Rubber Division, ACS reserves the right to make changes to this program pending Steering Committee review, presentation time changes, speaker cancellations, etc.
Rubber Division, ACS 199th Technical Meeting
April 27-29, 2021; Independence, OH
Featured topics for this meeting:
Elastomers as Biomaterials
Modeling & Simulation
Structure and Dynamics of Polymer Nanocomposites and Filled Rubber
Failure of Rubber Materials
Science of Rubber Additives
Advances in Rubber Processing
Science & Technology Award Winner Presentations
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Tuesday, April 27; 9:00 a.m. - 10:00 p.m.
Seiichi Kawahara - Professor, Department of Materials Science and Technology, Nagaoka University of Technology
An expert on natural rubber science and technology, Professor Seiichi Kawahara has spent the last three decades investigating a relationship between structure and properties of natural rubber. He also has a strong interest in control of hierarchical structure of rubbery materials. After receiving his doctorate in Engineering from Tokyo University of Agriculture and Technology in 1992, Kawahara began his career as assistant professor at Tokyo University of Agriculture and Technology. He made collaborative research works with Prof. Yasuyuki Tanaka. He joined rubber research group of Prof. Alan Gent and Prof. Gray Hamed at Akron University in 1996-1997 as a visiting scientist. After coming back from USA, he was promoted to Associate Professor of Nagaoka University of Technology. Currently, he is professor of Nagaoka University of Technology. Kawahara has served on advisory boards for Polymers for Advanced Technology and Journal of Rubber Research. He published 220 peer-reviewed papers and 29 patents. He received 12 awards from societies: for instance, the Science and Technology Award in 2015 from the Society of Rubber Science and Technology, Japan, the Sparks-Thomas Award in 2014 from the American Chemical Society, USA, the SPSJ Wiley Award in 2011 from the Society of Polymer Science, Japan, the SRJ Research Award in 2004 from the Society of Rheology, Japan.
Development of Sustainable Natural Rubber Ecosystem Toward Creation of New Industry
"Natural rubber ecosystem” has a potential to contribute to the establishment of a sustainable society as an important elementary component. It achieves a direct capture of carbon dioxide, CO2, from the air since natural rubber is a secondary metabolite biosynthesized by thousands of plants such as guayule in the desert, Russian-dandelion in the steppe, Hevea brasiliensis in the tropical rainforest and so forth. Various products useful for human lives may be produced from natural rubber. In other words, the natural rubber ecosystem is a global carbon cycle that continuously uses natural rubber as a source to prepare many products useful for human beings who co-exist and co-prosper with the plants growing in every country and region on the earth planet. This may lead to greening of the desert and creation of a favorable environment for plant growth; so that, the plants grow thick and forests expand. As the forests expand, a direct capture of greenhouse gases (GHG), i.e., CO2, may increase. The natural rubber ecosystem begins with purifying and drying natural rubber. Products are manufactured by reacting and mixing with various ingredients with purified natural rubber and dried natural rubber and precisely controlling their nanostructures. After using the products, valuable low molecular weight compounds are produced as the ingredients by biodegradation of the used products. The ingredients, used several times, may be completely biodegraded to CO2 that is released to the air. The released CO2 is directly captured by the plants to produce natural rubber, again. This may result in the global carbon cycle with natural rubber, i.e., natural rubber ecosystem, based on natural rubber chemistry instead of petroleum chemistry. We have spent 30 years or more to establish the natural rubber chemistry as an eco-friendly chemistry. First, we have carefully analyzed hierarchical structure of natural rubber since it is a multicomponent system consisting of cis-1,4-polyisoprene as a rubber hydrocarbon and non-rubber components such as proteins, lipids, carbohydrates and so forth. We discovered a nano-phase separated structure, i.e., nanomatrix structure, which was composed of natural rubber particles with an average diameter of about 1 mm as a dispersoid and nanomatrix of non-rubber components such as proteins and phospholipids with a thickness of several tens nm as a matrix. The non-rubber components were chemically and physically attracted with the terminal groups of cis-1,4-polyisoprene. Based on this discovery, we completely removed proteins and lipids from natural rubber. Protein-free natural rubber was invented as the purest natural rubber containing 0.00 w/w% nitrogen source. Secondly, we have studied preparations of various polymers from protein-free natural rubber. For instance, organic materials with an organic-inorganic nanomatrix structure were prepared by replacing the proteins to inorganic nanoparticles. In addition, hydroxyl group-containing natural rubber, epoxidized natural rubber, cyclic carbonated natural rubber, hydrogenated natural rubber and phenyl group-containing natural rubber were prepared from protein-free natural rubber by reacting with oxygen, carbon dioxide, water, hydrogen and cinnamic acid-based monomers. Currently, more reactions are explored to increase product lineup, aiming to establish the “natural rubber chemistry”. An overview of the natural rubber ecosystem is addressed in this lecture. Preparation of protein-free natural rubber based on the structure of the rubber, construction of purification plant for natural rubber latex, production of dryer for protein-free natural rubber latex and preparation of various polymers from protein-free natural rubber are introduced as a part of natural rubber chemistry.