Water Vapor Sorption Kinetics of Beech Wood Modified with Phenol Formaldehyde Resin Oligomers
Round 1
Reviewer 1 Report
Dear authors,
your paper was considered carefully and it needs more details:
1- put references for this classification: line 51: "Beech wood is classified as a softwood."
2- Line 79: moisture content for density measurement? "an average density ranging between 620 and 660 kg/m3 were selected for the experiment."
3- Line 85: Please put them all for PF resin: molar ratio, viscosity, density gel time?
4- Use a similar writing format for figures caption
Author Response
Dear Reviewers:Thank you for approving my paper entitled ““Water Vapor Sorption Kinetics of Beech Wood Modified with Phenol Formaldehyde Resin Oligomers”. No. Forests-2573515. You are so serious and your comments are very helpful for revising and improving our paper, as well as the important guiding significance to our researches. In the following, we listed our response after each comment. We modified the manuscript as your advice. Please see the revised manuscript. We appreciate for your warm work earnestly, and hope that the correction will meet with approval.
- put references for this classification: line 51: "Beech wood is classified as a softwood."
Response: We thank the reviewer for the valuable comment. We added the relevant references for the statement"Beech wood is classified as a softwood."
- Line 79: moisture content for density measurement? "an average density ranging between 620 and 660 kg/m3 were selected for the experiment."
Response: Thanks for your suggestion. The moisture content of samples was obtained by a moisture balance equipment. The an average density ranging of samples was obtained by physical properties. The methods and data are described in detail in a previous published paper by my research group “Impact of phenol-formaldehyde (PF) resin oligomers size to mechanical behavior of Beech wood.”
- Line 85: Please put them all for PF resin: molar ratio, viscosity, density gel time?
Response: Thanks for your advice. We add the properties of PF resin (molar ratio, viscosity, density gel time).
4- Use a similar writing format for figures caption
Response: We thank the reviewer for the advice. We rewrite the format for figures caption.
Reviewer 2 Report
The proposed paper describes the modification of beech wood by adding phenol-formaldehyde (PF) resin of different molecular weights and how such modification impacts the sorption characteristic.
I have the following questions and/or comments:
(1) In Table 1, why not indicate the actual amount of free phenol and formaldehyde in A, B and C. Resin D has indicated exact amount?
(2a) Following the morphology of the different materials prepared the use of varying molecular weight and concentrations of phenol-formaldehyde resin using scanning electron microscopic (SEM) analysis can significantly help in the discussion of the water adsorption characteristics, especially the apparent claim on its mechanism of adsorption and desorption. For instance, lines 272-273 [The decrease in the EMC value of modified beech samples can be attributed to the deposition of PF resin in the nanopores of the beech wood cell walls, which reduces sorption sites.] claiming the deposition of PF resin in the nanopores of the beech wood cell walls - best support by SEM micrographs.
(2b) A follow-up question is, how the MW of the PF resin used impact the morphology of these nanopores - which then obviously affect the adsorption and/or desorption characteristics.
I recommend publication with revision.
Author Response
List of responses
Reviewer: 2
Comments to the Author
The proposed paper describes the modification of beech wood by adding phenol-formaldehyde (PF) resin of different molecular weights and how such modification impacts the sorption characteristic.
I have the following questions and/or comments:
(1) In Table 1, why not indicate the actual amount of free phenol and formaldehyde in A, B and C. Resin D has indicated exact amount?
Response: We thank the reviewer for the valuable comment. Resin D has higher solid content. The amount of free phenol and formaldehyde in A, B and C is unstable in experiment. Therefore, amount of free phenol and formaldehyde in resin A, B and C is just a range. The resins used are all industrial experimental products, and the values are consistent with those provided by reagent company.
(2a) Following the morphology of the different materials prepared the use of varying molecular weight and concentrations of phenol-formaldehyde resin using scanning electron microscopic (SEM) analysis can significantly help in the discussion of the water adsorption characteristics, especially the apparent claim on its mechanism of adsorption and desorption. For instance, lines 272-273 [The decrease in the EMC value of modified beech samples can be attributed to the deposition of PF resin in the nanopores of the beech wood cell walls, which reduces sorption sites.] claiming the deposition of PF resin in the nanopores of the beech wood cell walls - best support by SEM micrographs.
Response: We thank the reviewer for the advice. In our previous pape “Impact of phenol-formaldehyde (PF) resin oligomers size to mechanical behavior of Beech wood.” We analyzed morphology of beech sample before and after modification by PF resin with SEM and Light microscopy. In this paper, we emphasis the water vapor sorption of beech wood modified with PF resin.
(2b) A follow-up question is, how the MW of the PF resin used impact the morphology of these nanopores - which then obviously affect the adsorption and/or desorption characteristics.
I recommend publication with revision.
Response: We thank the reviewer for the valuable comment. In previous paper published by author, to gain deeper insight into the efect of PF molecular size on resin penetration and distribution in beech wood, LM investigations were conducted. In the case of specimens treated with diferent concentrations of resin, LM observations showed that the amount of safranin that was absorbed into the wood slightly decreased at higher concentrations. Beech wood treated with the highest concentration of PF resin with PF resin oligomer solutions of various molecular sizes exhibited the highest WPG (approximately 21–24%). Wood is a porous structural material. Adsorption and/or desorption characteristics of beech are closely related to the porous structure of wood. High-molecular-weight PF resins were more uniformly distributed in the specimen and mainly located in the fber lumens. Therefore, MW of the PF resin affect the adsorption and/or desorption characteristics. Once again, we appreciate for your warm work earnestly, and hope that the correction will meet with approval.
