Natural Fiber Composite Filaments for Additive Manufacturing: A Comprehensive Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

I believe that your review has interesting information, but some questions that arose while reading it should be clarified:

1. Lines 135-136: The sentence needs clarification regarding the characterization of cellulose as long, thin rods.

2. Lines 141-142: correct the phrase that lignin helps transport water and is also hydrolyzed in concentrated hydrochloric acid, is soluble in concentrated hydrochloric acid. Lignin as a hydrophobic aromatic substance dissolves but under certain conditions in other solutions.

3. Line 143: The term "pectin" also needs clarification. Pectin are only a small specific fraction of polysaccharides, not all heteropolysaccharides. And not only they provide flexibility to plants.

4. Line 144: The phrase "A variety of alcohols are used to make wax" also needs clarification. Alcohols are not used to make of waxes, but for their extraction from plant raw materials. By the way, extractions are not only waxes, which the authors should point out.

5. Line 157: Define the term "volume friction". Perhaps you meant “volume fraction”.

6. Figure 2 needs to be clarified, in particular, it is logical to attribute thermal stability to the thermal properties of NFRCs, and instead of it in the physical properties add, for example, electrical conductivity.

7. The numbering of advantages in Figure 3 is better for the convenience of readers to be shown in a time line.

8. You should add hair (fur) to classification of natural fiber in Figure 4, and ceramic and metal fiber to mineral fibers.

9. In Figure 7 fix Volva on Volvo.

 Best regards,

Reviewer

Author Response

Lines 135-136: The sentence needs clarification regarding the characterization of cellulose as long, thin rods.

Response: Thank you for your suggestion. The sentence is changed to "Plants typically store cellulose as a linear, ribbon-shaped polymer of glucose."

Lines 141-142: Correct the phrase that lignin helps transport water and is also hydrolyzed in concentrated hydrochloric acid, is soluble in concentrated hydrochloric acid. Lignin, as a hydrophobic aromatic substance, dissolves but under certain conditions in other solutions.

Response: Thank you for pointing that out. A complex hydrocarbon polymer called lignin gives NFRC strength, facilitates water transport, and resists most microbial attacks. It is hydrophobic, hydrolyzes in concentrated hydrochloric acid, and is easily oxidized.

Line 143: The term "pectin" also needs clarification. Pectin is only a small specific fraction of polysaccharides, not all heteropolysaccharides. And not only do they provide flexibility to plants.

Response: Thank you for your clarification. The sentence is changed to "Pectin is a heteropolysaccharide that gives flexibility to the cell wall of plants and is used as a thickener that binds substances."

Line 144: The phrase "A variety of alcohols are used to make wax" also needs clarification. Alcohols are not used to make waxes but for their extraction from plant raw materials. By the way, extractions are not only waxes, which the authors should point out.

Response: Thank you for your observation. The sentence "A variety of alcohols are used to make wax. Substances identical to oil and wax are applied to their surface to conserve fibers" is removed from the manuscript.

Line 157: Define the term "volume friction." Perhaps you meant “volume fraction.”

Response: Apologies for the typo error. We edited the term to "volume fraction." Thank you for bringing it to our attention.

Figure 2: Needs clarification, in particular, it is logical to attribute thermal stability to the thermal properties of NFRCs, and instead of it in the physical properties, add, for example, electrical conductivity.

Response: Thank you for your feedback on Figure 2. We revised the Figure to clearly distinguish thermal stability as a critical property of the filament. It's important to note that electrical conductivity is not applicable in our specific filament composition, as it is primarily composed of polymers. We appreciate your input and ensure our representation accurately reflects the pertinent properties of our material.

The numbering of advantages in Figure 3: Better for the convenience of readers to be shown in a timeline.

Response: Thanks for reading and providing valuable comments. The numbering in the picture is inserted in Figure 3. We appreciate your suggestion for improved reader convenience.

You should add hair (fur) to the classification of natural fiber in Figure 4, and ceramic and metal fiber to mineral fibers.

Response: The given information is added in Figure 4. Thank you for enhancing the completeness of our classification.

In Figure 7, fix Volva on Volvo.

Response: Thanks for finding a typo error in the image. The same was rectified in Figure 7. Your keen eye for detail is much appreciated.

Once again, we sincerely appreciate your thorough review, and we believe these revisions significantly improve the clarity and accuracy of the manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract provides a good overview of the topic. It mentions the "need for unifying performance measures and processing parameters," but it doesn't provide specific recommendations that arose from the research.

 

Section 3.1 uses technical terms like "Rule of Mixture theory" and "alkali and silane pretreatment" without providing explanations. A brief explanation or definition of such terms would enhance comprehension, especially for non-specialist readers.

 

In Section 3.2, including figures or tables to visualize temperature ranges and weight loss during decomposition would help readers grasp the concepts more easily.

 

In Section 6, the study includes some grammatical issues and problematic phrases. For example, "a substantial decrease in thermal stability in natural fiber composites" could be made clearer by rephrasing. By addressing these points, it can be created a more reader-friendly and academically robust manuscript.

 

In Section 7, the phrase "There's a pressing need for interdisciplinary collaborations – bridging material scientists, manufacturing experts, and environmentalists to approach holistically" is somewhat vague. It would be more effective if it clarified what specific goals or objectives such interdisciplinary collaborations should have. The conclusion could benefit from a statement about the broader impact of the research. How will the findings discussed in the paper contribute to the field of materials science or sustainable manufacturing?

 

 

 

Comments on the Quality of English Language

 Moderate editing of English language required.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The aim of the paper is very intresting and contain many scientifique results related to the use of natural fibers as charge in such polymers. Also the use of this type of charge in additive manufactoring is a promising issue in the polymer composites applications. 

I think the paper is good to be published in its actual form in the journal.

Comments on the Quality of English Language

The quality of whriting is good and comprehensive.

Author Response

The aim of the paper is very intresting and contain many scientifique results related to the use of natural fibers as charge in such polymers. Also the use of this type of charge in additive manufactoring is a promising issue in the polymer composites applications. 

I think the paper is good to be published in its actual form in the journal.

Thank you very much for appreciating the present work, however, we made some changes in the article as other reviewers suggested 

Reviewer 4 Report

Comments and Suggestions for Authors

This paper presents a valuable overview of natural fiber filament for additive manufacturing technology. Addressing the comments below will further strengthen the clarity and impact of the review research.

 

1.      The Abstract should be rewritten. What is the objective and novelty of this work? Why 3D printing of natural fibre composite is important? Is there any specific application for this material?

2.     Currently, material extrusion (MEX) is referred to as FDM and FFF. It is suggested to indicate MEX filament and printing instead of them throughout the paper. Refer to the references below for more information.

 

 [a] Experimental study on mechanical properties of material extrusion additive manufactured parts from recycled glass fibre-reinforced polypropylene composite. Composites Science and Technology, 2023, 110125.

[b] Mechanical and thermal study of 3D printing composite filaments from wind turbine waste. Polymer Composites, 42(5), 2021, 2305-2316.

  [c] Recovery of Particle Reinforced Composite 3D Printing Filament from Recycled Industrial Polypropylene and Glass Fibre Waste. Proc. World Congr. Mech. Chem. Mater. Eng, 2022, 177, 3-4.

3.     How has the exploration of NFRPCs contributed to bridging the gap between sustainability and material performance?

4.     What are some of the advantages of natural fibers in terms of their impact on machinery and skin irritation compared to synthetic fibers

5.     In which industries are natural fiber commonly used, and how does it serve as a cost-effective alternative to materials like glass fiber?

6.     How do chemical treatments, such as alkaline treatment, silane treatment, etc., impact the adherence of the matrix to NFRC and its hydrophilicity?

7.     What are some common factors that lead to variances in mechanical properties in natural fiber composites, and how can these deviations be attributed to different aspects of the manufacturing process?

8.     It is recommended to provide an overview description of the tensile strength, flexural strength, and impact strength for natural fiber composites as depicted in Table 1.

 

9. The conclusion is too short. Use bullets in Conclusions to emphasize the main achievements of the paper.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

While the objectives are mentioned, they could be stated more explicitly to guide the reader's understanding. Clearly outline the specific research questions or hypotheses being addressed.

While the study mentions industries globally grappling with environmental concerns, providing specific examples or global trends related to the adoption of sustainable materials could enhance the relevance and impact of the research.

Some phrases, such as "groundbreaking findings" and "notable development," could benefit from more precise language or concrete examples to substantiate these claims.

The conclusion should be crafted in a more academically formal style.

Author Response

Please see the attachment

Author Response File: Author Response.pdf