Exploiting Turmeric’s Coloring Capability to Develop a Functional Pigment for Wood Paints: Sustainable Coloring Process of Polyamide 11 Powders and Their Strengthening Performance
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript needs some improves:
1. In the Abstract Section, please give a contextualization of the theme of the study.
2. Reduce the number of keywords, until five is sufficient.
3. In the Introduction Section, please insert more studies concerning relevant information about the coloring potential of turmeric powder and coloring polyamide employed as multifunctional pigments for wood coatings.
4. In the Materials and Methods Section, lines 152 -167 and Figure 2 are the text of the Results and Discussions Section.
5. In topic Characterization, insert clear text about the overall characterization techniques used.
6. In Figure 4, the respective color coordinates L*, a*, and b* can be improved to a 3D graphic including images of the samples.
7. Figure 8. (a) diagram illustrating the experimental configuration used for measuring the static friction coefficients (modified from [53]), can be added in Materials and Methods instead of in Results and Discussions.
8. The suggestion is to evaluate the CIE L*a*b* properties of the coated samples following exposure to UV-B radiation.
9. The manuscript contains numerous quantities of Figures, the suggestion is added some results as Supplementary Materials.
Author Response
- In the Abstract Section, please give a contextualization of the theme of the study.
Authors: the authors added the following sentences to line 8: “Currently, the wood coatings industry is focusing on creating unique, vibrant finishes using new functional pigments. Simultaneously, there is a growing adoption of eco-friendly bio-based materials, reflecting trends in other sectors and supporting the circular economy.”
- Reduce the number of keywords, until five is sufficient.
Authors: the number of keywords has been reduced to 5.
- In the Introduction Section, please insert more studies concerning relevant information about the coloring potential of turmeric powder and coloring polyamide employed as multifunctional pigments for wood coatings.
Authors: the authors already added some info about this topic at line 73: “Curcuminoids, which consist of curcumin, demethoxycurcumin, and bisdemethoxy-curcumin, are polyphenolic derivatives found in the rhizome. These compounds are non-toxic and exhibit a wide range of biological activities [31]. They serve as the main coloring compounds of turmeric [32,33], capable of imparting an intense yellow hue to various substances. Therefore, curcumin can effectively serve as the vibrant yellow element for applying non-toxic, bio-based organic dyes to wood coatings [34].”
Furthermore, on line 86 the authors had added: " Although the extraction and isolation of curcumin from turmeric powder were first reported in 1815 [35,36], more refined and advanced extraction techniques continue to emerge, even centuries later [37–39]. However, many of these methods often rely on the extensive use of organic solvents [40–42], which are not environmentally friendly, or employ processes with high energy consumption rates, such as pulse ultrasonic and microwave-assisted extraction methods [43–45], or temperature-based processes [44]. An alternative approach, which has been under study for a century [46], involves the synthesis of curcumin [47,48]. However, even in this scenario, the processes tend to be intricate and not particularly sustainable [35,36].”
The actual coloring power of turmeric is now known, but it is not possible in the literature to find other works that exploit this property to color polyamide 11. The novelty of the work also lies in this aspect.
- In the Materials and Methods Section, lines 152 -167 and Figure 2 are the text of the Results and Discussions Section.
Authors: the authors understand what the reviewer is referring to, but they do not agree with the request to move the text to another section. The information expressed in those lines, in addition to Figure 2, is not part of the Results, but represents a description of the method used to color the powder, and the choice of the optimal turmeric/PA11 ratio. Consequently, the authors believe it is useful to present this information in the Materials&Methods section, to explain how the colored powder, subsequently used in the production of composite coatings, was obtained.
- In topic Characterization, insert clear text about the overall characterization techniques used.
Authors: the authors added the following sentence at line 209: “Besides examining and describing the appearance of the powders and composite layers, the study thoroughly investigated how the bio-based colored filler affects the coatings' abrasion resistance, surface friction, hardness, durability, and barrier performance.”
- In Figure 4, the respective color coordinates L*, a*, and b* can be improved to a 3D graphic including images of the samples.
Authors: the authors acknowledge the reviewer's interesting advice, but had already tried this strategy, which however produced a more complex and less clear graph. Precisely for a question of clarity, the authors ultimately opted to show the appearance of the samples in Fig. 4a, and the comparison of the color bar coordinates in Fig. 4b. This allows a simpler and more immediate comparison between the 4 series of samples.
- Figure 8. (a) diagram illustrating the experimental configuration used for measuring the static friction coefficients (modified from [53]), can be added in Materials and Methods instead of in Results and Discussions.
Authors: once again the authors acknowledge the reviewer's advice: however, to limit the already high number of Figures (a problem expressed by the reviewer himself in comment 9), some images have been merged. In this case, it was chosen to present the measurement setup together with the results of the friction test, to better allow the reader to understand how the curves expressed in Fig. 8b were obtained.
- The suggestion is to evaluate the CIE L*a*b* properties of the coated samples following exposure to UV-B radiation.
Authors: this aspect was actually evaluated in lines 614-640, through colorimetric and gloss analyses, the results of which are presented in the 5 graphs of Figure 11.
- The manuscript contains numerous quantities of Figures, the suggestion is added some results as Supplementary Materials.
Authors: the authors recognize the large number of figures present in the Manuscript. However, they would prefer to keep the current images in the text, rather than move them into the Supplementary Materials. In fact, their proximity to the text allows the reader to better understand the results obtained, with greater clarity and immediacy. For this reason, the authors decided to maintain the high number of Figures in the text, grouping them according to the type of analysis carried out.
Reviewer 2 Report
Comments and Suggestions for AuthorsQuanify the word high/low, approximately, etc. as marked in the review. Measurements are done upon the argumentation of the stated words. Do not forget the statistics.
I suggest that yellow lines should be replaced with other colour, that they could gain the value for reproduction of the article.
Comments for author File: 
Comments.pdf
Author Response
Quanify the word high/low, approximately, etc. as marked in the review. Measurements are done upon the argumentation of the stated words. Do not forget the statistics.
Authors: the authors followed the several suggestions of the reviewer in the text.
I suggest that yellow lines should be replaced with other colour, that they could gain the value for reproduction of the article.
Authors: the authors followed the suggestion, changing the color of the yellow lines.
