Analysis of the Anti-Corrosion Performance of Dextrin and Its Graft Copolymer on J55 Steel in Acid Solution
Round 1
Reviewer 1 Report
The presented study evaluates the anticorrosion effect of dextrin before and after copolymerization on J55 steel in acid solution. In some parts of this article, several grammatical inaccuracies, redundancy of terms, and typos make it difficult for readers to understand, giving the impression that authors did not review before submission. It should be acceptable for publishing after minor revisions if several issues are considered and modified carefully by the authors.
To make some examples: “However, most of the most widely used corrosion inhibitors are mainly chemical synthesis, and most of these corrosion inhibitors have good corrosion inhibition effects.” or “The caprolactam solution was added to the dextrin solution, stirred in a water bath at 75°C for 15 minutes, and finally the monomer caprolactam was slowly added.”
Introduction:
The authors should please review typos and words redundancy.
Material and methods:
Paragraph 2.1: Is the percentage of J55 steel referred to Fe? Moreover, it should be reported Fe quantity instead of “a lot of”.
Paragraph 2.2: Please review typos, words redundancy, and correct reaction balancing on page 2.
Paragraph 2.3: Please review typos and report IR spectra acquisition conditions.
Paragraph 2.4.1: Please define “normal pressure”.
Paragraph 2.4.3: Please report SECM spectra acquisition conditions.
Paragraph 2.4.3: Please report SEM spectra acquisition conditions.
Paragraph 2.4.5: Please report contact angle spectra measurement conditions.
Results and discussion:
Paragraph 3.1: In the Dxt-g-CPL spectrum, the band at 1639 cm-1 is assigned to the CPL carbonyl group. A stronger band at the exact wavenumber is reported in the Dxt spectrum. Please check this, reporting literature in case. Moreover, the authors should check either assignment of C-N stretching and the one for the band at 986 cm-1. Grafting should be evaluated by also using other techniques besides FT-IR.
Paragraph 3.2: Please report figures 4 and 5 respectively as Fig. 4A, Fig.4B, Fig. 5A, and Fig. 5B.
Paragraph 3.3.2: Please report figure 7 as Fig. 7A-F describing the caption.
Paragraph 3.3.3: Please report figure 8 as Fig. 7A and Fig.7B.
Paragraph 4.1: Please report figure 12 as Fig. 12A and Fig.12B.
References:
The authors should please uniform references style.
Author Response
To make some examples: “However, most of the most widely used corrosion inhibitors are mainly chemical synthesis, and most of these corrosion inhibitors have good corrosion inhibition effects.” or “The caprolactam solution was added to the dextrin solution, stirred in a water bath at 75°C for 15 minutes, and finally the monomer caprolactam was slowly added.”
Reply: Modified and marked in the original text.
Introduction:
The authors should please review typos and words redundancy.
Reply: Modified and marked in the original text.
Material and methods:
Paragraph 2.1: Is the percentage of J55 steel referred to Fe? Moreover, it should be reported Fe quantity instead of “a lot of”.
Reply: Modified and marked in the original text.
Paragraph 2.2: Please review typos, words redundancy, and correct reaction balancing on page 2.
Reply: Modified and marked in the original text.
Paragraph 2.3: Please review typos and report IR spectra acquisition conditions.
Reply: Modified and marked in the original text.
Paragraph 2.4.1: Please define “normal pressure”.
Reply: Modified and marked in the original text. "Normal pressure" means that no additional pressure is applied under normal conditions, generally 1atm (101.325kPa).
Paragraph 2.4.3: Please report SECM spectra acquisition conditions.
Reply: Modified and marked in the original text.
Paragraph 2.4.3: Please report SEM spectra acquisition conditions.
Reply: Modified and marked in the original text.
Paragraph 2.4.5: Please report contact angle spectra measurement conditions.
Reply: Modified and marked in the original text.
Results and discussion:
Paragraph 3.1: In the Dxt-g-CPL spectrum, the band at 1639 cm-1 is assigned to the CPL carbonyl group. A stronger band at the exact wavenumber is reported in the Dxt spectrum. Please check this, reporting literature in case. Moreover, the authors should check either assignment of C-N stretching and the one for the band at 986 cm-1. Grafting should be evaluated by also using other techniques besides FT-IR.
Reply: Modified and marked in the original text. Thank you very much for your criticism and correction. In the infrared spectrum of Dxt, there are some strong bands, at 1500-1000cm-1, under normal circumstances it is the bending vibration of the C-H bond. Checking the data shows that there is mostly C-H out-of-plane bending vibration at 1000-650cm-1.
Paragraph 3.2: Please report figures 4 and 5 respectively as Fig. 4A, Fig.4B, Fig. 5A, and Fig. 5B.
Reply: Modified and marked in the original text.
Paragraph 3.3.2: Please report figure 7 as Fig. 7A-F describing the caption.
Reply: Modified and marked in the original text.
Paragraph 3.3.3: Please report figure 8 as Fig. 7A and Fig.7B.
Reply: Modified and marked in the original text.
Paragraph 4.1: Please report figure 12 as Fig. 12A and Fig.12B.
Reply: Modified and marked in the original text.
References:
The authors should please uniform references style.
Reply: Modified and marked in the original text. Thank you very much for your criticism and corrections and suggestions.
Reviewer 2 Report
The manuscript was poorly written, especially in introduction where the authors did not clearly point out the innovation of the topics. The manuscript has a number of grammatical and syntax errors. Please carefully read the manuscript and correct these errors. The authors are required to describe what is new in this manuscript in more detail. Please, point out how your work is different and important in the context of the earlier works.
The synthesis of dextrin graft copolymer is unclear. In section 2 at 2.1. "Preparation of experimental drugs and materials" why do you use the word drugs? The subject of the paper is about anti-corrosion performance of dextrin graft copolymer and not about the use of this grafted copolymer in the preparation of drug delivery systems.
The initiation mechanism of grafting reaction is not correct. Please check the literature for the mechanism of the decomposition reaction of potassium persulfate.
What is grafting yield? What are the optimal conditions to obtain the polymer with the highest grafting yield? The influence of the grafting yield on the corrosion performance is interesting to study.
Other absorption isotherms also needed to be studied in order to draw a more relevant conclusion.
In conclusion, I can’t recommend publication of this paper, but I encourage the authors to rewrite the paper. The English must be improved.
Author Response
The manuscript was poorly written, especially in introduction where the authors did not clearly point out the innovation of the topics. The manuscript has a number of grammatical and syntax errors. Please carefully read the manuscript and correct these errors. The authors are required to describe what is new in this manuscript in more detail. Please, point out how your work is different and important in the context of the earlier works.
Reply: Modified and marked in the original text. Thank you very much for your suggestion. The introduction part of the manuscript of my paper did not clearly express the importance and significance of the research. Therefore, I have strengthened the introduction part. This article mainly studied the anti-corrosion performance of the copolymer of caprolactam grafted to dextrin. Dextrin is a polysaccharide compound, which is environmentally friendly and has a corrosion inhibition effect. The grafted copolymer has more adsorption sites and has stronger adsorption capacity than simple polysaccharides.
The synthesis of dextrin graft copolymer is unclear. In section 2 at 2.1. "Preparation of experimental drugs and materials" why do you use the word drugs? The subject of the paper is about anti-corrosion performance of dextrin graft copolymer and not about the use of this grafted copolymer in the preparation of drug delivery systems.
Reply: Modified and marked in the original text. Sir, I'm very sorry, here is my misnomer. What I want to express here is chemicals, some chemicals used in the synthesis of copolymers. The initiation mechanism of grafting reaction is not correct. Please check the literature for the mechanism of the decomposition reaction of potassium persulfate.
Reply: Modified and marked in the original text. Thank you very much for the teacher’s criticism and correction. I have reviewed the literature and corrected the trigger mechanism.
What is grafting yield? What are the optimal conditions to obtain the polymer with the highest grafting yield? The influence of the grafting yield on the corrosion performance is interesting to study.
Reply: Thank you very much for your suggestions. This grafting scheme is obtained through reference in many documents and continuous experiments by myself. The products synthesized under this condition also have better corrosion inhibition effects. It is possible that the higher the grafting rate, the more caprolactam monomer can be grafted to dextrin, which may be more conducive to the better adsorption of the synthesized copolymer on the surface of the metal, and it also has a better corrosion inhibition effect.
Other absorption isotherms also needed to be studied in order to draw a more relevant conclusion.
Reply: Sir, thank you very much for your suggestions. A lot of literature was reviewed here, and the Frumkin, Temkin and Langumir isotherm adsorption equations were studied. It was verified that the Langumir adsorption isotherm equation was the most consistent with the adsorption process of the Dxt-g-CPL graft copolymer on the metal surface.
In conclusion, I can’t recommend publication of this paper, but I encourage the authors to rewrite the paper. The English must be improved.
Reviewer 3 Report
Summary: The authors prepared dextrin (Dxt) and dextrin-caprolactam (Dxt-g-CPL) polymers and investigated their anti-corrosion properties on J55 steel in 1M HCl solution. The anti-corrosion effects of the polymers are illustrated by both bulk and surface characterization. The authors claim that for both Dxt and Dxt-g-CPL, best anti-corrosion performance is observed at 300 mg/L of polymer. Furthermore, the Dex-g-CPL copolymer shows better anti-corrosion effects than the Dex homopolymer. We have concerns over data interpretation and insufficient evidence for certain claims, which leads to unconvincing conclusions. Therefore, we recommend a revision to address the following concerns:
- Our major concern is with the synthesis and characterization of the Dxt-g-CPL copolymer. The chemistry is poorly described and difficult to follow. The use of FTIR alone to prove successful copolymer synthesis is insufficient. The chemical structure of the copolymer should be analyzed by NMR. The molecular weight of the copolymer should be analyzed by GPC and/or mass spec. This information is critical to support the author’s claim of having a Dxt-g-CPL copolymer.
- Based on Figure 4, the authors claim the best anti-corrosion performance occurs when polymer concentration is 300 mg/L. There is only one data point after 300 mg/L, and it shows a small increase in corrosion activity. It is not clear how one can confidently conclude best performance at 300 mg/L based on this one data point. We suggest additional corrosion experiments pass 400 mg/L to confirm the claim.
- The discussion in section 4.1 regarding adsorption isotherm is very difficult to follow. It is not clear how surface coverage was measured. This experiment is crucial to the determination of the anti-corrosion mechanism, so further explanation is needed.
- We strongly recommend the authors to improve on the English usage. There are many poorly written sentences which make the paper difficult to understand.
Author Response
Summary: The authors prepared dextrin (Dxt) and dextrin-caprolactam (Dxt-g-CPL) polymers and investigated their anti-corrosion properties on J55 steel in 1M HCl solution. The anti-corrosion effects of the polymers are illustrated by both bulk and surface characterization. The authors claim that for both Dxt and Dxt-g-CPL, best anti-corrosion performance is observed at 300 mg/L of polymer. Furthermore, the Dex-g-CPL copolymer shows better anti-corrosion effects than the Dex homopolymer. We have concerns over data interpretation and insufficient evidence for certain claims, which leads to unconvincing conclusions. Therefore, we recommend a revision to address the following concerns:
- Our major concern is with the synthesis and characterization of the Dxt-g-CPL copolymer. The chemistry is poorly described and difficult to follow. The use of FTIR alone to prove successful copolymer synthesis is insufficient. The chemical structure of the copolymer should be analyzed by NMR. The molecular weight of the copolymer should be analyzed by GPC and/or mass spec. This information is critical to support the author’s claim of having a Dxt-g-CPL copolymer.
Reply: Thank you very much pointed out problems and recommendations， I think your suggestion is very important to have my experiment. In the research of this article, infrared spectroscopy was used to analyze the synthesized polymer, and in the weight loss experiment, electrochemical experiment and surface analysis experiment, it can be clearly seen that the corrosion inhibition performance after the addition of the copolymer is obvious. And by comparing the anti-corrosion performance test of Dxt and Dxt-g-CPL, among all the experimental condition variables, only grafting is the variable, so here it can be explained that the copolymer is successfully synthesized and its corrosion inhibitory effect is also obvious.
- Based on Figure 4, the authors claim the best anti-corrosion performance occurs when polymer concentration is 300 mg/L. There is only one data point after 300 mg/L, and it shows a small increase in corrosion activity. It is not clear how one can confidently conclude best performance at 300 mg/L based on this one data point. We suggest additional corrosion experiments pass 400 mg/L to confirm the claim.
Reply: Sir, thank you very much for your suggestion. I think your suggestion is very reasonable. Future experiments will also consider this aspect more. Although there is only one concentration point behind 300mg/L, when the concentration is 400mg/L in this experiment, the concentration is already very high, and the ultimate goal of our experiment is to put into engineering applications. If a higher concentration is required, it may be not conducive to practical applications.
- The discussion in section 4.1 regarding adsorption isotherm is very difficult to follow. It is not clear how surface coverage was measured. This experiment is crucial to the determination of the anti-corrosion mechanism, so further explanation is needed.
Reply: Sir, thank you very much for your suggestions. In the part of the adsorption isotherm, I mainly discuss the Dxt and Dxt-g-CPL adsorption methods. This adsorption method is in line with the Langumir adsorption isotherm equation. Then the standard Gibbs free energy is discussed, from which it can be judged that the adsorption of the corrosion inhibitor on the metal surface is spontaneous. According to the standard Gibbs free energy value, the adsorption method of the corrosion inhibitor on the metal surface can be judged ( Physical adsorption and chemical adsorption). Our surface coverage rate is calculated based on the corrosion inhibition efficiency through the following equation:
Modified and marked in the original text.
- We strongly recommend the authors to improve on the English usage. There are many poorly written sentences which make the paper difficult to understand.
Reply: Okay, thank you very much for your criticism and correction. The English has been modified and edited by a native English speaker.
Round 2
Reviewer 2 Report
The revised manuscript in the current version has been improved and can be read in the easier way. I recommend the paper publication in Processes journal. However the English must be improved.
Reviewer 3 Report
The authors addressed all my comments.
