This award will support a six-month research effort at Kyoto University in Japan by Dr. Charles C. Han, Polymer Division, National Institute of Standards and Technology (NIST). Dr. Han's host at Kyoto University will be Professor Takeji Hashimoto, of the Department of Polymer Chemistry. The scientists are collaborating on a study of rubber/rubber blends. Well characterized deuterated polybutadiene/protonated polybutadiene and deuterated polybutadiene/protonated polyisoprene blends will be studied, using the technique of small angle neutron scattering (SANS) to obtain detailed structural and conformational information on these polymers. The blends serve as ideal systems to investigate the fundamentals of phase behavior of binary systems. The effects of chemical crosslinking on phase behavior of these polymer blends will also be studied. At Kyoto University Dr. Han will participate in the synthesis, microstructure characterization, and specimen preparation of the various blends. The SANS measurements will be carried out later at NIST by Dr. Han and visiting members of the Kyoto group. While in Japan Dr. Han will also make brief visits to other academic and industrial research groups working in this field. Polybutadiene blends, polyisoprene blends, and polybutadiene/ polyisoprene blends of various microstructures are widely used in the rubber and tire industries. The blends are tailored to achieve various desired properties in the final products. The studies to be carried out in this collaboration may be expected to lead to a greater predictivity of the phase diagrams of rubber/rubber blends, and to other contributions to the technology base for the rubber industry.
