Mechanistic Study of the Synergistic Interaction of Furfuryl Alcohol and Caprolactam in the Modification of Pinus massoniana Earlywood and Latewood
Round 1
Reviewer 1 Report
The paper is interesting and has good scientific merit. However, minor English editing is required.
Some comments for improvement:
Introduction is OK. However the purpose of incorporating CPL with FA should be emphasized more.
Line 77 - 20mm*20mm*300mm, please use this style: 20 mm x 20 mm x 300 mm, make sure there is a space between number and unit.
Line 77 – 80 – the sentence of latewood and earlywood sentence is unclear, please revise.
Line 86 – which lab?
Table 1 – please amend the blanket ( ) style, it seems that the font style is not Palatino Linotype
Please provide justification why this parameter was chosen.
Line 102 – what is the vacuum pressure used?
Line 112-113 – “the CPL curing process was set after the FA curing.” What do you mean?
Line 179-184 – why? Why 50% concentration lead to drastic increase in WPG? Please explain.
Line 194 – “The reason for the higher weight loss by 1.88% (11.3% vs. 9.42%)” when you compare between two percentage value, the difference should be in percentage point. So the difference should be 1.88 percentage points.
Line 219 – ImageJ or Image J? please use it consistently.
Line 228 - “or the curing condition for CPL was harsher than FA” I am wondering why such parameter was chosen and it is comparable?
Line 230 – “CPL-treatment did not make the pits aspirated” how do you comes up with this statement? any proof?
The results and discussion is well- and logically written.
Minor editing of English language required
Author Response
Response to the comments from Reviewer-1
Recommendation: Minor revision.
Comment 1.
Line 77 - 20mm*20mm*300mm, please use this style: 20 mm x 20 mm x 300 mm, make sure there is a space between number and unit.
Response: Per suggestion, the style was revised.
Comment 2.
Line 77 – 80 – the sentence of latewood and earlywood sentence is unclear, please revise.
Response: Per suggestion, the sentence was revised.
Comment 3.
Line 86 – which lab?
Response: Thank you for your comment. the lab is at Nanjing Forestry University, and the info have been added in the manuscript.
Comment 4.
Table 1 – please amend the blanket ( ) style, it seems that the font style is not Palatino Linotype
Please provide justification why this parameter was chosen.
Response: Per suggestion, the style was revised and the justification was provided. P. Pereira et al. used CPL (5wt%-10wt%) to obtain UF resins with long storage stability. (DOI: 10.1016/j.ijadhadh.2019.04.005). P. Lan et al. also concluded that ethylene glycol and caprolactam were added during the synthesis process of melamine formaldehyde (MF) resins to develop a new MF formulation with high flexibility, storage stability, and low formaldehyde emissions that can be used for the impregnation of papers. They also used a low mass fraction of CPL (about 5wt%) as a filler. (DOI: 10.15376/biores.14.4.9916-9927) So 5wt% CPL was chosen in this study. X. Jiang et al. (DOI: 10.3390/polym14214641) and X. Liu et al. (DOI: 10.1007/s00107-021-01784-1) concluded that FA in the range of 30wt%-50wt% is preferable for wood modification.
Comment 5.
Line 102 – what is the vacuum pressure used?
Response: Per suggestion, the vacuum pressure was revised (-95kPa).
Comment 6.
Line 112-113 – “the CPL curing process was set after the FA curing.” What do you mean?
Response: Thank you for your comment. Because the curing temperature of FA is 103℃, the curing temperature of CPL is 240℃. In addition, the curing conditions of furfuryl alcohol and caprolactam are different. Hence, FA is cured first and then CPL.
Comment 7.
Line 179-184 – why? Why 50% concentration lead to drastic increase in WPG? Please explain.
Response: Thank you for your comment. We do not know the exact reason why 50% lead to drastic increase in WPG. It might be that significant higher amount of FA monomers penetrated into cell walls as well as attached on them and polymerized on sites, which was evident in SEM images (shown in section 3.2). The reason will be further investigated in the future.
Comment 8.
Line 194 – “The reason for the higher weight loss by 1.88% (11.3% vs. 9.42%)” when you compare between two percentage value, the difference should be in percentage point. So the difference should be 1.88 percentage points.
Response: Per suggestion, the sentence was revised.
Comment 9.
Line 219 – ImageJ or Image J? please use it consistently.
Response: Per suggestion, the words were revised. The software’s name is ImageJ.
Comment 10.
Line 228 - “or the curing condition for CPL was harsher than FA” I am wondering why such parameter was chosen and it is comparable?
Response: Thank you for your comment. The curing temperature with CPL is about 240℃without catalysts. Since this is the first part in our FA/CPL co-treatment project, we did not use any catalyst to bring down the curing temperature for CPL. The coming up manuscript will focus on the effect of different catalysts on the curing performance of CPL. The curing temperature was much milder when catalysts were introduced.
Comment 11.
Line 230 – “CPL-treatment did not make the pits aspirated” how do you comes up with this statement? any proof?
Response: Thank you for your comment. The sentence was revised. This is a possible result and we will conduct follow-up experiments in the future.
Reviewer 2 Report
Dear authors,
Extensive research was conducted with important insights into the interaction of furfuryl alcohol and caprolactam. However, several remarks are noted.
General questions:
Why did you decide to separate earlywood from latewood? What is the purpose of this approach?
What about taking SEM in a low vacuum? One of the reasons for choosing the mentioned conditions is that samples are recorded without intervention in the appearance of the surface and chemical composition.
Would it be useful to perform thermogravimetric analysis (TGA) to determine the thermal stability or possible volatile components? What about GC-MS?
Have you considered examining the bending strength of such modified wood (incorporated CPL)?
Line
Line 98: -0,1 Mpa? Is it absolute pressure?
Line 128 and 129: 5×1×10. × is more appropriate then * (personal opinion)
Line 187: Hemicellulose decomposes in a lower temperature range (220-315 °C), while lignin decomposes over a broad range of temperatures (150 – 900 °C). Is it possible that mentioned 9,42% weight loss is due to lignin decomposition?
Lines 202 and 219: ImageJ or Image J?
Minor editing of the English language required
Author Response
Response to the comments from the Reviewer-2
Recommendation: Minor revision.
Comment 1.
Why did you decide to separate earlywood from latewood? What is the purpose of this approach?
Response: Thank you for your comment. Because of the large difference in the structure of the earlywood and latewood. In order to investigate the performance difference between earlywood and latewood. It provides a theoretical basis for our subsequent experiments.
Comment 2.
What about taking SEM in a low vacuum? One of the reasons for choosing the mentioned conditions is that samples are recorded without intervention in the appearance of the surface and chemical composition.
Response: Thank you for your comment. Our university does not have the above-mentioned SEM instruments. We'll consider a follow-up experiment in the future.
Comment 3.
Would it be useful to perform thermogravimetric analysis (TGA) to determine the thermal stability or possible volatile components? What about GC-MS?
Response: Thank you for your comment. Because the aim of this experiment is to measure the thermal stability of wood at a lower temperature range (25-320℃), so we just ran DSC experiment. We will use TGA and GC-MS in the following experiments to investigate the degradation performance and chemical changes during the pyrolysis.
Comment 4.
Have you considered examining the bending strength of such modified wood (incorporated CPL)?
Response: Thank you for your comment. Yes, we have. Actually, the bending strength is included in another manuscript that we are working on.
Comment 5.
Line 98: -0,1 Mpa? Is it absolute pressure?
Response: Thank you for your comment. The vacuum pressure was revised (-95kPa).
Comment 6.
Line 128 and 129: 5×1×10. × is more appropriate then * (personal opinion)
Response: Per suggestion, the style was revised.
Comment 7.
Line 187: Hemicellulose decomposes in a lower temperature range (220-315 °C), while lignin decomposes over a broad range of temperatures (150 – 900 °C). Is it possible that mentioned 9,42% weight loss is due to lignin decomposition?
Response: Thank you for your comment. We made the statement based on the conclusion in some literature, which stated that the decomposition temperature of lignin in wood is around 250℃ (DOI: 10.1007/s13399-021-01455-4 & DOI: 10.1080/00102200490428585). We speculated that the effect of lignin might be lower than that of hemicellulose.
Comment 8.
Lines 202 and 219: ImageJ or Image J?
Response: Per suggestion, the words were revised.
