Physical and Mechanical Properties of Plywood Produced with Thermally Treated Pinus taeda Veneers

Round 1

Reviewer 1 Report

The paper is very interesting and in my opinion should be published after some minor observation will be solved. Please find attached the manuscript with my observations.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer. We thank you for the considerations made to the paper. We consider all of them relevant and these have been made.

Reviewer 2 Report

See attachment.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer. We thank you for the considerations made to the paper. We consider all of them relevant and these have been made. However, here are some unmodified but justified points:

1. In the summary and conclusion, it was asked what the main points of the research (results). As stated, for example, not occurring changes in the mechanical properties is extremely relevant, since when the heat treatment is applied in other ways there can be a loss of strength. Therefore, it is possible to perform the treatment without losing material properties, again, unlike what is obtained in other forms of heat treatment;
2. At the end of the introduction, it was said that the reason for doing this research is not correct because it has already been done. However, it is worth noting that it has not been done yet. Only one author mentions that if the treatment is done on the veneer instead of the final product, a greater reduction of properties may occur. He is just concluding something without doing the experimental test. This article tried to remove this doubt and concluded that it did not reduce the properties;
3. Internal bonding was not measured due to laboratory and time limitations. Therefore, it remains open for further research involving this type of experiment;
4. We prefer not to add more images to define the minor and major, since only these two values are important; and
5. Regression models are extremely useful, especially when the coefficient of determination is greater than 70%. In these cases, it is possible to estimate the properties for temperature ranges different from those adopted in this Research.

Reviewer 3 Report

The topic of the research work and manuscript is really interesting and provides new information. However there are some issues to be addressed towards its quality improvement before publication.

In the key words, you included the word CCA (please clarify or correct). The introduction in my opinion could be more adequately cover the theoretical background of this topic (heat treatment of wood, veneers and plywood). Improvement could be implemented in this direction. The authors are recommended to incorporate in the text also significant information from the relevant work entitled "Influence of thermal treatment on mechanical strength of scots pine (pinus sylvestris l.) wood". That would be important to add also a brief comment on the preservation performance of the treated veneers/plywood concerning their biological durability (since a reference has already been made in the abstract about preservation). You should aso refer to the potential application of the generated material of treated plywood (at least in the end of the results discussion or conlusions section). The latin names of species should be in italics format. Common names should be prefared for the repetitions in the manuscript (scientific name once in the first time referred). In lines 36-37, if the quality of this wood species is very high, the motivation of this specific experimental work is being questioned. In line 38, the word "chemistry" needs substitution. In line 48, you better use "Guo et al." (correct this in the rest of the text, when tere are 3 or more authors use the first authors name and "et al."). In lines 60-61, provide examples and references. Be carefull, in the study of Fang et al., densification was deliberately applied by mechanical-thermo treatment (compression) of veneers, which is a different treatent, please clarify in the text.

In line 69, I think that your statement "as it can be seen, the heat treatment is done on the final product (plywood), and the use of this treatment on the veneers has not yet been studied" is not evidensed as true, not even from your own quite superficial state-of-the-art description of the topic (please improve this statement). Do not forget that the heat treatment of the already manufactured plywood would destroy the material integrity, strength etc due to adhesion lines destruction during exposure to heat.

The english language is not properly used in many cases, some syntactical and grammatical errors have been detected in the whole text. Significant information is missing from materials-methods chapter (how many trees used? logged or purchased? density of the veneers/wood of this species?what was the atmosphere of the heat treatment chamber? which was the moisture content of the veneers during treatment?). In line 105, grammatical error. Why did you apply the adhesive only in one side (where did you base this technique?). Whre did you base the pressing schedule of these experimental plywood boards? In 135 line, what kind of ANOVA? In line 118, the word "acclimatized" to be corrected. Why did you use  Brazilian standards, since it was intended to be published in an international journal? To let the research community to repeat your experimental part should search for Brazilian standards, while there are international ones. In the graphs and the whole text, the decimals should be separated with dot and not comma. In Figure 7d, standard deviation values are missing only there. Wy did you choose to check only extractives content (not lignin, cellulose, hemicelluloses) in treated/untreated material? Roughness measurement is not at all referred in the chapter of materials-methods. Not references preferably in conclusions. Results discussion should be more thoroughly and properly prepared. Discuss the proposed applications in conclusions chapter.

Author Response

Dear Reviewer. We thank you for the considerations made to the paper. We consider all of them relevant and these have been made. However, here are some unmodified but justified points:

1. The article entitled "Influence of thermal treatment on mechanical strength of scots pine (pinus sylvestris l.) wood" was not inserted in the introduction because it is more than 7 years old;
2. Regarding the methodology of pressing, bonding, etc, the work of Ferreira et al was taken as a reference, as stated in the text;
3. You were asked about the properties studied. It is possible to perform several types of tests on this material, such as internal bond. However, for this research it was aimed to study only these, mainly due to some laboratory and time limitations; and
4. The Brazilian normative was used because of its ease. Using other standards the same result could be obtained. Furthermore, these results come from a thesis done in Brazil, and therefore using Brazilian norms is relevant.

Round 2

Reviewer 2 Report

Dear autors

Although some issues were not solved, the manuscript has been improved too much. If possible, combine the results and discussion section into one section, then is will be more readable.

 

Author Response

Dear Reviewer Thank you for the immense help with the paper. We are sure that the paper was better presented this way. Please be advised that the discussion of the results and the results were presented in only one item.

Reviewer 3 Report

As I have checked, the revised version of the manuscript, no intense revision and improvement have been implemented in the text. Only some of the comments of the reviewer have been taken into consideration, while most of them were not addressed. I believe that the auhtors should improve the introduction, providing a more comprehensive and integrated state-of-te-art description and clarify the objective and ultimate goals of this experimental work. In line 108, the word "humidity" should be changed into moisture content. The whole paper is too short, there is not proper discussion of the results and no discussion concerning the future applications, as previously commented by the reviewer. Please highlight in the conclusions which is the significance of the findings / meaning of this experimental work relating those with the hypothesis in the end of introduction section.

Author Response

Dear reviewer. I hope you are well and healthy. I would like to inform you that the requested corrections have been made, and we apologize for the corrections not made previously. We have changed the introduction a little, adding the paper you said was important in the first review, and improving the contributions and objective of the paper. We have also changed the way we present the results, as you and the other reviewer said. Finally, we tried to improve the conclusions, in which we started with the main contribution and then put in items the other points achieved. See if it is better this way, and if you need to change anything else, we are at your disposal. We thank you for your willingness to make our paper even more relevant.