Agri-Biodegradable Mulch Films Derived from Lignin in Empty Fruit Bunches
and Yao-Tung Lin 2Round 1
Reviewer 1 Report
The authors present a good data set for characterizing films of PVA and lignin, which includes mechanical testing, and water interaction. However, the biodegradability evaluation does not support the claims or show biodegradation. This results can be attributed to moisture lost. Also, there no error bars (this tests are usually run in triplicate).
The tittle says "mulch films" implying that the samples are relevant to the application which is not the case. The samples are made in the lab in grams scale.
The LCA and cost estimation lacks proper rigor. The calculations and assumptions are far from an actual estimate. For example, the functional unit defined as the film needed to cover 6000 m^2 is not used but instead the weight of 2 t/Ha which doesn't allow for a comparison. For conventional PE film the cost to cover the area is closer to $500 than $7200 proposed.
I recommend removing the LCA and cost estimation and rather focus on refining the actual evaluations made. Please find specific comments in the attached pdf.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Dear authors,
the article ‘Agri-Biodegradable Mulch Films Derived from Lignin in Empty Fruit Bunches’ turns out to be innovative and brings a new prospective on use of mulch films biodegradable. Generally, the paper contains some interesting data, it is well-planned and well-written. However, in this reviewer's opinion, there are some minor changes to be made:
Line 70-71: Improve this sentence
Line 107: The Authors perhaps mean 6% (w/v)?
Line 109: the same 80% (w/v)?
Line 111: “room conditions” to “ambient conditions”
Line 112: insert standard deviation for temperature and humidity values.
Line 159-160: ‘The differences in films weights…’ to ‘The differences in their weights….’
Line 162-163: Rewrote this sentence.
Line 256-257: improve this sentence.
Line 368: ‘increased’ to ‘in-creased’
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The researchers discussed the topic of the production of modern films for agricultural applications using mixtures of PVA and lignin. Has the economic factor been taken into account? Will this type of film be too expensive for agricultural use? Remembering and taking into account the production cost of polyvinyl alcohol itself?
Introduction
1. Please supplement with newer literature reports on the amount of tons of plastic in the agricultural sector - at least from 2015 - 2016 and newer (35th Line).
2. Indeed - polyvinyl alcohol is a very good and soluble film-forming polymer, but unfortunately very expensive with its extensive use. Please comment? (45th Line).
Lignin Extraction
1. What was the end product pH? - pH has an extremely important task here in further modifications. Was the product in the form of a concentrated solution? what color? or also solid powder? (102n d Line).
Composite Films Preparation
1. The solvent should not be evaporated in this way due to the release of volatile organic compounds from the synthesis to the atmosphere. Evaporation should only take place with the use of a rotary evaporator (so-called evaporator) (111nd Line).
2. What chamber? failure to provide technical data, name, manufacturer, country of origin, etc. (111nd Line).
Transparency Properties of Films
1. Technical data of the spectrophotometer are not provided (116th line).
Film contact with water 122
Moisture Content
1. Failure to specify the specifics of the device or methodological method - thermogravimetric tests (125th Line).
2. No parameters of the furnace or the manufacturer - unless stated above (125th Line).
Water Solubility
1. “…gravimetrically”. - please describe the process / device methodology (133rd Line).
2.5.3 Water Absorption
1. as above (145th Line).
Soil Biodegradation
1. Provision of the standard etc. (155th Line).
2. as above (161st Line).
3. How was the color change registered? by devices, orgaoleptically? (166th Line).
Fourier Transform Infrared Spectroscopy
1. KBr pellets / film discs are made into FTIR with a press - which one was used? name, manufacturer (185th LIne).
Results and Discussion
Effect of Initial Lignin Content
1. Table 3 shows the results of the alkaline modification or the acid extraction? it is not clearly stated and described in the text-correction (244th Line).
The Film Contacts with Water
1. Since lignin is more hydrophobic, how did films with lignin become more water-soluble? (303rd Line).
2. “…the distortion of the water molecules….” - in what sense? maybe a different orientation of the water molecules ? (320th Line).
Fourier Transform Infrared Spectroscopy
1. No comment is made on the remaining analyzes and explanations on the formation of a co-network between PVA and lignin. Since there is a shift in the absorption bands in the UV / Vis range as a result of a change in the weight fraction of lignin introduced into films, where can one look for an answer to this in FTIR? Which bands and chromophore groups of organic compounds will be responsible for these changes? (397th Line).
Life Cycle Impact Assessment (LCIA)
1. Standard, reference footnote etc.(405th Line).
Environmental Impact of PVA/Lignin film
1. Did these studies take into account the luch population and the impact of foil on human health? If so, what was the population? - no guidelines for research / observation were given (436th Line).
Environmental Impact of PVA/lignin film compared to commercial and biodegradable mulch films
1. Is biodegradable mulose film commercial? - not clearly described (similar to commercial mulose film) and commercial film is synthetic? (444th Line).
2. In what sense? – unclear (447th Line).
3. As above - research done on a representative group of people? (465th Line).
Cost Estimation
1. It is not clear in Table 6 whether it is a lignin extract or a film containing this extract. Similar with commercial lignin (or commercial lignin-containing film)? (480th line).
Conclusions
The conclusions lack a more detailed description of the evaluation of environmental research on individual films, compared to commercial composites. What was the number of samples for estimating the behavior of the film in different environments? What was the time of estimating changes in particular environments? Did these factors affect the final result? (494th Line).
Too many variables, such as in Figure 11, 13, causes a problem in reading the authors' intentions. Which of these indicators were implemented and achieved, because the diagrams show a maximum of 3 to 5 variables.(417th Line, 451nd Line).
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
