Degradation Characteristics of Environment-Friendly Bamboo Fiber Lunch Box Buried in the Soil

Round 1

Reviewer 1 Report

Although the manuscript does not contain any outstanding new and significant information it may be considered for publication after revision.

English requires editing and revision.

Title should be changed. According to the title the authors are interested in the degradation characteristics of the soil and not of the lunch box material. Suggestion for title: Degradation characteristics of environmental-friendly bamboo fiber lunch box buried in soil.

Throughout the text replace “bamboo fiber environmental-friendly lunch box” with “environmental-friendly bamboo fiber lunch box”

L16 (Abstract) “increased rapidly-slowly-fast” is very confusing. Rewrite more clearly.

L294 rewrite, because crystallinity cannot interact with anything, crystalline regions can.

 

L338. Not once in the manuscript is there mention that the lunchbox dealt with is made of polyester. 

Author Response

Responses to the comments of reviewer 1 from forests

1. Title should be changed. According to the title the authors are interested in the degradation characteristics of the soil and not of the lunch box material. Suggestion for title: Degradation characteristics of environmental-friendly bamboo fiber lunch box buried in soil.

Response:

Thank you very much for pointing this out. We have corrected it. Title: Degradation characteristics of environment-friendly bamboo fiber lunch box buried in soil.

2. Throughout the text replace “bamboo fiber environmental-friendly lunch box” with “environmental-friendly bamboo fiber lunch box”.

Response:

Thank you very much for pointing out that. We have revised it all in the text.

3. L16 (Abstract) “increased rapidly-slowly-fast” is very confusing. Rewrite more clearly.

Response:

Thank you very much for pointing this out, and we have corrected it. This sentence has been revised to read: The curve of weight loss rate increased rapidly to slowly to quickly.

4. L294 rewrite, because crystallinity cannot interact with anything, crystalline regions can.

Response:

Thank you very much for pointing this out. This sentence has been revised to read: crystalline regions interacted with the water and microorganisms.

5. L338. Not once in the manuscript is there mention that the lunch box dealt with is made of polyester.

 Response:

Thank you very much for pointing this out. This sentence has been revised to read: It was a good substitute for a biodegradable polyester lunch box.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript of Jiang et al., investigated the (microbial) degradation of a bamboo based lunch box. Bamboo based materials and composites are widely studied in the area of composite materials, however, the approach of the authors is well performed and therefore deserves recognition in this area of research. The article is well written and the applied methodology merits publication in Forests. However, after reading the manuscript I have some major and minor comments which ought to be addressed before publication:

-        -  From which bamboo species do the fibers originate from ? Is it commercially grown bamboo ? If so, please add region, age, etc.

-         -  Is there additional information regarding the chemical composition (Van Soest) of the bamboo fibers before and after steam explosion?

-       -   A fine and rough grinding step (before the molding process) is mentioned in the text. What are the eventual fiber dimensions?

-          - The authors correctly indicate in the introduction section that in various applications additives are used to decrease hygroscopicity and increase mechanical properties. In this study no additives (besides tapioca starch) are used. The tensile (mechanical properties) of the material has been tested, however less attention is given to hygroscopicity. Dynamic Vapor Sorption (DVS) testing would shed some light on the hygroscopicity properties of this material. The hygroscopicity should be addressed to some extent in the text. The authors claim to provide an environmental friendly alternative to (toxic) composite lunch boxes, but if this new material has (potential) inferior properties compared to more traditional lunch boxes this should be clearly stated.

-         -  Figure 2 should be adjusted so that it is more clear for the reader. Some parts are too small/unclear to read/see.

-        -   Likewise for Figure 3, for example the legend in Figure 3 (j) is unreadable without too much zooming in.

-         -  Please indicate in the manuscript which tests have been conducted in triplicate/duplicate. Sometimes an error bar is shown, sometimes there is no error bar.

-        -   Regarding the Van Soest analysis, how is the sample prepares prior analysis ? Are the sheets ground into a certain particle size prior analysis or are they applied as such ? Please elaborate.

-        -  The article deals about the (microbial) degradation of a lunch box, therefore the reviewer wonders if anything is known about the microbial consortia (for example via a microbial assay) involved in this degradation mechanism.

-        -  It would be a good idea to introduce a paragraph with a discussion/critical reflection. For example: how does is this material ranked compared to other alternatives ? Is the degradation mechanism likewise ? Is faster ? Compare properties and experimental degradation with comparable alternatives.

Author Response

Responses to the comments of reviewer 2 from forests

1. From which bamboo species do the fibers originate from? Is it commercially grown bamboo? If so, please add region, age, etc.

Response:

Thank you very much for pointing this out. The environmental-friendly bamboo fiber lunch box is made from 2 to 3 years old bamboo (Bambusa pervariabilis McClure × Dendrocalamopsis daii Keng f.) grown in Chongqing Province, China.

2. Is there additional information regarding the chemical composition (Van Soest) of the bamboo fibers before and after steam explosion?

Response:

Thank you very much for pointing this out. This paper focuses on the chemical composition changes of the bamboo fiber lunch box at various stages of degradation. We didn't pay much attention to the chemical composition (Van Soest) of bamboo fibers before and after the steam explosion. Figure 6(b) shows the chemical composition (Van Soest) of the bamboo fiber lunch box (the product produced through the complete process).

3. A fine and rough grinding step (before the molding process) is mentioned in the text. What are the eventual fiber dimensions?

Response:

Thank you very much for pointing this out. Beating degree is 37°SR±2°SR. The length of the fiber after pulping is known as beating degree. The longer the pulping time, the higher the value of the beating degree, and the shorter the fiber.

4. The authors correctly indicate in the introduction section that in various applications additives are used to decrease hygroscopicity and increase mechanical properties. In this study no additives (besides tapioca starch) are used. The tensile (mechanical properties) of the material has been tested, however less attention is given to hygroscopicity. Dynamic Vapor Sorption (DVS) testing would shed some light on the hygroscopicity properties of this material. The hygroscopicity should be addressed to some extent in the text. The authors claim to provide an environmental friendly alternative to (toxic) composite lunch boxes, but if this new material has (potential) inferior properties compared to more traditional lunch boxes this should be clearly stated.

Response:

Thank you very much for pointing this out. This research focuses on the lunch box's degradation process during various stages of burial, including physical qualities, mechanical strength, chemical structure, and so on. The hygroscopicity of this material is a more basic measure of product performance. Hygroscopicity is not used as one of the measures of degradation performance in the traditional literature on degradation.

Bamboo, like wood, straw, and other biomass resources, is not harmful to the soil. The term "environmentally friendly" refers to the fact that the box contains no compounds that are known to be harmful to the soil. However, we did not include information in the text on the soil's physical and chemical qualities, as well as heavy metal elements. There are inadequate soil samples because the whole degradation process only contains data on the soil for days 0, 40, and 70.

5. Figure 2 should be adjusted so that it is more clear for the reader. Some parts are too small/unclear to read/see.

Likewise for Figure 3, for example the legend in Figure 3 (j) is unreadable without too much zooming in.

Response:

Thank you very much for pointing this out. we have corrected it all in the text. Please check it.

6. Please indicate in the manuscript which tests have been conducted in triplicate/duplicate. Sometimes an error bar is shown, sometimes there is no error bar.

Response:

Thank you very much for pointing this out. we have revised it all.

7. Regarding the Van Soest analysis, how is the sample prepares prior analysis? Are the sheets ground into a certain particle size prior analysis or are they applied as such? Please elaborate.

Response:

Thank you very much for pointing this out. The samples from each degradation date were crushed into a 60-mesh powder, dried, and prepared for use. The test was repeated twice, with the findings averaged.

8. The article deals about the (microbial) degradation of a lunch box, therefore the reviewer wonders if anything is known about the microbial consortia (for example via a microbial assay) involved in this degradation mechanism.

Response:

Thank you very much for pointing this out. Although it would have been preferred to include microbiological analyses in the text, the authors' areas of research are unrelated to microbiology (identifying, counting, sequencing microbial species, and so on), thus no relevant tests have been performed.

9. It would be a good idea to introduce a paragraph with a discussion/critical reflection. For example: how does is this material ranked compared to other alternatives? Is the degradation mechanism likewise? Is faster? Compare properties and experimental degradation with comparable alternatives.

Response:

Thank you very much for pointing this out. I couldn't agree more with you on that. Actually, I did soil degradation tests on polyester lunch boxes and wood pulp lunch boxes. The degradation data from the bamboo fiber lunch box was analyzed, and the other lunch boxes will still be tested. Based on the test data presented thus far, polyester lunch boxes degrade in about 6 months or more, while pulp lunch boxes degrade in about 3 months. The degradation mechanism of polyester lunch boxes is more concerned with molecular chain hydrolysis and assimilation by microorganisms. Because of the surface coating on pulp lunch boxes, the pulp part is removed first, and the remaining polypropylene remains in the soil for a long time, explaining why bamboo fiber lunch boxes degrade faster than pulp lunch boxes.

Author Response File: Author Response.docx

Reviewer 3 Report

Summary:

This paper investigated the effects of anabolic biodegradability of bamboo-based lunch boxes on physical, structural, and chemical properties. Bamboo-based lunch boxes are completely biodegraded after 70 days. Burial weight loss (%) results showed that biodegradation was not consistent due to starch, hemicellulose, cellulose, and lignin biodegrading at different rates due to reactions to microorganisms. The degradation characteristics include; color changes, microcracks, decrease in tensile strength, higher weight loss, disintegration, and complete degradation and integration with soil after 70 days.

Reviewer's general comment:

Although this research is promising and plant-based single-use utensils are the future, the manuscript requires deep revision due to a lack of scientific soundness and proper presentation. The introduction discussed well the environmental problem caused by the overuse of single-use plastics-based utensils. Furthermore, it reviewed the current trend in biodegradable lunch boxes. However, this did not give justifications for the present study. The aim of this study, which is different than what is written in the abstract, is to investigate the effects of anabolic biodegradability of bamboo-based lunch boxes on physical, mechanical, structural, and chemical properties over a period of time. Given the aim, scientific gaps should be brought out systematically, particularly the effect of the anabolic biodegradability of plant-based utensils on physical, mechanical, structural, and chemical properties.

There are significant errors in the methods followed, particularly in determining the chemical composition and XRD analysis. Furthermore, TGA/DTG, FTIR, and XRD figures show possible wrong measurements or lack proper presentation, thereby should be replaced. Figures must be divided and placed around their respective section. Curves, spectra, and samples must be observable to the readers. There is a lack of references supporting claims made in this manuscript and comparing results from other studies. Besides, there are many grammatical mistakes throughout the manuscript, which require professional English language editing.

The following points must be addressed:

1

·   ●Potential conflict of interest. The materials used in this research are bamboo lunch boxes produced by Chongqing Ruizhu Plant fiber. Co.. The authors must declare a conflict of interest if there is any.

  ●The aim of the manuscript is not precise. The abstract seeks to investigate the anabolic degradation behavior of indoor burial of bamboo-based lunch boxes. However, in the introduction, the study aims to examine effects of the anabolic degradation behavior of bamboo-based lunch boxes on physical, mechanical, structural, and chemical properties.

  ●The manuscript lacks scientific soundness and poor presentation, particularly in the results and discussion section.

· ●Require deep English language editing and major revision.

· ●Key information such as standards followed and experiment controls were missing.

· ●There are no citations supporting claims or explaining the results in the results and discussion. For example, citations supporting FTIR peak intensities, TGA decomposition peaks, and temperature ranges.

· ●There are no comparisons between other studies of biodegradable lunch boxes. It is important to compare obtained results between biodegradation behavior and rates of other studies.

  ●Statistical analysis to enable a more objective conclusion to be made. For example, statistically significant differences in tensile strength or burial weight loss (%).

  ● XRD results require revision. The materials are made into powders before X-ray diffraction is conducted. This will influence the outcome of the study since it will destroy crystalline regions. Therefore, crystalline indices are most likely wrong.

·  ●Figure 2(b),(d),(e) & Figure 3(h)&(i) are too small to observe changes.

· ●SEM micrographs in Figure 3(g) require labeling, emphasizing the differences, and uniform magnification.

· ●Degradation days reported for each test are different.

· ●Essential controls were missing (e.g., weights and dimensions of samples, correct magnification for SEM, reference for testing standards, chemicals used for determining chemical composition, days).

 

Here is my review point by point comments

1. Introduction

Line 43

●Please change "documents" to "policies".

Lines 66 – 78

●This should be written in the materials section.

●The references mentioned are for the stream explosion procedure.

Lines 79 – 86

·    ● The aim of this study must be the same as the abstract.

 

 

2. Materials and Methods

● Please fix sub-section names and numbers to the following:

● "2.1 Test materials → 2.1 Materials

● "2.2 Test method , "2.2.2 Test of degradation performance, and (1) Weight loss rate" → 2.2 Disintegration and Biodegradability.

● "(2) Tensile properties" → 2.3 Tensile properties

● "(3) Topography shooting" → 2.4 Scanning electron microscopy (SEM)

● "(4) Thermal performance" → 2.5 Thermogravimetric analysis/derivative thermogravimetry (TGA/DTG)

● "(5) Infrared spectrum" → 2.6 Fourier transform infrared spectroscopy (FTIR)

●"(6) Contents of cellulose, hemicellulose, and lignin" → 2.7 Chemical composition

●"(7) Relative Crystallinity" → 2.8 X-ray diffraction (XRD)

These changes will allow the easier readability of the manuscript. In addition, "2.2 Test method", "2.2.2 Test of degradation performance", and "(1) Weight loss rate", should be all under one sub-section named "2.2 Disintegration and Biodegradability". Because these sections follow the same standards; Chinese national standards GB/ T 197275- 2003.

2.1 Materials (Lines 89 – 94)

●Please cite a reference of the preparation method, if possible.

●Please include the weight of the lunch box.

● Please include particle size of bamboo fiber & tapioca starch.

●Please include supplier and additional information about tapioca starch.

●Please include more information about the hot-pressing machine (e,g. model, marker, county of marker)

●The purpose of adding tapioca starch should be clearly expressed here.

Lines 100 – 109

●Please cite a reference to GB/T 19275 -2003.

●In this section, please define major degradation dates.

Line 116

●Please cite equation in line 117 as "Eq. (1)".

Lime 117

●Please add equation number after the equation.

Lines 119 – 123

●Please add dimensions (height, thickness, width) of the testing pieces. as this could potentially influence the outcome of the study.

Line 130

●The magnification are written in range, which is not precise. The magnification must be written in this format 50, 5000x magnification.

●Could it be 500x magnification? Please check if the magnifications are correct because the difference in micrometer sizes labeled in figure.3 is 1 to 10µm. This is too small, so it must be 50 and 500x magnifications.

●Please ensure that magnification is labelled also in SEM micrographs in Figure.3. SEM conditions must be the same when comparing degradation rates.

Lines 131 – 135

·   ●Please add information about samples weights.

    ●Please add more details about the purpose of this test.

    ● Figure 2.(f) is not clear how it is supposed to determine thermal properties.

·  ●It would be better if the results are expressed in a table showing; onset temperature at x% mass loss percentages, major decomposition peak, and endset temperature mass loss percentage.

Lines 140 – 144

·    ●What are these abbreviations (NDF, ADL, ADS)?

·  ●Please add more details about the detergent used in this format, for example "acetic acid (CH3COOH, Kanto Chemical co.,INC, 99.7%)".

·  ●The method mentioned are not the standard method for determining cellulose, hemicellulose and lignin.

Lines 146 – 150

·  ●What is the purpose of conducting X-ray diffraction? The objective should be clearly mentioned in this section.

·  ●How were crystallinity indices measured? Please include an equation formula or/and cite a reference of the standard followed.

·  ●Why were the samples grounded into powder? It will destroy crystalline regions and most likely will influence crystallinity. In other words, when you ground materials, they become amorphous, thus could not indicate the biodegradation rate of the lunch box.

·  ●It would be better to report the degraded samples' degradation rate by cutting intact test pieces from degraded samples, then conducting x-ray diffraction to measure the crystalline regions.

·   ●This will report the degradation rates by decreasing crystallinity indices over time.

 

Lines 160 – 188

·    ●Require deep revision in English language. There are major mistakes. For example, "the weight loss rate increased rapidly".

·     ●It would be better if figures were placed in their corresponding section.

·     ●There is no comparison between results from other studies.

Lines 190 – 202

"The change process had mainly three stages. The first stage was from 50℃ to 200℃, which was mainly the water evaporation stage, including free water and bound water. At this time, the chemical composition was basically unchanged"

● There are no citations of any studies supporting these claims. In the literature review, water evaporation is around 50 – 130° C.

Figures

●Figures should be divided and placed into their corresponding section.

Figure 2 (a)

●The curve should be descending similarly to TGA curves in (d) because it is a mass loss (%).

Figure 2 (b), (e), (d)

● It was difficult to observe the differences between these figures.

Figure 2 (f)

● It not clear what is the authors trying to convey.

Figure 3

·    ●Why figure.3 letters started with "(g)"? It should be “Figure.3(a), (b), (c), (d).”

·  ●It would be better if SEM micrographs, biofilms, fiber expansions, fragmentation, and micro-cracks were labeled.

Lines 293 – 305

·    ●It would be better if SEM micrographs and figure 4 were placed under this section.

 

Conclusion

·  ●The authors claim that bamboo-based lunch boxes displayed excellent degradation performance and degraded the soil in 70 days. However, there is no comparison of the reported results of other biodegradable lunch boxes.

·     ● The results reported did not support the claims made in 333 – 344.  

Author Response

Responses to the comments of reviewer 3 from forests

1. Although this research is promising and plant-based single-use utensils are the future, the manuscript requires deep revision due to a lack of scientific soundness and proper presentation. The introduction discussed well the environmental problem caused by the overuse of single-use plastics-based utensils. Furthermore, it reviewed the current trend in biodegradable lunch boxes. However, this did not give justifications for the present study. The aim of this study, which is different than what is written in the abstract, is to investigate the effects of anabolic biodegradability of bamboo-based lunch boxes on physical, mechanical, structural, and chemical properties over a period of time. Given the aim, scientific gaps should be brought out systematically, particularly the effect of the anabolic biodegradability of plant-based utensils on physical, mechanical, structural, and chemical properties.

Response:

Thank you very much for pointing this out. we did not specifically identify scientific gaps between this study and the current research on plant-based utensils degradation in the introduction section. Furthermore, biodegradation mechanisms were not described from various aspects (such as physical, mechanical, structural, and chemical properties). Introduction has been rewritten. Please check the attachment file.

2. There are significant errors in the methods followed, particularly in determining the chemical composition and XRD analysis. Furthermore, TGA/DTG, FTIR, and XRD figures show possible wrong measurements or lack proper presentation, thereby should be replaced. Figures must be divided and placed around their respective section. Curves, spectra, and samples must be observable to the readers. There is a lack of references supporting claims made in this manuscript and comparing results from other studies. Besides, there are many grammatical mistakes throughout the manuscript, which require professional English language editing.

Response:

Thank you very much for pointing this out. In response to your comments, I have revised each point in the specific comments below. Please check it.

3. Potential conflict of interest. The materials used in this research are bamboo lunch boxes produced by Chongqing Ruizhu Plant fiber. Co.. The authors must declare a conflict of interest if there is any.

Response:

Thank you very much for pointing this out. The company declares no conflict of interest. we mentioned it in the conflict of interest.

4. The aim of the manuscript is not precise. The abstract seeks to investigate the anabolic degradation behavior of indoor burial of bamboo-based lunch boxes. However, in the introduction, the study aims to examine effects of the anabolic degradation behavior of bamboo-based lunch boxes on physical, mechanical, structural, and chemical properties.

Response:

Thank you very much for pointing this out. The aim of the manuscript seeks to investigate the degradation behavior of indoor burial of bamboo-based lunch boxes. According to the literature on degradation behavior, degradation behavior includes changes in microscopic morphology, physical properties, mechanical properties, and chemical components of the material throughout the degradation process. we didn't make it clear in the introduction. The introduction has been revised.

5. The manuscript lacks scientific soundness and poor presentation, particularly in the results and discussion section.

Response:

Thank you very much for pointing this out. we have cited relevant research and compared it to the degradation of other lunch boxes in the Results and Discussion section. Please check it.

6. Require deep English language editing and major revision.

Response:

Thank you very much for pointing this out. we have revised English language.

7. Key information such as standards followed and experiment controls were missing.

Response:

Thank you very much for pointing this out. I have listed the mentioned standards, formulas, and references in the Materials and Methods section.

8. There are no citations supporting claims or explaining the results in the results and discussion. For example, citations supporting FTIR peak intensities, TGA decomposition peaks, and temperature ranges.

Response:

Thank you very much for pointing this out. we have revised it. In fact, the literature on soil degradation of plant fiber lunch boxes is limited, and the majority of the literature cited in the Results and Discussion section refers to changes in fibers or fiber composites in soil and fiber decomposition by microorganisms.

9. There are no comparisons between other studies of biodegradable lunch boxes. It is important to compare obtained results between biodegradation behavior and rates of other studies.

Response:

Thank you very much for pointing this out. we have revised it. Please check the manuscript.

10. Statistical analysis to enable a more objective conclusion to be made. For example, statistically significant differences in tensile strength or burial weight loss (%).

Response:

Thank you very much for pointing this out. we totally agree with you there. In fact, with respect to the correlation between physical properties (mass percentage) and mechanical properties (tensile strength) of bamboo fiber lunch box during the degradation process, we did a data analysis. The data results showed a very significant relationship between mass percentage and tensile strength. Pearson coefficient was 0.986. This implies a significant intrinsic link between the degradation of the lunch box's physical and mechanical qualities as a result of the influence of soil on it. However, the association between the two tells us little in the literature on traditional material degradation property analysis, because there are various factors impacting soil degradation, including soil conditions and lunchbox characteristics. We cannot be certain that the correlation between mass percentage and mechanical properties of this lunch box is significant under any degradation conditions. As a result, we did not include correlation analysis in the Results and Discussion section, which makes the structure of this section unclear.

11. XRD results require revision. The materials are made into powders before X-ray diffraction is conducted. This will influence the outcome of the study since it will destroy crystalline regions. Therefore, crystalline indices are most likely wrong.

Response:

Thank you very much for pointing this out. we have responded to your specific comments below.

12. Figure 2(b), (d), (e) & Figure 3(h)&(i) are too small to observe changes.

Response:

Thank you very much for pointing this out. we have revised it all.

13. SEM micrographs in Figure 3(g) require labeling, emphasizing the differences, and uniform magnification.

Response:

Thank you very much for pointing this out. we have revised it all.

14. Degradation days reported for each test are different.

Response:

Thank you very much for pointing this out. The weight loss rate for the lunch box is calculated over a seven-day period. Tensile strength is measured during the pre-degradation stage to monitor the decrease in strength, which is impossible to measure due to the strength approaching zero and the great variability. The findings for the other degradation performance are not shown every seven days since the performance change is not visible every seven days, thus representative days were chosen to analyze the performance change.

15. Essential controls were missing (e.g., weights and dimensions of samples, correct magnification for SEM, reference for testing standards, chemicals used for determining chemical composition, days).

Response:

Thank you very much for pointing this out. we have updated the text in the Materials and Methods section.

16. Introduction

Line 43            ●Please change "documents" to "policies".

Lines 66 – 78   ●This should be written in the materials section.

                        ●The references mentioned are for the stream explosion procedure.

Lines 79 – 86   ● The aim of this study must be the same as the abstract.

Response:

Thank you very much for pointing this out.

• The word in line 43 has been corrected.
• Line 66-78 is written in the “2.1 materials”. Chemical testing of the hemicellulose and lignin accumulated on the surface of bamboo fiber lunch box after steam explosion has not been done, and the literature provided is a description of the bamboo qualities after steam explosion. The materials part has been rewritten.
• The introduction and abstract have been updated with new information.

17. Materials and Methods

• Please fix sub-section names and numbers to the following:
• "2.1 Test materials → 2.1 Materials
• "2.2 Test method, "2.2.2 Test of degradation performance, and (1) Weight loss rate" → 2.2 Disintegration and Biodegradability.
• "(2) Tensile properties" → 2.3 Tensile properties
• "(3) Topography shooting" → 2.4 Scanning electron microscopy (SEM)
• "(4) Thermal performance" → 2.5 Thermogravimetric analysis/derivative thermogravimetry (TGA/DTG)
• "(5) Infrared spectrum" → 2.6 Fourier transform infrared spectroscopy (FTIR)
• "(6) Contents of cellulose, hemicellulose, and lignin" → 2.7 Chemical composition
• "(7) Relative Crystallinity" → 2.8 X-ray diffraction (XRD)

These changes will allow the easier readability of the manuscript. In addition, "2.2 Test method", "2.2.2 Test of degradation performance", and "(1) Weight loss rate", should be all under one sub-section named "2.2 Disintegration and Biodegradability". Because these sections follow the same standards; Chinese national standards GB/ T 197275- 2003.

Response:

Thank you very much for pointing this out. we have revised it all in the manuscript.

18. Materials (Lines 89 – 94)

• Please cite a reference of the preparation method, if possible.
• Please include the weight of the lunch box.
• Please include particle size of bamboo fiber & tapioca starch.
• Please include supplier and additional information about tapioca starch.
• Please include more information about the hot-pressing machine (e.g. model, marker, county of marker)
• The purpose of adding tapioca starch should be clearly expressed here.

Response:

Thank you very much for pointing this out. Materials has been rewritten. we don't have any more additional information about the starch, including its particle size. Although the hot pressing time and temperature data are described in the text, the hot pressing machine lacks the model and manufacturer.

19. Lines 100 – 109 ●Please cite a reference to GB/T 19275 -2003.

• In this section, please define major degradation dates.

Response:

Thank you very much for pointing this out.we have cited a reference to GB/T 19275 -2003 and defined major degradation dates.

20. Line 116  ●Please cite equation in line 117 as "Eq. (1)".

Lime 117       ●Please add equation number after the equation.

Response:

Thank you very much for pointing this out. we have cited equation in line 117 as "Eq. (1)" and added equation number after the equation.

21. Lines 119 – 123  ●Please add dimensions (height, thickness, width) of the testing pieces. as this could potentially influence the outcome of the study.

Response:

Thank you very much for pointing this out. we have added dimensions of the samples.

22. Line 130 ●The magnification are written in range, which is not precise. The magnification must be written in this format 50, 5000x magnification.

• Could it be 500x magnification? Please check if the magnifications are correct because the difference in micrometer sizes labeled in figure.3 is 1 to 10µm. This is too small, so it must be 50 and 500x magnifications.
• Please ensure that magnification is labelled also in SEM micrographs in Figure.3. SEM conditions must be the same when comparing degradation rates.

Response:

Thank you very much for pointing this out. 1000x magnifications, corresponding to 10 µm. we have labelled magnification in SEM micrographs.

23. Lines 131 – 135 

     ●Please add information about samples weights.

• Please add more details about the purpose of this test.
• Figure 2. (f) is not clear how it is supposed to determine thermal properties.
• It would be better if the results are expressed in a table showing; onset temperature at x% mass loss percentages, major decomposition peak, and endset temperature mass loss percentage.

Response:

Thank you very much for pointing this out. A thermogravimetric analyzer (TA Instruments, Milford, NJ, USA) was used to determine the thermal stability and degradation of the lunch box in different degradation stages. The sample, which weighs approximately 5 mg, The thermal stability is presented in the form of a table with the results. Please check it.

25. Lines 140 – 144

     ●What are these abbreviations (NDF, ADL, ADS)?

• Please add more details about the detergent used in this format, for example "acetic acid (CH3COOH, Kanto Chemical co.,INC, 99.7%)".
• The method mentioned are not the standard method for determining cellulose, hemicellulose and lignin.

Response:

Thank you very much for pointing this out.

• The undissolved residue from boiling plant-based feeds with neutral detergent was neutral detergent fiber (NDF), primarily cell wall components such as cellulose, hemicellulose, lignin, and silicate. Acid detergent was used to treat the plant-based feed, and the waste was acid detergent fiber (ADF), which contained cellulose, lignin, and silicate. The residue of acid detergent fiber after 72 percent sulfuric acid treatment was lignin and silicate, and this residue was deducted from the acid detergent fiber value to determine the cellulose percentage of the feed. The acid detergent lignin (ADL) content of the residue after 72 percent sulfuric acid treatment was determined by ashing the fraction that escaped during ashing. Hemicellulose content was ADS (%) = NDF (%) – ADF (%).
• we have revised it.
• There are three traditional methods for determining the concentration of the three main chemical components in plant fibers [1]. (1) Comprehensive plant fibre analysis [2], (2) Agricultural fibre analysis [3], and (3) Strong acid hydrolysis [4]. Agricultural fibre analysis is a gravimetric method used for analysis of agricultural lignocelluloses [3]. The Van Soest method was used in this paper based on the laboratory conditions.

[1] Thygesen, A., Oddershede, J., Lilholt, H., Thomsen, A. B., & Ståhl, K. (2005). On the determination of crystallinity and cellulose content in plant fibres. Cellulose, 12(6), 563-576.

[2] Browning B.L. 1967. Methods of Wood Chemistry. Interscience Publishers, A division of John Wiley & Sons, New york.

[3] Goering, H. K., & Van Soest, P. J. (1970). Forage fiber analyses (apparatus, reagents, procedures, and some applications) (No. 379). US Agricultural Research Service.

[4] Kaar, W. E., Cool, L. G., Merriman, M. M., & Brink, D. L. (1991). The complete analysis of wood polysaccharides using HPLC. Journal of Wood Chemistry and Technology, 11(4), 447-463.

26. Lines 146 – 150

• What is the purpose of conducting X-ray diffraction? The objective should be clearly mentioned in this section.
• How were crystallinity indices measured? Please include an equation formula or/and cite a reference of the standard followed.
• Why were the samples grounded into powder? It will destroy crystalline regions and most likely will influence crystallinity. In other words, when you ground materials, they become amorphous, thus could not indicate the biodegradation rate of the lunch box.
• It would be better to report the degraded samples' degradation rate by cutting intact test pieces from degraded samples, then conducting x-ray diffraction to measure the crystalline regions.
• This will report the degradation rates by decreasing crystallinity indices over time.

Response:

Thank you very much for pointing this out.

• Crystallinity is a suitable tool for estimating the level of wooden material degradation during weathering. The crystallinity has an important effect on the physical, mechanical and chemical properties of wood-based materials. For example, Young’s modulus, tensile strength, dimensional stability, density and hardness increase with crystallinity [1]. Therefore, the determination of crystallinity may be an approach for understanding the effect of weathering on wood properties. The crystallinity of plant fibers, woody, and bamboo materials is one of the markers used to measure their degrading properties in the classic literature on degradation or weathering.
• we have cited equation in line 150 as "Eq. (2)" and added equation number after the equation.
• As concerning XRD, in fact, the separation of amorphous background from the diffraction pattern of cellulose crystallites can be affected by significant errors related to their small size (usually between 2.5 and 3.5 nm) [1]. The 60 mesh powder is only intended to meet the requirements of the instrument in the laboratory and has no effect on the fiber's crystalline region. The particle size of 60 mesh powder is approximately millimeters, which is far from destroying cellulose's crystalline area, which demands more energy.

[1] Lionetto, F., Del Sole, R., Cannoletta, D., Vasapollo, G., & Maffezzoli, A. (2012). Monitoring wood degradation during weathering by cellulose crystallinity. Materials, 5(10), 1910-1922.

27. Lines 160 – 188 ●Require deep revision in English language. There are major mistakes. For example, "the weight loss rate increased rapidly".

• It would be better if figures were placed in their corresponding section.
• There is no comparison between results from other studies.

Response:

Thank you very much for pointing this out.

• we have revised English language.
• The “results and discussions” have modified according to parts 2.2-2.8
• The results from other studies have added to the text. Please check it.

28. Lines 190 – 202

"The change process had mainly three stages. The first stage was from 50℃ to 200℃, which was mainly the water evaporation stage, including free water and bound water. At this time, the chemical composition was basically unchanged"

• There are no citations of any studies supporting these claims. In the literature review, water evaporation is around 50 – 130° C.

Response:

Thank you very much for pointing this out. For the analysis of the thermal stability, I have updated the text and references. Please check it.

Sometimes the first stage does not appeare due to very low moisture content or minimum weight loss and exhibits the second stage as the first stage [1, 2]. Some researchers [2, 3] have considered the evaporation of moisture content to 200 °C as initial weight loss which corresponds to a maximum weight loss of 10%. In the text, water evaporation is around 50-200° C.

[1] Puglia, D., Monti, M., Santulli, C., Sarasini, F., De Rosa, I. M., & Kenny, J. M. (2013). Effect of alkali and silane treatments on mechanical and thermal behavior of Phormium tenax fibers. Fibers and Polymers, 14(3), 423-427.

[2] Essabir, H., Bensalah, M. O., Rodrigue, D., Bouhfid, R., & Qaiss, A. (2016). Structural, mechanical and thermal properties of bio-based hybrid composites from waste coir residues: Fibers and shell particles. Mechanics of Materials, 93, 134-144.

[3] Monteiro, S. N., Calado, V., Rodriguez, R. J. S., & Margem, F. M. (2012). Thermogravimetric behavior of natural fibers reinforced polymer composites—An overview. Materials Science and Engineering: A, 557, 17-28.

 

29. Figures          ●Figures should be divided and placed into their corresponding section.

Figure 2 (a)         ●The curve should be descending similarly to TGA curves in (d) because it is a mass loss (%).

Figure 2 (b), (e), (d)   ● It was difficult to observe the differences between these figures.

Figure 2 (f)          ● It not clear what is the authors trying to convey.

Figure 3             ●Why figure.3 letters started with "(g)"? It should be “Figure.3(a), (b), (c), (d).”

• It would be better if SEM micrographs, biofilms, fiber expansions, fragmentation, and micro-cracks were labeled.

Response:

Thank you very much for pointing this out. we have revised it all.

30. Lines 293 – 305   ●It would be better if SEM micrographs and figure 4 were placed under this section.

Response:

Thank you very much for pointing this out. SEM micrographs and figure 4 were placed under 3.7 “Microscopic appearance” 

31. Conclusion

    ●The authors claim that bamboo-based lunch boxes displayed excellent degradation performance and degraded the soil in 70 days. However, there is no comparison of the reported results of other biodegradable lunch boxes.

• The results reported did not support the claims made in 333 – 344.  

Response:

Thank you very much for pointing this out.

• we couldn't agree more with you on that. Actually, I did soil degradation tests on polyester lunch boxes and wood pulp lunch boxes. The degradation data from the bamboo fiber lunch box was analyzed, and the other lunch boxes will still be tested. Based on the test data presented thus far, polyester lunch boxes degrade in about 6 months or more, while pulp lunch boxes degrade in about 3 months.
• we have revised the results. Please check it.

 

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I have no further comments.

Author Response

The manuscript has been updated with appropriate language changes.

Reviewer 3 Report

Although credits to the authors for a much-improved manuscript, I believe some significant issues must be addressed. Firstly, an objective comparison between the results of this study and polyester-based lunch boxes. Since the authors claimed in the conclusion: “had the advantages of high strength, good stability, easy and rapid degradation”, however, there is no comparison, particularly in the results section, has been done to support this claim. Furthermore, it is impossible to note peak changes in chemical composition based on FTIR spectra in figure 6(a). Also, I believe the justification for conducting this study could be improved because this work highlights the good biodegradability of bamboo-based utensils compared to biodegradable non-plant fibers utensils. However, other studies of plant fiber possibly show similar biodegradability [ref.21]. Therefore, I suggest emphasizing the high sustainability of bamboo as a source for biodegradable utensils. This should give lay the ground for justification for conducting this study. There are many grammatical mistakes throughout the manuscript, particularly in describing soil burial weight losses that should be fixed, mainly “weight loss rate increased.”

Here is my review point by point

Line 17 “the curve of weight loss rate increased rapidly to slowly to quickly.”

·   ● Please adjust the weight loss curve to descending by making the initial weight (Day 0) 100%, (Day 7) 89.3.7% ect, similarly done for TGA weight loss curves.

·     ●A better way is to describe weight loss numbers using “higher”, “lower”, XX% weight loss,  or weight loss of XX%.

Lines 83 – 86

·  ●This justification must be improved because in ref.20 and ref.21, plant fibers-based biodegradable trays and cups have similar biodegradability.

· ●I suggest emphasizing the specialty of utilizing bamboo fiber. Such as sustainability of bamboo, rapid growth, abundance in China or Asia, and unused renewable materials.

Line 84

·       ●Please change “benn” to “been”

 

Lines 88 – 89 “Not only the safety of fiber lunch boxes without pollution and the characteristics that are easily degraded, but also the strength are the advantages of polyestertype lunch boxes.”

·       I suggest rewriting this sentence because it’s not grammatically sound. Maybe meaning is “natural fiber-based lunch boxes are not only environmentally friendly and biodegradable but also higher in strength compared to polyester-based lunch boxes.”

Line 107

·  ● Please change “37°SR ± 2°SR” to “37± 2°SR”

● Line 109  “pressure resistance”

 

·  ●Do you mean heat-pressing pressure? If so, I suggest a correction.

Line 133 “GB/T 1040.3-2006.”

·  ●Please add a reference to this standard.

Line 142

· ● If possible, please add the coating machine details.

Lines 154 – 167

·   ●Please mention the name of the method followed with its reference at the beginning, before the experimental procedure, because the details are based on Van Soest method.

·  ●Please also indicate if modifications have been made on Van Soest method.

· ●If possible, please separate cellulose, hemicellulose, and lignin contents equations and number them.

Line 209

·  ●Please mention a reference that color changes are caused by an increase in diffuse reflection or conduct diffuse reflectance spectroscopy or other tests. This will be able objectively determine diffuse reflection.

Figure 2

·  ●Please change this figure where the curve is descending, as Figure (5) a TGA weight loss curve. The initial Weight loss should be 100% on day 0, then around 90±% on day 7.

·    ●If possible, change the X-axis legend 7, 14,21 etc., instead of 10,20,30 etc.

 

·   ●Make sure it is clear to the reader that this figure shows weight loss in soil recorded before disintegration. Because after day 56, samples are disintegrated.

Lines 216 – 217 “Only bits and pieces of the debris remained, making it hard to image the entire sample”

·      ●I suggest rewriting this sentence academically.

 

Figure 4

●Please delete the space “--” after day 21 on the X-axis legend.

Lines 261 – 262 “The thermal degradability of lignin and hemicellulose was in the temperature range of 300–450°C and 200–300°C [40].”

·       Please write the lowest temperature ranges first, “200-300°C, and 300 – 450°C”, and rewrite the sentence accordingly.

Table 1

·       How was the initial decomposition temperature determined? It usually is set by a predetermined weight loss percentage—for example, 1wt% or 5wt%.

·       Tc has no significance. Therefore I suggest that the authors note mass loss (%) at endset temperatures taken from Figure 5 (a), but make sure to explain the trend where endset mass loss (%) is higher in degraded samples.

·       Please rewrite Table 1 accordingly.

Figure 6 (a)

·  ●Please enlarge the region of interest to note changes in peaks to support claims made in the results section, For example, changes in the fingerprint region associated with cellulose, hemicellulose, and lignin in samples.

Figure 8 (a)

●Please label SEM micrographs, highlighting to the readers the difference.  

● SEM micrograph on Day 42 seems more intact than the one on Day 0.

 

Figure 8 (b)

·       ●Please capitalize the first letters of words under the Step1,2&3.

 

Lines 342 – 343 “Moisture traveled through the aforementioned capillary structure, where it was bound by hydrogen bonds and van der Waals forces”

·       ●Please provide a reference supporting this claim.

 

Lines 371 – 373 “had the advantages of high strength, good stability, easy and rapid degradation, and so forth. It was a good substitute for a biodegradable polyester lunch box.”

 

·  ●This claim was not supported by comparing results with biodegradable polyester lunch boxes. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx