Introducing a Novel Application of Bio-Based Fillers Based on Rice Bran Wax Infused with Green Tea: Transitioning from a Cosmetic Additive to a Multifunctional Pigment for Wood Paints

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors, 

The present work is very well structured overall, and I congratulate you for your efforts in developing the practical work and drafting the manuscript. However, certain modifications will be necessary to perfect and enhance the manuscript: 

- The introduction could benefit from a clearer statement of the originality of your research work.

- Some errors are presented in the joined report, would be better to take them into consideration.

- A high rate of self-citation is observed in your manuscript and should be reduced to reach accepted standards. 

- A plagiarism rate of over 30% is found in your introduction and should be remedied.

 

Comments for author File: Comments.pdf

Author Response

The present work is very well structured overall, and I congratulate you for your efforts in developing the practical work and drafting the manuscript. However, certain modifications will be necessary to perfect and enhance the manuscript:

 

- The introduction could benefit from a clearer statement of the originality of your research work.

Authors: the Conclusions ended with the following sentence, which described the novelty of the work: “Ultimately, the objective of the study is to underscore the potential applicability of green additives, originally intended for other applications, as viable bio-based rein-forcing and coloring materials, aligning with the environmentally conscious principles of the wood paint sector.” However, the authors also added at the end of the Conclusions: “. This study shows that rice wax is not merely an industrial byproduct but a versatile additive with the potential to enhance the protective qualities of organic wood coatings. Furthermore, incorporating green tea into the wax adds aesthetic appeal, transforming it into an effective high-performance pigment.”

 

- Some errors are presented in the joined report, would be better to take them into consideration.

Authors: The authors are uncertain whether the reviewer's comments pertain to the error bars in the graphs or to technical errors (as indicated by the reviewer). Nevertheless, the authors have included various statements in the text regarding the minimal standard deviations across the graphs, illustrating the repeatability and consistency of the obtained results.

 

- A high rate of self-citation is observed in your manuscript and should be reduced to reach accepted standards.

Authors: The authors acknowledge the reviewer's comment. However, the self-citations included are pertinent to the study, showcasing recent and relevant findings in the realm of green paints for wood. Additionally, some references were utilized to provide quantitative and qualitative comparisons with the performance of other green additives, underscoring the efficacy of the wax-based filler. In response to the reviewer's suggestion, two of the least relevant self-citations have been removed.

 

- A plagiarism rate of over 30% is found in your introduction and should be remedied.

Authors: the Introduction section has been partially rephrased, to reduce potential plagiarism.

 

Line 8: the word ‘’Viability ‘’should be replaced by another synonym, because it’s usually used to express the ability of something to live up, growth, develop under a such conditions…

Authors: the word has been changed with ‘functionality’.

 

Line 48: This part should be reworded for more comprehensive meaning ‘’ Finally, perhaps the aspect that is garnering the most attention from experts in the wood coatings sector is the utilization of alternative and eco-friendly resources as pigments and dyes ‘’  

Authors: the sentence has been changed in: “Another growing focus is the use of alternative and eco-friendly pigments and dyes. The wood paint industry is increasingly creating coatings with vibrant colors [29] for unique and appealing aesthetics [30, 31].”

 

Line 52: the expression ‘’ In pursuit of this ‘’ does not reflect the expected meaning, better to replace it.

Authors: the sentence has been changed as: “For example, the coloring potential of natural pigments from sources like spirulina [32, 33], turmeric [34], and wood waste [35] is being explored, along with microbial pigments [36, 37] that offer greater functionality and sustainability compared to traditional methods.”

 

Line 60: It is better to replace the word ‘’comprises’’ by the word ‘’consists of’’.

Authors: the sentence has been changes as requested.

 

Line 75: Better to use comma in these statements and change from ‘’Due to its distinct color and antimicrobial and antioxidant activity’’ to ‘’ Due to its distinct color, antimicrobial and antioxidant activity’’.

Authors: the sentence has been changes as requested.

 

Line 101: It is better to say ‘’ a melting point ranging from 82 to 86 °C.

Authors: the sentence has been changes as requested.

 

Line 108: It is better to say ‘’ with a moisture content varying from 6% to 9%’’.

Authors: the sentence has been changes as requested.

 

Line 117: It is better to explain the meaning of this sentence ‘’Ford Cup 5’’.

Authors: the viscosity value refers to the instrument used to measure it, i.e. the Ford Viscosity Cup 5 (a typical instrument in the world of paints). The sentence has been changed as: “…a viscosity of 50 to 60 s referring to Ford Viscosity Cup 5.”

 

Line 132: it is better to reword this sentence as follows: ‘’ The amount of UV absorber was determined based on preliminary tests performed in pervious literature studies [56].

Authors: the sentence has been changes as requested.

 

Line 144: Better to remove the comma ‘’ a final, compact’’ in this part.

Authors: the sentence has been changes as requested.

 

Line 159: It is better to reformulate this statement as follows ‘’ Gloss measurements following the ASTM D523/14 standard [57] were performed, using an Erichsen 503 instrument from Erichsen Co.Fo.Me.Gra Instruments (Milan, Italy). 

Authors: the sentence has been changes as requested.

 

Line 216:  This experiment involved testing 5 samples per series

Authors: the sentence has been changes as requested.

 

Line 348: In this part ‘‘degradation of cellulose, hemicellulose and lignin chemical structures [71-73]’’, it is preferable to only say ‘’ degradation of cellulose, hemicellulose and lignin‘’. If you would mean something with the sentence degradation of chemical structure, please reword it or provide more details.

Authors: the sentence has been changes as requested.

 

Line 368: It would be better to rephrase the sentence ‘’with the green-yellow component of the tea extract nearly entirely lost’’.

Authors: the sentence has been changed as: “…with the majority of the green-yellow component from the tea extract almost completely faded.”

 

Line 442: It is better to use another synonym of the word developed in order to avoid repetition.

Authors: the word ahs been changed in ‘observed’.

 

Line 482: The word instead in this sentence does not mention the contradiction of the second fact (It should be reworded for better meaning clarification).

Authors: the word has been removed.

 

Line 493: ‘’ This is likely due to the susceptibility 493 of tea extract to discoloration when in prolonged contact (96 h) with both aqueous and’’ It is better to reword.

Authors: the sentence has been changed as: “This is probably because tea extract is prone to discoloration when exposed for an extended period (96 h) to both aqueous and non-aqueous solutions…”.

 

Line 522: It is better to change the word ’’discount’’ by ‘’underestimate’’.

Authors: the word has been changed, as requested.

 

Line 544: it’s better to remove the comma at the end of the formula.

Authors: the comma ahs been removed

Line 545-547: This paragraph is to adjust ‘’Justify’’ .

Authors: the paragraph as been adjusted as requested.

 

Reviewer 2 Report

Comments and Suggestions for Authors

Overall, the study is well written and presented.

Please find below some of my comments regarding your manuscript:

1. Why was poplar used as the substrate for this study?

2. Line 153: Please provide the SEM parameters used for scanning.

3. Lines 196–199: It was mentioned that the cold liquid test was performed using a cold liquid test. In the case of pH 1 and 14, it is impossible to use filter paper since this high concentration will degrade the paper. Please comment on how this test with HCL and NaOH was carried out.

4. Lines 288–291: The surface roughness should have been normalised by first measuring the roughness of the substrate before and after the coating. This will have a better impact on the different batches of coatings. Indeed, a control substrate was measured, but various factors may impact the actual roughness of the coated substrate. Hence, the statement "bio-based additives do not impact the surface morphology of the composite layer is a bit vague. Please comment.

5. In the figures, consider using more defining markers and patterns in histograms for easier reading, especially in b & w. 

6. Figure 5: Why was there a slight increase in gloss at the inception (6 h) of exposure. Besides, the result shows that for all the pigmented samples and Poplar control, there was an increase in gloss compared to the initial gloss. Please comment.

7. Lines 512–513: This comment follows the previous comment (point 3), the term solely is misleading since the CA of the coated substrates is not examined. Furthermore, please include statistical significance, especially for pigmented samples.

Conclusion. What is the future plan for the study? And considering the outcome of the study, please provide a clear conclusion about the recommended concentration of pigment and if there is a need for UV additives. Perhaps it is necessary to optimize in this regard.

Author Response

Reviewer 2

 

Overall, the study is well written and presented.

Please find below some of my comments regarding your manuscript:

 

1. Why was poplar used as the substrate for this study?

Authors: the authors had already answered this question with the following sentences on line 208: “Poplar plywood, selected as the substrate for paint application, is well-known for its superior quality compared to other panel materials [54]. Its remarkably smooth surface makes it ideal for painting, laminating, or veneering [55]. Additionally, its exceptional ease of machining, especially its reputation for effortless cutting, sanding, or screwing, makes it the preferred choice for creating various samples intended for a wide range of characterization tests.

 

2. Line 153: Please provide the SEM parameters used for scanning.

Authors: the authors added the sentence at line 259: “The analyses were conducted using an acceleration voltage of 15.0 kV and operating at a working distance (WD) of 10.0 mm.”

 

3. Lines 196–199: It was mentioned that the cold liquid test was performed using a cold liquid test. In the case of pH 1 and 14, it is impossible to use filter paper since this high concentration will degrade the paper. Please comment on how this test with HCL and NaOH was carried out.

Authors: the authors partially disagree with the reviewer's assertion. The test procedure remained consistent across all liquids tested, including those with pH levels of 1 and 14. The purpose of the filter paper was to contain the solution, preventing it from dispersing or evaporating during the test, while ensuring continuous contact with the coating surface. The specific filter paper used weighed 90 g/m², which prevented degradation and enabled the test to proceed smoothly even with aggressive solutions. The weight of the filter paper was specified on line 389, to allow the reader to reproduce the test.

4. Lines 288–291: The surface roughness should have been normalised by first measuring the roughness of the substrate before and after the coating. This will have a better impact on the different batches of coatings. Indeed, a control substrate was measured, but various factors may impact the actual roughness of the coated substrate. Hence, the statement "bio-based additives do not impact the surface morphology of the composite layer is a bit vague. Please comment.

Authors: This work aims to highlight the role of different quantities of the specific bio-based filler. Specifically, all the samples were made using the same wooden substrate, which is therefore considered to have the same roughness (considering the high number of samples produced). Therefore, the impact of the filler should be assessed relative to the "clean" coating, specifically the G0 sample. Since the roughness of the different coatings is nearly identical, it is concluded that the filler does not affect this characteristic of the layer. Regardless of the initial roughness of the wooden substrate, samples G0, G5, G10, and G10U exhibit consistent roughness values. Moreover, it is important to note that the roughness measurements in both parallel and perpendicular directions to the substrate fibers are comparable across the various samples. This underscores that the substrate itself significantly influences the final roughness of the coatings. However, since this influence remains consistent across all four series of samples, the contribution of the filler becomes negligible in modifying the roughness.

5. In the figures, consider using more defining markers and patterns in histograms for easier reading, especially in b & w. 

Authors: the authors appreciate the valuable feedback from the reviewer. The markers in the figures have already been enlarged to ensure clarity. Line-dot graphs utilize distinct symbols for each sample series, ensuring differentiation even in black and white. Additionally, the histogram graphs have been updated to include different textures for each series of samples, enhancing visibility and distinction.

 

6. Figure 5: Why was there a slight increase in gloss at the inception (6 h) of exposure. Besides, the result shows that for all the pigmented samples and Poplar control, there was an increase in gloss compared to the initial gloss. Please comment.

Authors: The reviewer's observation is indeed intriguing. However, based on the authors' expertise, it is not appropriate to characterize this as a significant increase in gloss in the current study. While the graph does show a slight rise in gloss within the first 6 hours for some samples, the magnitude of this increase is minimal when considering the precision of the instrument and the standard deviation values. Apart from sample G0, the trend observed in the other samples appears to be fairly linear. In gloss measurements, substantial changes in reflectance are typically only noteworthy in clear-cut cases, such as with the G0 sample.

 

7. Lines 512–513: This comment follows the previous comment (point 3), the term solely is misleading since the CA of the coated substrates is not examined. Furthermore, please include statistical significance, especially for pigmented samples.

Authors: similarly to the previous comment, this study aims to illustrate how the filler affects the properties of the coating. Contact angles are indeed influenced by the layer's roughness, which in turn is influenced by the wooden substrate's roughness. However, by comparing the behavior of the three series of composite coatings with that of the G0 reference sample, the role of the bio-based filler can be highlighted. In this context, the filler manages to marginally enhance the hydrophobicity values of the coating. Nevertheless, as noted in line 836, the absolute contact angle values are so low that it would be inaccurate to describe the composite coatings as exhibiting true hydrophobic behavior.

 

Conclusion. What is the future plan for the study? And considering the outcome of the study, please provide a clear conclusion about the recommended concentration of pigment and if there is a need for UV additives. Perhaps it is necessary to optimize in this regard.

Authors: the authors thank the reviewer for the useful advice. The Conclusions were implemented with the following text: Therefore, this study paves the way for further research into the impact of other types of wax-based fillers in paints, leveraging the intriguing functionalities highlighted by rice bran wax. The infusion with green tea offers the ability to adjust the final color of the coating based on the amount of filler added. However, the findings indicate that 5 wt.% of additive suffices to achieve desired coloring and effective protective proper-ties. Future studies will undoubtedly be required to develop effective solutions for lim-iting the degradation of the bio-based pigment when exposed outdoors. Nonetheless, the application of UV absorbers in this study has yielded promising insights.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has been improved, I suggest it's further publication.