Preparation of High Bio-Content Polyurethane Coatings from Co-Liquefaction of Cellulosic Biomass and Starch for Controlled Release Fertilizers
Round 1
Reviewer 1 Report
1. The content of WO3 in co-liquefied product should be investigated.
2. The reason for using PEG400 should be specified. It is not clear that PEG400 will be hydrolyzed or not.
3. The structure and source of TAE470 should be provided in the material section. The purpose of using TAE470 is not clear.
4. Scheme 1. The bio-polyol contained segment from starch, straw and PEG. The content of each segment in the bio-polyol should be provided.
5. The structure and source of PAPI should be provided in the material section. The purpose of using PAPI is not clear.
6. Lines 112-113: The spraying process was repeated for 4 times till the coating percentage of coated urea was 4%. How the coating rate was determined?
7. Furthermore, the coating percentage was only 4%. The effect of coating on the release of fertilizer may not be significant.
8. Lines 172-174: The solid residue was formed in two ways. One was from the substances in the biomass hardly liquefied, and the other was from the re-polymerized or self-polymerized substances [31]. Figure 1 showed that mass ratio of straw to starch affected the liquefaction rate. The reviewer suggested that the content of residue should be investigated.
9. Lines 190-191: When the reaction materials were all straw, the acid value reached the minimum value of 17 mg KOH g-1. However, from Figure 2 this value clear was not correct. I think it was around 11.
10. Figure 2. The chemistry origin should be provided.
11. Lines 198-200: The calculation of isocyanate index should be provided in the manuscript.
12. The reviewer suggested that the pH of the solution during the hydrolysis process should be monitored.
13. Figure 9. The coating layer should be marked in the SEM.
14. The effect of the bio-polyol preparation method on the thickness of coating layer should be investigated.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors described the Preparation of high bio-content polyurethane coatings from co- 2 liquefaction of cellulosic biomass and starch for controlled re- 3 lease fertilizers
in a very good explanation
but the introduction and conclusion should be improved
Also English editing is recommeneded
Author Response
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Author Response File: 
Author Response.docx
Reviewer 3 Report
Dear Authors,
The present study evaluates a method of manufacturing the high bio-content degradable polyurethane coated fertilizer by converting biomass into bio-polyol and substituting petroleum-based polyol by the co-liquefaction of corn straw and starch in the mixed solvent of polyethylene glycol and glycerol with the aid of an acid catalyst. The research subject is interesting and brings scientific important data in the field, as it deals with a subject that is currently of great interest. Some changes of the manuscript should nevertheless be performed in order to improve its quality. Following specific changes should thus be performed:
Major changes
Please follow the recommended structure in Instructions for Authors (e.g. name of section 2 is Materials and Methods, not Experimental section).
Introduction: You do not offer a well-documented background of your study. You need to compare the purposes of your study with similar ones (which you do not quite present) and afterwards clarify what you bring in novelty. It is very important to state what exactly you bring in novelty in order to express your originality. The purpose of the study needs to be found in the last paragraph and be clearer. This paragraph should not contain materials, nor methods or results. Please add further information and justifications and modify accordingly.
Results and Discussions: In this section, you should also compare your results with similar ones obtained in literature and state once again what your study brings in novelty, this time in terms of results.
All these suggested changes should be performed in order to bring further improvements to the manuscript.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
1. The short form of FTIR, XPS, GPC should be written full form in the abstract. For example “…Fourier transform infrared (FTIR)…” and etc.
2. If only corn straw was investigated in the research, the word of corn should be added before the word straw in the Introduction 68 line and elsewhere.
3. In Part 2 the sentence shrift size of in lines 76-77 “Corn starch was derived from Shandong Dongdu Foods, China. Before being used, they were...” and in lines 79, 80 and 81 “...mg KOH g-1, pH value of 11, TAE470 was provided from Tianjin Petrochemical, China. Polyaryl polymethylene isocyanate (PAPI, Desmodur 44V20L) was supplied by Bayer, Germany.” was different from the shrift size of other sentences in the text.
4. Figure 2. The effect of straw and starch ratio on acid and hydroxyl values, the situation of the mass ration of straw and starch changing from 1:0 to 3:1, and Hydroxyl value first increasing to 388 mg KOH g-1, then decreasing to 1:1, 1: 3 and 0:1 again was not explained.
5. "The hydroxyl values ​​of the bio-polyols were found to range from 270 mg KOH g-1 to 388 mg KOH g-1" was written in the text. But in Figure 2, there is no case about “the hydroxyl values ​​are 270 mg KOH g-1”. This indicator started at about 310 mg KOH g-1.
6. At the end of pages 8-12, the article has a large number of blank spaces. When printing the article, all pages must be complete.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
none
Author Response
We express our sincerest gratitude to the reviewer. We checked the word spell and corrected them. Thanks for your help.
Reviewer 3 Report
Dear Authors,
The present study evaluates a method of manufacturing the high bio-content degradable polyurethane coated fertilizer by converting biomass into bio-polyol and substituting petroleum-based polyol by the co-liquefaction of corn straw and starch in the mixed solvent of polyethylene glycol and glycerol with the aid of an acid catalyst. The authors performed most of the suggested changes after the first round of review. Following specific changes should still be performed:
Major changes
Abstract has more than the 200 words recommended in the Instructions for Authors.
Results and Discussions: I do not see the part where you compare your results with similar ones obtained in literature and state once again what your study brings in novelty, this time in terms of results.
All these suggested changes should be performed in order to bring further improvements to the manuscript.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
