Processing and Evaluation of a Carbon Fiber Reinforced Composite Bar Using a Closed Impregnation Pultrusion System with Improved Production Speed

Round 1

Reviewer 1 Report

Check the attached file.

Comments for author File: Comments.pdf

Author Response

Thank you for your helpful comments. We have revised the manuscript following your comments. Please check the attached file and revision form. 

Author Response File: Author Response.pdf

Reviewer 2 Report

 

The references  17, 19 is not cited in the text.

Please check instructions for editing the tables.

At figure 7 the curve is below the image not in lateral.

 

Author Response

The references 17, 19 is not cited in the text.

> The references 17, 19 are cited in section 2.2 following the sentence ‘In the case of using only cylinder pins, previous studies show that the cylinder distance and height are variables of the fiber spreading’ (In the revised version, 17 and 19 were replaced with 19 and 21 respectively)

Please check instructions for editing the tables.

> Thank you for your helpful comment. We have edited all tables according to the instructions.

 At figure 7 the curve is below the image not in lateral.

> The ‘lateral’ mentioned in the text means transverse direction of unidirectional fibers. Therefore, fig.7 shows the surface roughness of composites in the transverse direction. To avoid confusion, we have replaced ‘lateral‘ with ‘transverse’ in the manuscript.

Reviewer 3 Report

Very comprehensive research work for an epoxy resin-based carbon fiber reinforced composite (CFRP) bar pultrusion system

Author Response

Thank you so much for your review comment. It's an honor to hear from you.

Reviewer 4 Report

The authors introduce a study on an epoxy resin-based carbon fiber reinforced composite bar pultrusion system using a closed impregnation with improved material properties and process speed compared to the same bar prepared using a traditional open bath pultrusion system. I have carefully read the manuscript, and I found that this is an interesting work with promising results, and the structure and logic are good. I recommend this work to be published in this journal after some major revisions, since there are still some unclear points in the current manuscript. My comments listed below may help the authors further improve their work:

(Section 1. Introduction)

Some recent reviews on fibre-reinforced polymer structures should be cited: Fibers 2022, 10(3), 27; https://doi.org/10.3390/fib10030027. Composites Part B 191 (2020) 107958; https://doi.org/10.1016/j.compositesb.2020.107958.

Line 30 and 31: The sentence “which contain carbon fibers as the reinforcemet” is redundant. I suggest to remove it.

(Section 2. Materials and methods)

Characterization techniques methods completely missed. Describe in detail the experimental procedures, instruments and characterizations in this section and not in the Results.

(paragraph 2.1)

Line 81 and 82: The sentence “thereby improving the mechanical properties” is not yet supported by experimental results at this point of manuscript. It should be remove.

Line 95 and 98: It would be more appropriate write Fig. 2a and Fig. 2b instead of Fig. 2 left and Fig. 2 right.

Line 124 and 127: It would be more appropriate write Fig. 3a and Fig. 3b instead of Fig. 3 (top)and Fig. 3 (bottom).

(paragraph 3.1)

In Fig. 5 make the dotted line (related to the required viscosity at 400 mm/min) more visible.

(paragraph 3.2.1)

In Fig. 6 make the scale bars clearer changing color and enhance dimension.

(paragraph 3.2.2)

In Table 4 insert the standard deviations to the average values.

(paragraph 3.2.3)

Since modulus is a fundamental mechanical property for composites, it would be very interesting report it for each sample. Do you have that data measured through three-point bending test?

In Table 6 insert the standard deviations to the average values.

The morphological analysis by means scanning electron microscope (SEM) should be added and discuss to strengthen the conclusion about the improved impregnation in Process #2 and #3. Cryo-fractured surface of each sample should be investigated, in particular observing the matrix-fiber interface.

Author Response

The authors introduce a study on an epoxy resin-based carbon fiber reinforced composite bar pultrusion system using a closed impregnation with improved material properties and process speed compared to the same bar prepared using a traditional open bath pultrusion system. I have carefully read the manuscript, and I found that this is an interesting work with promising results, and the structure and logic are good. I recommend this work to be published in this journal after some major revisions, since there are still some unclear points in the current manuscript. My comments listed below may help the authors further improve their work:

(Section 1. Introduction)

 

Some recent reviews on fibre-reinforced polymer structures should be cited: Fibers 2022, 10(3), 27; https://doi.org/10.3390/fib10030027. Composites Part B 191 (2020) 107958; https://doi.org/10.1016/j.compositesb.2020.107958.

> Thank you for your helpful comment. We have added the two papers mentioned above as the references ([11],[12]) in the section 1. Introduction.

Line 30 and 31: The sentence “which contain carbon fibers as the reinforcemet” is redundant. I suggest to remove it.

> Thank you for your helpful comment. We have removed and edited the above sentence following your comment.

(Section 2. Materials and methods)

 

Characterization techniques methods completely missed. Describe in detail the experimental procedures, instruments and characterizations in this section and not in the Results.

> Thank you for your helpful comment. We have added the 'section 2.3 Characterization method' in section 2.

(paragraph 2.1)

 

Line 81 and 82: The sentence “thereby improving the mechanical properties” is not yet supported by experimental results at this point of manuscript. It should be remove.

> Thank you for your helpful comment. We have removed the above sentence following your comment.

 

Line 95 and 98: It would be more appropriate write Fig. 2a and Fig. 2b instead of Fig. 2 left and Fig. 2 right.

> Thank you for your helpful comment. We have replaced ‘Fig. 2 left‘ and ‘Fig. 2 right with ‘Fig. 2a’ and ‘Fig. 2b’

 

 

Line 124 and 127: It would be more appropriate write Fig. 3a and Fig. 3b instead of Fig. 3 (top)and Fig. 3 (bottom).

> Thank you for your helpful comment. We have replaced ‘Fig. 3 (top)‘ and ‘Fig.3 (bottom)’ with ‘Fig. 3a’ and ‘Fig. 3b’

 

(paragraph 3.1)

 

In Fig. 5 make the dotted line (related to the required viscosity at 400 mm/min) more visible.

> Thank you for your helpful comment. We have edited the dotted line more visible in Fig. 5 (In the revised version, Fig. 5 was replaced with Fig. 6)

 

(paragraph 3.2.1)

 

In Fig. 6 make the scale bars clearer changing color and enhance dimension.

> Thank you for your helpful comment. We have edited the scale bars in Fig. 6. (In the revised version, Fig. 6 was replaced with Fig. 7)

 

(paragraph 3.2.2)

 

In Table 4 insert the standard deviations to the average values.

> Thank you for your helpful comment. We have added the standard deviation values in Table. 4.

 

(paragraph 3.2.3)

 

Since modulus is a fundamental mechanical property for composites, it would be very interesting report it for each sample. Do you have that data measured through three-point bending test?

> Yes, we performed the three-point bending test and the maximum bending strength values were shown in Table 6. In addition, the method of three-point bending test was newly described in section 2.3.3.

In Table 6 insert the standard deviations to the average values.

> Thank you for your helpful comment. We have added the standard deviation values in Table. 6

 

The morphological analysis by means scanning electron microscope (SEM) should be added and discuss to strengthen the conclusion about the improved impregnation in Process #2 and #3. Cryo-fractured surface of each sample should be investigated, in particular observing the matrix-fiber interface.

> We have observed the surface of each specimen (Process #2 and #3) using SEM and added the results in Fig. 8. The description of the SEM images was also added to section 3.2.1.

 

Round 2

Reviewer 4 Report

The authors have edited the manuscript with my suggestions and answerd properly all my comments. So, I am happy to recommend this work to be published in this journal.