Time and Spatially Resolved Operando Small-Angle X-ray Scattering Measurements during Injection Moulding of Plastics

Round 1

Reviewer 1 Report

This study investigated the time and spatially resolved operando by using small-angle X-ray3 scattering measurements. This is an interesting project which involve high energy physics and injection molding process. However, several typos. My comments are as follows,

1.      Are you using extrusion or injection process to push polymer melt into the cavity? It is very hard to tell from your experimental system on Figure 2. You need runner and gate on the mold for injection molding process.

2.      Figure 6 intesity -> Intensity or intensity?

3.      The plastic cools and becomes solid after passing through a glass transition or crystallising to form a semi-crystalline solid. -> This is a wrong statement, There are two kinds of thermal plastic polymer, one is amorphous and another is semi-crystal. After cooling, they will return to their original state.

4.      Please unify intensity and intesity on your manuscript 

5.      Line 335: Plastic -> melt, Plastic is a general term for solid pellette.

6.      Please put equation number right after the equation. Lines 304, 413, and 422.

7.      Please remove dot on equation 3

8.      i [30,21], reference number must start from small to large.

9.      Line 257: the moment in which polymer enters in the mould -> cavity, mould means the whole aluminum body. Please use professional terminology for injection molding. Like runner, gate, cavity, and core. Processing parameters are not provided on injection moulding system. Like melt temperature, injection speed, and packing pressure. Those parameters are very important and they can affect the polymer property after cooling. Although you provide the references [17, 25] for injection molding, however reviewer can’t access them. Suggest putting this information on attachments.  

10.  What is the window material used in your experiments. According to my experience, sapphire glass is required otherwise glass window will be broken.

11.  References: The sequence of author’s first name and last name is not unified.

12.  Line 91: What are CDRSP, NCD-SWEET and DECTRIS?

Typos:

Line 65:  foam -> form

Line 67:  components was slower that the time scale of forming the morphology, -> grammatical error (slower?).

Line 101: 0.5s,~10nm, 2keV, 12.4keV, 1Å, 0.08mm, 6.7m, 11mm, 0.5s -> please leave a space between value and unit.

Line 251: A further complication is that as the temperature of the of the plastic cools,

Line 290: has been adjusted to maximise the the

Line 309 is please leave a space

Line 320: extrusion -> injection, extrusion and injection are two different processes.

Line 353 Wind1 Wind 1 on Figure 12, please leave a space between Wind and number

Line 403: azmuthual variation, -> azimuthal and please avoid using “we” on the technical paper.

Figure 13 and 14:  ->  Figures

Line 499: colling  -> cooling

Line 623 . Mateus, A,, A.,

Line 544: evauluation -> evaluation 

Author Response

Please see response to the reviewer comments

Author Response File: Author Response.pdf

Reviewer 2 Report

Very interesting work with promising results, however, some corrections/amendments have to be made:

1. Introduction is rather long, try to shorten it, e.g. the history of injection moulding is of minor interest for this particular publication

2. Fig. 1, in general OK, however, a schematic drawing of the experimental set up would be helpful.

3. Concerning Table 1, obviously all materials were unfilled, however, in practical utilization filled or reinforced plastic types dominate. Can you estimate up to which degree of filler/fibres you would be able to apply your charaterization methods ?

4. Provide more information about processing parameters (injection speed, shear rates etc.) which also effect material characteristics like crystallinity, orientation, residual stresses, etc.

5. Figs. 9 and 12 are hardly readable, try to magnify or place one below the other

6. Have you tried to simulate the injection and cooling steps and to correlate these data with your measurements. Do you mean this by point 6. in chapter summary ?

7. What will be the main benefits of your work for industrial polymer fabricators not having a synchrotron radiation source available ? You addressed this point only incidentally therefore it needs more discussion.

see above

Author Response

Please see attached file with responses to the comments of the reviewer

Author Response File: Author Response.pdf

Reviewer 3 Report

1. All the abbreviations should be explained upon the first appearance in the text. Now most of the abbreviations are not explained.

2. 25% of the reference list are references that are older than 23 years. Even though it is allowed to use old references in scientific publications if they are relevant to the content and provide important input to the literature review, 25% is too much, and the literature observation can be considered not actual. Therefore it is recommended to update the literature review with more recent relevant studies. For example:

https://doi.org/10.1016/j.mee.2018.03.015

https://doi.org/10.1016/j.polymer.2022.124797

etc.

3. The study is dedicated to developing the equipment that enables the evaluation of the structure and morphology development of semi-crystalline polymers during injection molding. This issue is very important as morphology directly influences the resulting polymer properties and, consequently the quality of the injection-molded parts. In this scope, it would be relevant to give a brief overview of the other methodological approaches for in-line quality control during injection molding. For example, technological parameters control with the help of in-mold sensors (https://doi.org/10.3390/s23031735; https://doi.org/10.3390/s19163551; etc.)

4. Line 49-50: “The plastic cools and becomes 49 solid after passing through a glass transition or crystallizing to form a semi-crystalline solid”. Only semi-crystalline? What about amorphous?

5. Reference to the figures should come in the text before a figure appears, not after. Please correct where necessary.

6. Figure 2. The figure needs modification with highlights of the position of in and out of X-ray beams in the mold.

7. The information about the injection molding processing parameters used in the study is missing from the Materials and Methods sections. Please, add this info.

8. The geometry of the injection molded samples is also missing from the Materials and Methods section. Needs to be added.

9. Line 309: Mistyping “σis”

10. Section names starting from Section 4 are mistyped. It shouldn’t be 4.0 and 5.0.

11. Three types of PP are examined in the study  (named PP1; PP2, and PP3).  However, the results of crystals orientation are presented only for PP1 and PP@. Why?

Author Response

Please the attached file for the responses to the comments of the reviewers

Author Response File: Author Response.pdf

Reviewer 4 Report

The technique presented in this paper is very interesting and has potential for on-line measurement of injection molded parts. 

The proposed future research, however, will not be particularly useful.  Most of the controlling parameters for injection molding are well understood - even if there are limited journal articles about these parameters.

The ability to use the new technique with a feedback loop to control the quality of injection molded parts would be of much greater interest.  The cost of the instrumentation, however, would be critical.

Overall, the paper is well written.  There are some English errors - e.g., need a space between the number and units ("1s" becomes "1 s").  

Overall, this paper is sound, but strongly suggest that the authors change the focus of what can be done with the new system.  

Author Response

Please see attached responses to the comments of the reviewers

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The authors corrected the manuscript according to the given recommendations.