the basic weight for each type of works studied.” Please discuss the differences in weight. Why does the “original treated” weight more than the other papers?
Answer: We deleted this paragraph, considering that is a little bit confusing.
- Figures 5, 6, 7, 8 and 9:
- It is a bit difficult to deduce which axis correspond to each measurement (weight in all of them and the specific measurement of each graph).
Answer: Done
Please add a legend or indicate it with colour to make it easier for the reader.
Answer: Done
Besides, is it necessary to indicate the paper weight in all the figures? What does this value apport?
Answer: It is indicated in the Experimental Part
- The units of the “basis weight” are misspelled. Please change the “basis weight” units to g/m2 or g·m-2 , (whatever you chose from comment 8).
Answer: Done
- Please homogenize the titles of the axis in all these figures, as each one has a different size font and some of them are even in different orientations.
Answer: Done
- I recommend changing “original aging” and “treated aging” to “original aged” and “treated aged”, respectively.
Answer: Done
- Please, add the error bars to all the graphs, and you should evaluate the statistical significance between: o Original and; treated, washed, washed and treated. o Original aged and treated aged.
Answer: The figures were modified. Error bars were added.
- Lines 370-375: Are these two definitions necessary? I think you just can write: “The definition of tensile strength applied to paper is the paper length, expressed in meters, that will support its own weight and overcomes its tearing.”
Answer: Done
- Lines 380-385: “Tensile tests were carried out on 15 mm wide strips between jaws at a distance of 100 mm using a universal testing machine, equipped with a tensile cell of 500 N at a strain rate of 5 mm/min. The formula for the breaking length corresponds to eq.3: Breaking Length (m) = Tensile strength (mm) X 6, 67 X 10,000 / Grammage (g) (3)” Move this to section 2.2. Methods.
Answer: Done
- Lines 405-413: Please, discuss these results more. The “aged” papers are not even mentioned in the text.
Answer: Done
- Figure 8: Remove the italics from the age.
Answer: Done
- Lines 448-450: “Percentage elongation is the elongation at breaking, expressed as a percentage = ((final length - initial length) / initial length) x 100. % elongation = Δl / l0 x 100 [%] (4)” Move this to section 2.2. Methods and correct the “initial length” in the formula (L0).
Answer: Deleted because it is repeated
- Lines 467-470: “Regarding the criteria of yellowing of the paper, the following classes are given: Stable, with less than 3 points of the absolute b * value; Moderately stable, with b * absolutely greater than 3 and less than 8 points; Unstable, with a value greater than 8 points of the absolute value b *.” Remove the space between b and *. Where did you obtain those ranges? Please add some references to support this statement.
Answer: The space was removed. Reference was added. ASTM D6789 – 02: Standard Test Method for Accelerated Light Aging of Printing and Writing Paper by Xenon-Arc Exposure Apparatus. 2007.
- Figure 10: • What does each colour (blue and orange) represent? • Does the legend (b* Treated and b* Untreated) refer to the 48h accelerated photoaging? If so, please change the legend to: “b* control” and “b* accelerated photoaging”. • There are two “Treated” columns on the graph, why?
Answer: The figure was modified.
- Line 480: Change the number to “4. Conclusions”.
Answer: Done
- Lines 482-484: This paragraph is not a conclusion. Please rewrite it.
Answer: Rephrased
- Line 500-575: References. Please revise all the references, there are errors in some of them.
Answer: The references section was verified.
- The papers century is expressed both by arabic and roman numbers. In the title and the abstract is expressed as XXth and in the main text as 20th, I recommend choosing one and using it throughout the manuscript.
Answer: Done
Kind regards
Prof.R.Ion
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper is interesting and represents an important contribution to the study of the degradation and consolidation of paper. Unfortunately, the poor English and the many grammar errors, the confusing sentences, as well as the use of terms that are inappropriate to the context, make the article difficult to understand. For example, I think that the term "file" or "outdated" should be replaced by the more appropriate "sheet" and "aged". Furthermore, the analyzed samples should always be called by the same name to avoid further confusion. The discussion of some results is somewhat confusing, such as the discussion of the SEM results for which little is understood about the diameter of the fibers and their comparison. The most interesting part of the article is, in my opinion, that relating to the study of the mechanical properties which well indicate the consolidation achieved by treatment with hydroxyapatite NP.
Author Response
Dear Reviewer,
Please find below our answers to your valuable comments.
Thank you very much for your interest.
Comment:
The paper is interesting and represents an important contribution to the study of the degradation and consolidation of paper.
Answer: Thank you for the appreciation.
Unfortunately, the poor English and the many grammar errors, the confusing sentences, as well as the use of terms that are inappropriate to the context, make the article difficult to understand. For example, I think that the term "file" or "outdated" should be replaced by the more appropriate "sheet" and "aged".
Answer: I reconsidered and corrected the entire text.
Furthermore, the analyzed samples should always be called by the same name to avoid further confusion.
Answer: Done
The discussion of some results is somewhat confusing, such as the discussion of the SEM results for which little is understood about the diameter of the fibers and their comparison.
Answer: I completed with additional text the discussion part of the SEM results.
The most interesting part of the article is, in my opinion, that relating to the study of the mechanical properties which well indicate the consolidation achieved by treatment with hydroxyapatite NP.
Answer: Thank you for your comment.
Kind regards
Prof.Rodica Ion
Author Response File: Author Response.docx
Reviewer 3 Report
General remarks The manuscript „Morphological and mechanical properties of book cellulose-based-paper (xxth- century) treated with hydroxyapatite nanoparticles“ covers important topics with regard to the deacidification of paper. In general, the topic is of high interest, however, some corrections – in my opinion major revison - (in this in terms also of linguistic correctness, although I am not an expert in this field) are necessary before publication as outlined below. In the text, the authors repeat the same sentences several times in different places - this is unacceptable. The description of research methods is in some cases not precise and requires correction. There is even a lack of basic statistical data on the strength tests (f.ex. rule of two std dev., comparison of means, significant difference). The lack of statistics does not allow the reliability of the results to be assessed. The discussion of the optical properties (yellowing) is very brief, to brief in my opinion.
The other remarks:
Line 25 -26 - the English should be revised by a native speaker.
Line 43 - ...paper may contain hemicelluloses, lignin and additives..
Line 55 - paper exhibits reduced to aging...(what reduced?)
Line 57 - inaccurate information, - lignin is present in the papers made f.ex. of SGW, starting from 1844, and rather not common because many paper mills still produced paper from rags, also from cotton, with a very high proportion of pure cellulose in the fibers. Line 77 - There are many specyfic tests...the sentence contains trivial information, it is not known what the sentence is written for. Line 87-88 - ...that will ionic or cova,lent bond.. the English should be revised by a native speaker Line 97 - The method of... you have to guess what the authors meant in this sentence - the English should be revised by a native speaker. Line 107-109 - repetition of the content of the sentence from line 77. Lines 119 - 123 - the English should be revised by a native speaker. Line 133 - it would be useful to give the concentration of the deacidifying compound. Line 136 - 140 - "File"...rather paper sample (?),\.the English should be revised by a native speaker. Line 149 - All these samples were subjected to physical-mechanical tests, for the book paper from1938, which is more damaged than the other sample - This sentence is hard to understand. the English should be revised by a native speaker Line 156 - which was the ratio alcohol : water ? Line 258 - 259 - as above. This sentence is hard to understand. the English should be revised by a native speaker. Besides, the Fig. 3 a and 3 b show something different than what the authors claim - the diameter of the fibers in photo 3 a (before processing) is greater than in photo 3 b (after processing) Line 259 - The fibers become clearer...the photo show somthing different. Line 310 - repetition of the content of the sentence from the Introduction (Line 49) Line 312 - ...presence of metal ions in the paste. What is this term - paste? Have the authors check the terminology. Lines 312 -314 - repetition of the content of the sentences from Introduction (Lines 52-53). Lines 315 - 325 - I suggest removing this fragment of the text. It does not refer directly to the experimental data, it contains trivial and not entirely accurate information (the papers from last two centuries do not necessarily contain significant amounts of lignin. Lines 326-327 - the description of the samples should be consistent with the terminology used in the experimental part Line 336 - PH - pH Line 350 -352 - repetition of the content of the sentence (Lines 328-330). Line 356-358 - repetition of the content of the sentence (Line 332-334). Line 354 - ...on the graph is represented a second axis, representing the basic weight for each type of
works studied. And the results of this is? No authors comment on these data. Line 366-368, 393-397, 407-410, 441-445, 448 - 450 - the information does not relate to the test results. If they were to be included in the work, then rather in the part describing the research methods (Methods) not the results. Line 509 – correction of the year of publication
Author Response
Dear Reviewer,
Thank you very much for your detailed comments. Please find below our answers.
General remarks
The manuscript „Morphological and mechanical properties of book cellulose-based-paper (xxth- century) treated with hydroxyapatite nanoparticles “covers important topics with regard to the deacidification of paper.
Answer: Thank you for your appreciation.
In general, the topic is of high interest, however, some corrections – in my opinion major revison - (in this in terms also of linguistic correctness, although I am not an expert in this field) are necessary before publication as outlined below.
Answer: We’ve done the English correction, hopefully more adequate.
In the text, the authors repeat the same sentences several times in different places - this is unacceptable.
Answer: We corrected the entire text and excluded the repeated text.
The description of research methods is in some cases not precise and requires correction.
Answer: Corrected.
There is even a lack of basic statistical data on the strength tests (f.ex. rule of two std dev., comparison of means, significant difference). The lack of statistics does not allow the reliability of the results to be assessed.
Answer: The statistic analysis for pH and mechanical properties was added and discussed.
The discussion of the optical properties (yellowing) is very brief, to brief in my opinion.
Answer: Completed
The other remarks:
Line 25 -26 - the English should be revised by a native speaker.
Answer: Done
Line 43 - ...paper may contain hemicelluloses, lignin and additives..
Answer: Corrected
Lines 51-53 - inaccurate information - acid digestion was common in the mid-twentieth century, then the alkaline sulphate method began to dominate, until today.
Answer: Corrected
Line 55 - paper exhibits reduced to aging...(what reduced?)
Answer: Corrected
Line 57 - inaccurate information, - lignin is present in the papers made f.ex. of SGW, starting from 1844, and rather not common because many paper mills still produced paper from rags, also from cotton, with a very high proportion of pure cellulose in the fibers.
Answer: Corrected
Line 77 - There are many specific tests...the sentence contains trivial information, it is not known what the sentence is written for.
Answer: Excluded
Line 87-88 - ...that will ionic or covalent bond.. the English should be revised by a native speaker
Answer: Corrected
Line 97 - The method of... you have to guess what the authors meant in this sentence - the English should be revised by a native speaker.
Answer: Corrected
Line 107-109 - repetition of the content of the sentence from line 77.
Answer: Deleted
Lines 119 - 123 - the English should be revised by a native speaker.
Answer: Corrected
Line 133 - it would be useful to give the concentration of the deacidifying compound.
Answer: Done
Line 136 - 140 - "File"...rather paper sample (?),\.the English should be revised by a native speaker.
Answer: Done
Line 149 - All these samples were subjected to physical-mechanical tests, for the book paper from
1938, which is more damaged than the other sample - This sentence is hard to understand. the English should be revised by a native speaker
Answer: Corrected
Line 156 - which was the ratio alcohol : water ?
Answer: 50%-50%
Line 258 - 259 - as above. This sentence is hard to understand. the English should be revised by a native speaker.
Answer: Done
Besides, the Fig. 3 a and 3 b show something different than what the authors claim - the diameter of the fibers in photo 3 a (before processing) is greater than in photo 3 b (after processing)
Answer: Corrected
Line 259 - The fibers become clearer...the photo show something different.
Answer: Corrected
Line 310 - repetition of the content of the sentence from the Introduction (Line 49)
Answer: Corrected
Line 312 - ...presence of metal ions in the paste. What is this term - paste? Have the authors check the terminology.
Answer: Corrected
Lines 312 -314 - repetition of the content of the sentences from Introduction (Lines 52-53).
Answer: Corrected
Lines 315 - 325 - I suggest removing this fragment of the text. It does not refer directly to the experimental data; it contains trivial and not entirely accurate information (the papers from last two centuries do not necessarily contain significant amounts of lignin.
Answer: Removed
Lines 326-327 - the description of the samples should be consistent with the terminology used in the experimental part
Answer: Corrected
Line 336 - PH - pH
Answer: Corrected
Line 350 -352 - repetition of the content of the sentence (Lines 328-330).
Answer: Corrected
Line 356-358 - repetition of the content of the sentence (Line 332-334).
Answer: Corrected
Line 354 - ...on the graph is represented a second axis, representing the basic weight for each type of works studied. And the results of this is? No authors comment on these data.
Answer: We kept the weight only for those parameters which depends on weight, for the others (elongation and modulus of elasticity) we removed the weight.
Line 366-368, 393-397, 407-410, 441-445, 448 - 450 - the information does not relate to the test results. If they were to be included in the work, then rather in the part describing the research methods (Methods) not the results.
Answer: Done. All these informations have been moved at Methods.
Line 509 – correction of the year of publication
Answer: All the references were verified.
Kind regards
Priof.Rodica Ion
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Comments for author File: Comments.docx
Reviewer 2 Report
Some minor revisions of language and grammar are required. Mainly check the introduction, the description of mechanical tests in the Methods section and pH tests' results and tensile strength results.
