The polymer modification by the reactive mixing using Banbury mixer was examined under various conditions. It became clear that it was necessary to add ZnO and sulfur for the reaction of Si75: [bis(3-triethoxysilylpropyl) disulfide; TESPD] with the polymer without affecting the processability. The modified polymer thus obtained showed small signal at 3.8 ppm which is attributable to TESPD moiety in ¹H-NMR analysis. The improvement of Payne effect and decrease of tanδ were observed by using the modified polymer. This technology is expected to be effective to reduce the rolling resistance of tire.

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Few reports have been published on the influence of the uniformity of rubber compounds on the quality of rubber products. In this work, NBR compounds of different degree of dispersion of additives were vulcanized in a mold equipped with two electrodes to measure the electric current during vulcanization. The electric current-cure time curves of these samples reflected the uniformity of NBR compounds.

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Biodegradable segmented poly(urethane)s (SPUs) and poly(urethane-urea)s (SPUUs) were synthesized by a standard two-step prepolymer method using two kinds of diisocyanates (methyl 2,6-diisocyanatohexanoate (LDI) and 1,4-diisocyanatobutane (BDI)) and polycaprolactone diol (PCL) as a soft segment combined with two kinds of chain extenders (1,3-propanediol (PDO) and 1,4-butanediamine (BDA)) as a hard segment. Thermal analysis by differential scanning calorimetry, wide angle X-ray diffraction (WAXD), and small angle X-ray scattering measurements revealed that different kinds of diisocyanates and chain extenders in SPUU affected the crystallinity of PCL segment and the microphase separation structure consisted of soft and hard segments. Diffraction pattern in WAXD due to the crystallization of PCL components inhibited in the cases of two SPUUs with LDI-BDA and BDI-BDA hard segments. Furthermore, these two kinds of SPUU showed good elastic properties because the crystallization of PCL component was inhibited by the strong aggregation of hard segments. The mechanical properties and degradability of poly(L-lactide) (PLLA)/SPUU blends were also investigated. A toughness of PLLA was enhanced by blending with SPUU. Also, this blend shows degradation owing to the hydrolysis. It was revealed that brittleness of PLLA was improved through blending with biodegradable SPUU without sacrificing degradability.

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Softmaterials containing magnetic particles demonstrate the change in rheological properties upon magnetic field, this is called the magnetorheology. A variety of magnetorheological materials has been investigated for the past decade. The magnetic effect on the rheological properties strongly depends on not only the types of matrix but also magnetic particles. A magnetic gel consisting of polysaccharide matrix demonstrates negative and remarkable changes in dynamic modulus upon magnetization (~10⁷ Pa). In this review, we survey the general magnetorheological effect of various softmaterials and describe the phenomenon and mechanism of the negative magnetorheological effect seen in the polysaccharide magnetic gels.

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Living radical polymerization (LRP) has been regarded as a fundamental technology for the creation of structurally well controlled polymeric materials with increased and/or new properties. This second article describes three methods of LRP, namely reversible addition-fragmentation chain transfer polymerization (RAFT), organotellurium-, stibine-, and bismuthine-mediated LRP (TERP, SBRP, BIRP), and cobalt-mediated LRP (CMRP) focusing on their methods and mechanisms. Although degenerative chain transfer mechanism plays a key role in all these three LRP methods, the differences in chemical structure of dormant species and detail chain transfer mechanisms characterize synthetic scope and limitation of each method.

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