Sulfur-crosslinked EPDMs were examined by ¹H pulsed NMR. Spin-spin relaxation time (T₂) was measured by Hahn echo method. The decay curve was resolved into two components, T_2n and T_2nn, which were arising from network molecules and non-network molecules, respectively. For unfilled EPDMs prepared at varying sulfur content, the higher order structures analyzed by Hahn echo method were almost the same as those analyzed for peroxide-crosslinked EPDMs. The reciprocal of Ten measured at 150°C for unfilled EPDMs increased linearly with increase in apparent crosslinking density (ν_s) values determined by modified Flory-Rehner equation. For EPDMs filled with carbon black (CB), the crosslinking density of rubber phase (ν_R) was calculated from the relationship between ν_s and 1/T_2n for unfilled EPDMs. The crosslinking density related to CB (ν_F) was obtained from the difference between the ν_s and ν_R. The ν_F values showed good correlation with the tensile stress at 100% elongation, independent of the kinds of cure agents.

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Effects of polymerization temperature on the molecular aggregation structure and the mechanical and melting properties of thermoplastic polyurethane elastomers (TPUs) were investigated. The TPUs were prepared from poly(ethylene adipate)glycol, 4, 4'-diphenylmethane diisocyanate, and 1, 4-butanediol by a one-shot method in bulk at various polymerization temperatures from 140 to 230°C. Glass transition temperature of the soft segment and melting point of the hard segment increased and decreased with increasing polymerization temperature, respectively. The pulsed NMR analyses of the TPUs indicated that the relative proton contents in the interfacial phase between hard and soft phases and its spin-spin relaxation time increased with increasing polymerization temperature. It is conceivable that the degree of microphase-separation of the TPUs became weaker with increasing polymerization temperature. Dynamic storage modulus for the rubbery plateau region of the TPUs prepared at 140 and 170°C were much higher than those at 190 and 230°C. Also, viscosity measurement revealed that the TPUs prepared at lower polymerization temperature bare the non-Newtonian behavior for wide shear rate region owing to the residual hard segment domains at an operated temperature. These results can be attributed to the degree of microphase-separation and melting temperature of the hard segment domain in the TPUs.

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Chemical admixtures have been widely used for the purpose of a functional investment to cement concrete materials, and a large quantity of polymeric surfactants have been used as the component in chemical admixtures.
In recent years, a chemical admixture, namely high-range AE water-reducing agent (HRWR) comprising from water-soluble graft copolymer have played an important role to the promotion of ultra high strength concrete for super high-rise RC structure.
Therefore, this report relates especially to the role of HRWR for ultra high strength concrete. First of all in this articles, the fundamental principles and common properties to get the high strength of cementitious materials were explained, and continually the chemical structures of HRWR, cement dispersing mechanism and the application of ultra high strength concrete were reviewed.

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This paper referred to the reinforcement effect of inorganic fillers on mechanical properties of vulcanizates of non self-reinforcement rubber such as SBR. Tensile strength (T_B) abruptly became higher with the increase of specific surface area of fillers, whereas tensile modulus was not improved. he increase of T_B can be explained by the physical interaction between filler surface and rubber matrix, because the surface energy of filler increases with the decrease the particle size. On the other hand, the chemical interaction is responsible for tensile modulus improvement. Some methods to improve chemical interaction were also discussed.

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