Study on Improving the Fixation Rate of Impregnated Poplar Wood with Maltodextrin and 1,3-Dimethylol-4,5-Dihydroxyethyleneurea

Round 1

Reviewer 1 Report

Manuscript 559328 by Cai et al. presents the impregnation of poplar wood for the purpose of fixation.

Some issues are detailed below:

1.       The language must be improved throughout the whole manuscript. You should seek the advice of a native English-speaking colleague or use the available commercial services for this purpose. You should also bear in mind to modify the multitude of non-scientific expressions and terms.

2.       The introduction part:  it needs to be extended and modified.

For example “It has the advantages of fast growth rate, high yield, and a short harvesting period, which meets the market demand but the characteristics of low density, uneven distribution of moisture content, and poor mechanical properties markedly affect its service life” I disagree, there are wood species with high density. I think the authors should focus more on the mechanical properties, moisture absorption and dimensional changes related to that, as well as low resistance to biocidal factors (speaking about the more commonly used commercial wood species). “After resin impregnation of wood, the wood is dried to remove moisture and solidify.”- this is unclear, and it needs extensive discussion. Not all impregnation processes make use of polymerization/polycondensation of the resins inside the wood cell wall. “low sweetness, low viscosity, low odor, and low browning reaction” -unclear, explain more these properties. What has sweetness to do with textiles and wood impregnation? How does MA affect the resistance of wood to biological factors?

„the addition of ZnCl2 ensured that the DM remained clear” -this part is unclear. It is not straightforward what MA and ZnCl2 would bring as benefit. The purpose of this study (as it is currently described) is very unclear.

Figure 1 should go to the experimental part.

3.       Experimental: the whole experimental part regarding the starting material(s) and the impregnation process is unclear and it does not allow an independent researcher to reproduce the experiments.

4.       Leaching cycles: the discussions based on absorbance values (what wavelength?) are insufficient. You should at least perform AAS to determine Zn2+ leaching (or spectrophotometry, if not available), TOC analysis and/or spectrophotometric lignin content determination

5.       Wettability: it is useful to determine also the surface energy of the samples for this discussion, not only their water wetting angle. If not available, at least a kinetic of the water contact angles should be given (variation of CA with time until an equilibrium is reached).

Author Response

For the response letter , please find the attached file.

Author Response File: Author Response.doc

Reviewer 2 Report

Overall the paper is very interesting, the results are well presented and thoughtfully discussed

Introduction- The introduction covers the most important aspects of the theme. However there is a lot of work done by Prof. Holger Militz group that is not mentioned here.

Material and methods

This section seems adequate.

Results

The figures are difficult to understand in black and white printing and for example in Figure 3 I suggest to put the order of the series equal to the order of the WLR. It should be 103, ZC 103, ZC120 and 120. There is some confusion on the description of WPG and WLR results. For instance Line 204 “The curing efficiency of 120 was the highest and the WLR was in the range of 27.85% to 35.55%”. This cannot be correct since the line for 120 never goes up to 30%. These values seem to be ZC 120. Also in line 218 “120 had the highest WLR, which was 59.15%, 50.71% and 32.85%, respectively, compared with the 103, ZC-103, ZC-120 treatments????? These values should be for 103. Please rephrase or explain this part. In Figure 6 there are 6 lines but in the description there are 8, also there is nothing saying what the control is in figure 6b. Without being sure what I am seeing I cannot comment on that! Line 270 “When the temperature rose to 103 ℃  and 120℃, the peaks at 3330 cm-1 decreased slightly in groups 3-6, indicating that the  polycondensation reaction of the hydroxyl group (O-H) in the MA and DM” I cannot see this in figure 6 and I don´t know which lines are. Most of this part, with this figure, I cannot see any of the variations stated. Line 393 “The degree of activity and linkage of the active chemical groups in the wood changed, hydrogen bonding occurred, the connection between the microfibrils was broken, and the catalyst accelerated the hydrolysis of the hemicellulose; drying and high temperature destroyed the linkage between the cellulose and resulted in a decrease in the bending strength” The authors should have something to support this conclusion or it will only be a guess. From line 400 something happen to the format

Author Response

For the response letter , please find the attached file.

Author Response File: Author Response.doc

Reviewer 3 Report

The research is reasonably interesting, although it has to be included in the category of “case study”, more correctly.

Abstract

The abstract has too technical parameters. Please, reduce data and explain better the study to improve the comprehension of the work. I'll suggest to add the aim of the study.

Keywords

Words from the title should not be used as keywords.

Introduction

Line 35. “wood from planted…”. Please explain better the concept of wood. Not all tree planted have fast growth rate or short harvesting period. What kind of trees?

Lines 76-86. The authors explain better the aim of the study and the different from compared studies cited precedent. The use of spectrophotometer must be moved in Experiment.

Introduction section is not correctly complete; too long sentences about chemical and treatment aspects and too short to describe the aim of the paper.

Experiment

Line 93. Why were used these measures: 20 mm × 20 mm × 20 mm (L×T×R), 30 mm × 20 mm × 20 mm (L×T×R), and 93 300 mm × 20 mm × 20 mm (L×T×R), respectively. There are norms?Standards?

Line 101. Capacity of vacuum tank?

Line 107. Why the treatment duration was of 48 h? Is there a reference or is your opinion about this time of the tests?

The experiments have a reference to confirm the correctly method used?

Line 118. Why was used 20 replicates. Please add your motivation and explain the accuracy of the tests. I consider 20 specimens not sufficient. The same comments about the number of replicates for 2.4/2.5/2.6 and 2.7

Results

Lines 400-417. Different size of the text.

Line 448. Remove the point after 3.

Line 451. Good is your opinion? Or there is a scale of values?

In results and discussion paragraph there is not a comparative analysis with other study,

Conclusion

Chapter Conclusion is not correct for this type of journal. The conclusions should be written comparing objects of the study and the results obtained. The conclusions repeat the results, not well focused on your findings and know is possible to develop this research. The conclusion is quite short basically including the results. More future developments and conclusions should be considered.

Author Response

For the response letter , please find the attached file.

Author Response File: Author Response.doc

Round 2

Reviewer 1 Report

I feel that the manuscript was improved by the authors and it can be considered for publication in Applied Sciences journal.