Two kinds of vanadium catalyst were prepared by the reaction of VOCl₃, ROH(R=CH(CH₃)C(CH₃)₃, CH₂C(CH₃)₃) and AlⁱBu₃. Both catalysts were able to produce alternating copolymer of 1,3-butadiene and propylene (PBR). The spectroscopic structures of obtained copolymers appeared to be almost the same, but the thermal properties of them were different from each other. The copolymer produced by the catalyst having a chiral carbon showed a melting point at 5 °C, which was not observed in the copolymer by other catalyst. This result indicates that the stereoregularity was dramatically improved by the catalyst with a chiral carbon in alternating copolymerization of butadiene and propylene.

To improve computation efficiency of Molecular dynamics (MD) method dramatically, we developed Renormalized molecular dynamics (RMD) method. This method makes it possible to decrease the number of particles whilst maintaining macroscopic phenomena at similarity. We carried out polymer simulation by using RMD method and have succeeded in replicating several particular phenomena of viscoelastic fluids.

Protein-free natural rubber was prepared by incubation of high ammonia natural rubber latex with urea, sodium dodecyl sulfate and polar solvent at room temperature followed by centrifugation. Total nitrogen content and extractable protein content of natural rubber were reduced from about 0.4 w/w% and 100 μg/ml to 0.00 w/w% and 0.0 μg/ml, respectively, after removing all proteins from the rubber. Nanophase separated structure of natural rubber, in which natural rubber particles with a diameter of about 1 μm were dispersed in matrix of non-rubber components with a thickness of several tens nm, disappeared when the proteins were completely removed from the rubber. Stress at break of unvulcanized natural rubber was significantly larger than unvulcanized protein free natural rubber, while it was identical to unvulcanized DPNR. Water-uptake was dependent upon total nitrogen content and it was lowest for protein free natural rubber. The vulcanization time of natural rubber was prolonged by removing proteins and tensile properties of the vulcanized protein free natural rubber were better than natural rubber after immersing into ethylene glycol solution. It is found that the protein free natural rubber is a novel, superior rubber, which is distinguished from natural rubber.

Internal mixers are widely used in rubber compounding in tire manufacturing process. This paper is a review of rubber mixing analysis in internal mixers and consists of two parts. First one is a literature review of rubber mixing simulation in internal mixers. Literatures were summarized in four view points; fully-filled simulation, partially-filled simulation, evaluation method and comparison with experimental results. Second part shows the examples of the authors' partially-filled mixing simulation and its visualization results by using expanded coordinate and particles as fluid.

Some of the important concepts and experimental results for the studies on polymer based composite materials are presented.

1) For short fiber reinforcement, the most important factors are the aspect ratio and the ratio of the Young's modulus of the fiber and the matrix. Concept of the effectiveness of short fiber reinforcement is presented depending on the aspect ratio and the ratio of the modulus. The next is the degree of orientation of the short fiber and it is shown with real examples.

2) For the real composite materials, three dimensional shape of the reinforcing materials is important and some examples observed by three dimensional transmission electron microscope are presented.

3) Role of the interface in composite materials is pointed out with experimental results based on nano-mechanical mapping as well as the polymer surface.

4) Studies of the composite materials under deformation are emphasized for the practical application with some examples. Finally, expectation of polymer based composite materials supported by polymer nanotechnology is presented with very recent national project.