A Practical Approach for Data Gathering for Polymer Cure Simulations

Round  1

Reviewer 1 Report

This paper describes the cure of a polymer with unknown chemical composition. This is a well-organized and well-illustrated paper. It makes a valuable contribution to knowledge and understanding the curing process of polymer, which is a complicated process where a series of chemical reactions have been activated. I recommend its publication after minor revision.

1. The authors should discuss other methods used by other authors for data gathering for polymer cure simulations. Should be clearer in the manuscript the strengths of this method.

2. There is a mistake in the text of figure 1, it is not Q_s and Q_s, it is Q_s and Q_r .

Author Response

Dear reviewer,

Thank you for your letter and constructive and valuable comments concerning our manuscript entitled “A Practical Approach For Data Gathering For Polymer Cure Simulations”. We have studied your comments carefully and made corrections which we hope meet with your approval. We answer your questions/comments in detail in the following text.

1. The authors should discuss other methods used by other authors for data gathering for polymer cure simulations. Should be clearer in the manuscript the strengths of this method.
Response: Since DSC is a well developed and understood, cheap and fast method to analyze the curing process of a polymer, it is almost exclusively used to do this task. This is reflected in the huge amount of publications using this method.

However, other methods do exist and we have added literature references and a paragraph in the beginning of section 2.1 in which we briefly discuss some.

Lines 67-73:
"Several techniques exist to investigate the curing of polymers. Raman or infrared spectroscopy [30–33] allow investigation of the reaction mechanisms. However, these techniques can not analyze the often very weak signals at high conversion. Measuring the dielectric properties (utilizing DEA) [33] or the change of the internal structure (using ultrasound) [34,35] of the polymer are other methods to characterize the curing process. However, these provide the user not with thermal data.
Judging from the literature curing characteristics are most often measured with Differential Scanning Calorimetry (DSC)."

We have also included a paragraph regarding other methods how to arrive at the kinetic function or how to simulate the curing process at the end of section 2.1.

lines 118-126:
"If the chemical composition of the constituents and the chemical pathways are known, it is possible to arrive at the kinetic function by studying the rate equations of the underlying chemical reactions [58,59]. However, this research was done for the practical case where no detailed information of the involved chemicals was available (c.f. section 5.2).

Two other methods shall be mentioned which enable a user to simulate the curing process of a polymer: molecular dynamic calculations [60] or thermodynamic frameworks [61]. However, these are rather involved, require extensive mathematical frameworks, can not easily be used in standard finite element software and are not suitable for the simulation of large structures with todays computational technology."

2. There is a mistake in the text of figure 1, it is not Qs and Qs, it is Qs and Qr.
Response: Thank you for making us aware of this mistake. We have corrected it.

We really hope these modifications can meet with your approval.
Thank you very much.

Yours Sincerely
Søren Heinze, Andreas Echtermeyer

Reviewer 2 Report

The submitted manuscript aiming to predict the curing process of polymers whose chemical composition is unknown or not completely known. The Introduction is well detailed despite in some points the literature reference can be updated (see attached .pdf). The used procedure is clearly and well inserted in the pre-existing literature about kinetics of curing. DSC technique is also well described (I just suggested only an upload of references regarding the accuracy). The manuscript presents some mistakes (I suggest to define abbreviation always the first time is used) and the presence of typos suggests that probably a more accurate revision before submission would have been appropriate (see attached .pdf). Anyway, the results are interesting and worth of publication. Please focus on the suggestions highlighted in the attached .pdf file with particular care to the correct use of decimal places in E_a values (in my experience it is very difficult that such a value of Activation energy could have a standard deviation less than ± 2, thus it is no meaning to report decimal place). According to these changes and a proof reading to improve English (in particular a better use of the punctuation), I think that the manuscript can be published on Applied Sciences.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thank you for your letter and constructive and valuable comments concerning our manuscript entitled “A Practical Approach For Data Gathering For Polymer Cure Simulations”. We have studied your comments carefully and made corrections which we hope meet with your approval. We answer your questions/comments in detail in the following text.

Language errors have been corrected silently.

1. Does the introduction provide sufficient background and include all relevant references? => Must be improved
Response: Since DSC is a well developed and understood, cheap and fast method to analyze the curing process of a polymer, it is almost exclusively used to do this task. This is reflected in the huge amount of publications using this method.

However, other methods do exist and we have added literature references and a paragraph in the beginning of section 2.1 in which we briefly discuss some.

Lines 67-73:
"Several techniques exist to investigate the curing of polymers. Raman or infrared spectroscopy [30–33] allow investigation of the reaction mechanisms. However, these techniques can not analyze the often very weak signals at high conversion. Measuring the dielectric properties (utilizing DEA) [33] or the change of the internal structure (using ultrasound) [34,35] of the polymer are other methods to characterize the curing process. However, these provide the user not with thermal data.
Judging from the literature curing characteristics are most often measured with Differential Scanning Calorimetry (DSC)."

We have also included a paragraph regarding other methods how to arrive at the kinetic function or how to simulate the curing process at the end of section 2.1.

lines 118-126:
"If the chemical composition of the constituents and the chemical pathways are known, it is possible to arrive at the kinetic function by studying the rate equations of the underlying chemical reactions [58,59]. However, this research was done for the practical case where no detailed information of the involved chemicals was available (c.f. section 5.2).

Two other methods shall be mentioned which enable a user to simulate the curing process of a polymer: molecular dynamic calculations [60] or thermodynamic frameworks [61]. However, these are rather involved, require extensive mathematical frameworks, can not easily be used in standard finite element software and are not suitable for the simulation of large structures with todays computational technology."

2. in some points the literature reference can be updated
Response: We are aware that some of the literature references are of older age. We've tried to provide the groundworks (e.g. Arrhenius, Fava, Pysiak, Vyazovkin) and good theoretical and practical overviews (e.g. van der Plaats, Höhne, Flynn, Schawe, Vyazovkin) of the used techniques. The former are naturally older references and the latter also often come into existence not too long after a method was developed and got more widely used. However, we also provide references to newer publications which utilize these techniques and we hope this is sufficient.

3. the correct use of decimal places in Ea values […]

Response: This is of course right and we have changed it.

4. why do you not report the symbol for conversion?

Response: We do report it in the first sentence directly after the introduction:
"The conversion α (or degree of cure) is the amount […]"

However, thank you for making us aware of this, we have included the symbol in the captions of figure 5 and 6.

We really hope these modifications can meet with your approval.

Thank you very much.

Yours Sincerely
Søren Heinze, Andreas Echtermeyer