Surpa impact resistance of the new rubber material
Thermoplastic elastomers (TPE – sometimes referred to as thermoplastic rubbers) are a chemically bonded combination of several polymers (“copolymers”) – usually a plastic and a rubber – that have both thermoplastic and elastomeric properties. The thermoplastic property is useful in injection molding, while the elastomeric property gives the object the ability to stretch and almost return to its original shape. These materials are ubiquitous, for example, inside and outside of vehicles. The most well-known TPEs are “styrenic block polymers”, which contain molecular blocks of polystyrene, which is hard, and polydiene, which is rubbery. Two prominent examples are polystyrene-b-polyisoprene-b-polystyrene (SIS) and polystyrene-b-polybutadiene-b-polystyrene (SBS). Styrenic block polymers were developed by the Shell Chemical Company in the 1960s and have since been perfected by many researchers in academia and industry. While the annual global market for TPEs based on styrenic polymers is in the billions of dollars, elastomers with improved mechanical properties, especially toughness, also remain in high demand.
To improve the mechanical properties of styrenic block polymers, Nagoya University and Zeon Corporation recently reported an industry-friendly synthesis of chemically modified SISs such as hydrogen bonded SIS (h-SIS) and “SIS to. ionic function ”(i-SIS) – which is SIS with positive ions such as sodium bound in it. The “cation” has an electron (monovalent) removed from the outer shell. (See https://doi.org/10.1016/j.polymer.2021.123419.) Preliminary measurements have shown that the i-SIS has an extremely high tensile strength of 480 MJ / m3, which is the highest value of any thermoplastic rubber material known to our knowledge.
Although a preliminary tensile test is useful for studying the common mechanical properties of materials, it does not reveal all the mechanical characteristics of materials, especially impact resistance which is of critical importance in practical applications. Additionally, measuring impact resistance is also important in understanding the mechanism by which desirable mechanical properties arise in the material, and hence how they can be achieved.
This study by Nagoya University and Zeon Corporation is the first to assess the impact resistance of new i-SIS-based elastomeric materials and compare them to the impact resistance of a typical high-strength material. made from glass fiber reinforced plastic. (GFRP), which has a tensile strength of 330 MPa. Impact resistance tests have shown that i-SIS with monovalent or divalent cations is 3-4 times more impact resistant than chemically unmodified SIS; in addition, i-SIS with divalent cations is found to be 1.2 times more impact resistant than typical high strength GFRP. All in all, i-SIS, especially with the divalent ions, has been shown to be very impact resistant, although inorganic fillers – a typical additive for polymer curing – are not incorporated into the polymer and the molecular structure of the polymer is not chemically crossed. bound.
Automakers and other automakers are constantly on the lookout for materials that are lighter and more resistant to damage. Since i-SIS can be synthesized on an industrial scale, it has great potential to become a next-generation elastomeric material for use not only in interior and exterior automotive parts, but also in automotive bodies, and even the exterior panels of automobiles, trains and other vehicles which require structural materials with high impact resistance as well as ease of manufacture. These research achievements will also contribute to the development of light vehicles and the establishment of a carbon-free society.
The paper, “Thermoplastic elastomers based on highly impact resistant block polymers with an ionically functionalized rubber phase” was published in ACS Omega on December 20, 2021, at https://doi.org/10.1021/acsomega.1c05609 (OPEN ACCESS).
Authors: Takato Kajita1, Atsushi Noro1.2*, Ryoji Oda3, and Sadaharu Hashimoto3
1 Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University
2 Institute of Materials Innovation, Institutes of Innovation for Future Society, Nagoya University
3 Zeon Corporation, 1-6-2 Marunouchi, Chiyoda-ku, Tokyo 100-8246, Japan
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About Nagoya University, Japan
Nagoya University has a history of around 150 years, with its roots in a temporary medical school and hospital established in 1871, and was officially established as the last imperial university in Japan in 1939. Although large modest compared to the largest universities in Japan, Nagoya University has pursued excellence since its founding. Four of the 18 Japanese Nobel Laureates since 2000 have done all or part of their work at Nagoya University – 2014 Nobel Laureates in Physics Isamu Akasaki and Hiroshi Amano; and Nobel laureates in chemistry Ryoji Noyori (2001) and Osamu Shimomura (2008). In addition, two Nobel Laureates – Toshihide Maskawa and Makoto Kobayashi – 2008 Physics Prize winners – graduated from Nagoya University (one with a doctorate from Professor Sakata, who was highly regarded by eminent physicists such than Murray Gell-Mann) then went to the Yukawa Institute in Kyoto, and then returned to Nagoya University to head the KMI research institute. Shigefumi Mori did her job earning her the Fields Medal at Nagoya University. In 2000, Kimio Niwa played a leading role in the DONUT experiment conducted at Fermilab, in which the tau neutrino was observed for the first time, inventing the Emulsion cloud chamber which made observation possible, and which has since been adapted to detect other particles. A number of other important discoveries were also made at the university, including the Okazaki DNA fragments by Reiji and Tsuneko Okazaki in the 1960s; and the forces of exhaustion by Sho Asakura and Fumio Oosawa in 1954.
The title of the article
Highly impact resistant block polymer-based thermoplastic elastomers with ionically functionalized rubber phase
Publication date of the article
The authors declare the following competing financial interest (s): 1. Patent applicant: Nagoya University; Name of the inventors: Atsushi Noro, Mikihiro Hayashi, Ryusuke Hiramatsu, Yushu Matsushita; Application Number: JP2014-227272; Title: Non-covalent bonded elastomer. 2. Patent applicant: Nagoya University; Name of the inventors: Atsushi Noro, Maho Ohno; Application number: PCT / JP2016 / 063152; Title: Flexible elastomer with non-covalent bond and its manufacturing process; 3. Patent Applicant: Zeon Corporation, Nagoya University; Name of the inventors: Kosuke Isobe, Sadaharu Hashimoto, Atsushi Nozawa, Ryoji Kameyama, Atsushi Noro, Takato Kajita, Yushu Matsushita; Application number: PCT / JP2018 / 017439; Title: Block copolymer composition obtained by modification treatment, method of producing same, modified block copolymer composition used therefor, and method of producing said modified block copolymer composition; 4. Patent Applicant: Zeon Corporation, Nagoya University; Name of the inventors: Kosuke Isobe, Sadaharu Hashimoto, Atsushi Nozawa, Atsushi Noro, Takato Kajita, Yushu Matsushita; Application number: PCT / JP2018 / 031200; Title: Multiblock copolymer composition obtained by modification treatment, and film. 5. Patent Applicant: Zeon Corporation, Nagoya University; Name of the inventors: Kosuke Isobe, Sadaharu Hashimoto, Atsushi Noro, Takato Kajita, Haruka Tanaka, Yushu Matsushita; Application number: PCT / JP2019 / 017675; Title: A block copolymer composition having an ionic group and a film.
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