Experimental Studies on the Phase Separation Behavior of Molten Benzenesulfonate-Modified PET/PA6 Blends

Round 1

Reviewer 1 Report

The submitted paper entitled "Experimental Studies on the Phase Separation Behavior of Molten PET/PA6 Blends" focused on the blend separation phenomenon. My overall opinion of the paper is good. The concept is not new; however, the presented results can be used as a comparative analysis. After major corrections, the paper might be published. Specific comments are presented below. 

The introduction should be expanded; the authors should present the blend separation phenomenon more deeply. The examples of blend compatibilization strategies should be discussed. The discussion on the obtained results should also include references to previous works on this subject, while in the current version, this aspect of the analysis has been omitted.

The concept of the performed rheological study should be supplemented. I suggest conducting time-dependent tests, where the sample will be subjected to constant shear conditions as a function of time.

The phase separation phenomenon might strongly influence the mechanical performance of the polymer blends. It is recommended to perform some mechanical tests.

 

 

Author Response

Please refer to the attache file.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript reports the Experimental studies on the phase separation behavior of Molten PET/PA6 blends, I consider that title did not reflects the work reported, due PET is not used as that, authors report that a cationic dyeable polyester modified with benzenesulfonate  groups, so strictly the polymer is not PET, so it is necessary to change the title. Other specific comments are detailed following:

-First time an abbreviation is written must be defined, for instance SEM, AFM-IR, among others.

-It is necessary to carry out a statistical analysis (for instance with MatLab), due there are several variables in experimental design reported in table 1, table 3 (Molecular weight,  sulfuric acid), and there is not a path for blends prepared. I mean, how can be sure that the variable that affect the phase separation and make a comparison with not a fix variable?

-Subtitle of section 2.4.1 must be Nuclear Magnetic Resonance, not Nuclear Magnetic, please correct.

-In line 102,please correct, must be wavenumber and range 1900-950 cm-1, instead of wavelength, also please correct in all sections with indicate  wavelength for IR results.

-In line 109, indicate that previous studies found that benzenesulfonate is an efficient catalyst for ester-amide exchange, please cite those works.

-Why only report LC4-LA 50-50 is reported with AFM-IR? what about other blends?

-Please explain more about the auburn concept. Also, there is not clear enough how identify IR peaks without a IR spectra reported?

-In line 150 indicate that sample LC4-LA (50-50)-250 was a thermodynamically unstable state, based on which thermodynamic properties is based this supposition?

-Why only report 4 NMR spectra for blends? what about  other blends? Also, why only report a small range for NMR spectra? I mean, usually in C13 NMR the peak for carbonyl ester group is present around 160-180 ppm. I recommend to report the whole range for C13 NMR.

-Data reported in figure 7 and table 5 are the same, please delete table to avoid duplication of data.

-Please follow the Author's instructions of Journal to report references (for instance avoid capital letter in Authors family name of references.

In general I consider that manuscript need to be clarified in experimental design and to be sure about which variable is the dominant factor.

Author Response

Please refer to the attahed file

Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript "Experimental Studies on the Phase Separation Behavior of Mol- 2 ten PET/PA6 Blends" by Ma et al. deals with the analyzing of some commercial modified PET/PA6 blends with different molecular weight of polymers for phase separation. The manuscript is sound and well- organized, it could be accepted after following improvements:

1. The title should contains "benzenesulfonate modified PET" instead of "PET".

2. Line 25: ...with annual output in the tens of millions of tons...requires an reference.

3. Materials and Methods:

Please put the measure unit for molecular weight in Table 1 and Table 2.

It is necessary to have "250" to each sample code?

What kind of samples did you obtain after hot pressing (films/sheets)? Did you use a pressure for pressing? Please complete the Section 2.3.

I suggest the authors to improve the Characterization Method by adding the blends to the specific method for analysis (not all blends were characterized by all methods). 

Line 97: what means "sample stage" and (Pt)?

Line 102: I kindly suggest the authors to check the correctness of wavelength word for IR. Also for Line 118 and Line 120.

4. Results

Please check the  caption for Figure 2 and Figure 3.

Why the authors selected one blend (LC4/LA 50/50) for AFM-IR analysis? I expected to see an IR spectrum. LC4/LA 20/80 blend was not tested, so I recommend to cut this from Table 3.

Line 193: "the an average" - cut "the".

Line 196: "from' instead of "fro"

Figure 4: please complete the caption with the description of (a), (b), (c). How the authors estimated the distribution of dispersed phase for LC2/LA (70/30) and LC8/LA blends while the SEM images were not shown for these blends.

Line 202: what kind of PET was for PET/LA blend? Also for caption from Fig. 5.

Figure 6: I suggest the authors to delete the name of blends inside of graphs and add to caption.

Lines 256, 257, and 259: check the designation of blends.

Figure 7: please check the abscise and the designation of blends (they should be the same as those from Table 3.

About half of cited references are older than twenty years. Although I did not found new references for this PET/PA blends and I suggest the authors to add new references about other types of blends investigated for phase separation, for example: doi:10.11777/j.issn1000-304.2022.22041; doi:10.1080/25740881.2022.2056051; doi:10.1080/25740881.2022.2056051; doi:10.1016/j.polymer.2022.125354, etc. These are necessary to improve the discussion of obtained results.

 

 

Author Response

Please refer to the attached file

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Since some of my comments are taken into account after the paper revision, I have no additional comments on the prepared manuscript.

Author Response

Thanks for your efforts.

Reviewer 2 Report

After review, I wish to thanks to authors for consider the previous recommendations/comments,  the corrected version, this shows a significant improve, but still recommend the statistical analysis using tools such as Matlab to identify the predominant factor in this study.

Author Response

Thanks for your efforts. We will use statistical analysis tools such as Matlab to identify the predominant factor in our next manuscript, in which the relationship between phase separation and mechanical properties will be studied.

Reviewer 3 Report

Thank you the authors for the improved manuscript. I still have few remarks before the publishing of this manuscript, as follows:

1. Why PET/LA(70/30) blend is not described in Table 3? Maybe an adding of this blend as comparative purpose in 2.2. Section clarifies NMR diagram from Fig. 5.

2. Figure 7: I expected to see s-1 or 1/s for abscise instead of /s.

3. Line 289: Table 4? Please check. Also, at Line 324: "These rheological data are listed in Table 5". Table 5 was deleted, please check.

 

Author Response

C1: Why PET/LA(70/30) blend is not described in Table 3? Maybe an adding of this blend as comparative purpose in 2.2. Section clarifies NMR diagram from Fig. 5.

R1: Thanks for the reminding. PET/LA(70/30) blend has been added to Table 3 in the revised manuscript.

 

C2: Figure 7: I expected to see s-1 or 1/s for abscise instead of /s.

R2: Thanks. It is done.

 

C3: Line 289: Table 4? Please check.

R3: Thanks. This sentence has been deleted in the revised manuscript.

 

C4: Also, at Line 324: "These rheological data are listed in Table 5". Table 5 was deleted, please check.

R4: Thanks. This sentence has been revised to “Combining these rheological data with the phase separation results, it can be found that ……”.