Vol.9 No.3 2017
Research paper : A super-growth method for single-walled carbon nanotube synthesis (K. Hata)−179−Synthesiology - English edition Vol.9 No.3 (2017) per volume and time of the reaction furnace, reaction environment (vacuum system, open system, etc.), and reaction temperature. In Fig. 3, for example, if you weigh each score like excellent 4 points, good 3, moderate 2, and poor 1, the supported catalyst CVD method and fluid bed furnace method have a total of 10 points, while the super-growth method has 11 points, and there is not much difference. I think the general readers will intuitively understand the superiority of the super-growth method if you add, as items of comparison, the three items discussed in this paper: synthesis yield, reaction environment, and reaction temperature. Or, is the author’s weighing of the scores for the four items of comparison in Fig. 3 different from each point mentioned above?Answer (Kenji Hata)The four items shown in Fig. 3 show the characteristics of carbon nanotubes, and they show that the super-growth method is viable as business compared to the conventional synthesis methods. As you indicated, items such as synthesis yield per volume and time of the reaction furnace, reaction environment (vacuum system, open system, etc.), and reaction temperature are discussions about the synthesis condition. Since there are diverse synthesizing formats for each synthesis method, it is difcult to discuss the superiority or inferiority in simple terms. Also, considering practical application, I don’t think it is very meaningful to score the items of Fig. 3 as poor 1 point, moderate 2, good 3, and excellent 4.3 Safety of the single-walled CNTsComment (Toshimi Shimizu)In the rst draft, there was an expression that the researchers involved in development might quietly disregard the matter of safety of the single-walled CNTs. For the safety of single-walled CNTs, as a result of the NEDO Project, the safety test manual and guidelines for the work environment and measurements for carbon nanotubes have been published for the workers who handle the CNT materials. I recommend that you add or cite appropriate explanations and results of the concurrent R&D for the ELSI (ethical, legal, and social issues) and EHS (environmental, health, and safety) concerns that are essential in the development of nanomaterials.Answer (Kenji Hata)I corrected the text so the explanation centers on the activities conducted primarily by AIST and Zeon. At the time, the NEDO Project that led to the drafting of the safety test manual and work environment guidelines for carbon nanotubes manufactured by the super-growth method had not been implemented. Since this departs from the main topic of this paper, I did not discuss the details of the various kinds of EHS research that were conducted concurrently.Comment (Shuji Abe)In the first draft, though it may not be representative of the author’s thinking, there was a text that the readers might mistake that you are scientically negating the health damage of asbestos. I recommend you correct the text appropriately.Answer (Kenji Hata)As you indicated, I corrected the expression that may give the readers the impression that I am negating the health effect of asbestos that has been scientically proven.4 Mass production of single-walled CNTsQuestion (Shuji Abe)What specific degree of production volume do you mean when you say “mass production” in “3.1 Development of mass production technology for single-walled CNTs”? There was a description in Subchapter 2.2, that you set a personal goal of “10 tons annually,” but can I assume that the Zeon’s CNT production plant that started operation in 2015 surpassed this goal?Answer (Kenji Hata)Zeon has not released the actual gures. Therefore, I shall not publish the gures in this paper.5 Grade and quality assurance of single-walled CNTsQuestion (Toshimi Shimizu)In the case of multi-walled CNTs, I think the diameter, length, purity, metal oxide amount, specific surface area, and others are noted as their qualities. What are the parameters to assign the grade and to assure quality of the single-walled CNTs that were massively produced here? Do you conduct the quality control by using Raman spectroscopy, optical absorption spectroscopy, or thermogravimetry?Answer (Kenji Hata)In general, the carbon nanotubes synthesized by the super-growth method have the characteristics of high specific surface area, high purity, and long length, and actual quality control is done based mainly on purity and specic surface area.6 Elemental technologies of the mass production processComment (Toshimi Shimizu)You present the division of roles where AIST develops the method for solving the issues, and Zeon Corporation develops the ways to upscale the methods, continuous technology, and production technology. In “4.1 Elemental technologies of the mass production process”, can you color-categorize each elemental technology (currently grey) in Fig. 8 into those achieved by AIST, Zeon Corporation, or AIST + Zeon Corporation. In this paper, there are no names of the people in charge of the development of individual elemental technologies described in Subchapter 4.1. I think the reader’s understanding will deepen if people or organizations in charge are claried.Answer (Kenji Hata)Since this paper was written by AIST alone, I described the parts in which AIST was primarily in charge. However, to help understanding of the whole ow, I explained the parts where Zeon was in charge as much as they were disclosed. For the division of research topics between AIST and Zeon, AIST developed the fundamental technology while Zeon developed the mass production method. The research for large-area synthesis and continuous synthesis was mainly conducted by Zeon.Comment (Shuji Abe)In “4.1 Elemental technologies of the mass production process,” you describe the development of various elemental technologies, and I think you should discuss the contributions of teams and joint researchers for particularly important technologies. If it is difcult to mention them individually, it can be placed at the end in a form of acknowledgement.Answer (Kenji Hata)Since it is difcult to mention them individually, I added the acknowledgement of the people involved.7 Integration of the elemental technologiesComment (Toshimi Shimizu)The section of “4.1.7 Integration of the elemental technologies” is an overlap of the contents in 4.1.1 to 4.1.6. Here, why don’t you give us the final summary of the results of integration and the conclusion of results as much as you are allowed to disclose. I think the readers can readily understand if you refer to Fig. 8.Answer (Kenji Hata)The integration of elemental technologies is what we spent most effort on, and there are many parts that cannot be disclosed at this point, and it is very difcult to comprehensively describe the whole picture. However, it was the part on which we spent most effort, and I decided to give some details using case studies. Please understand that this paper was written under such restrictions.