Effects of dimethylglyoxime and diacetyl monoxime on the vulcanizing behavior of SBR and NBR are investigated. When the oxime compounds were used in the presence of 0.2 phr of zinc oxide as an accelerator activator, the vulcanization proceeded at faster cure rate and reached to the higher maximum torque compared to those obtained in the absence of oxime compounds. Furthermore, the scorch time was recognized to be nearly equal or slower. The mechanical properties of the rubber vulcanized with oxime compounds together with 0.2 phr of zinc oxide and its aged samples were shown to be the almost same level with those vulcanized with 2 phr of zinc oxide in the absence of oxime compounds. Therefore, using oxime compounds made it possible to reduce the amount of zinc oxide until about 0.2 phr without loss of performance of the vulcanized rubber, which is about one tenth of usually used amount in vulcanization process, e.g. 2 phr.

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This paper describes the roles of tip-clearance zone between rotortip and chamber wall in internal mixers.
It would be considered that there will be the grinding and dispersion of filler agglomerate or polymer and the removing of heat from the mixers in the tip-clearance zone, the greatest shear zone, mainly.
Rubber mixing processes in the industry scale mixers will be extremely influenced by the heat generated in the tip-clearance zone. There will be the heat removal difficulties by decrease of cooling area with increase of mixer size. The size of tip-clearance and the width of the rotortip of large mixers will be of great importance for these processes.

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Hyperbranched polymers have received considerable attention in recent years due to their unusual properties arising from their unique molecular architecture and convenient synthesis by one-step polymerization of AB_m (m ≥ 2) type monomers. However, hyperbranched polymers obtained by general synthetic methods have two disadvantages. First, the branching structure is not perfect; polymer topology is not well controlled. Second, the molecular weight is also not well controlled, and the molecular weight distribution is broad. These defects stem from the fact that the AB_m monomers are generally polymerized by polycondensation or polyaddition, which proceeds through a step-growth polymerization mechanism. Herein we describe a new approach to controlled polymerization of AB₂ monomer from a core molecule in a chain-growth polymerization manner by using the change of substituent effects between the monomer and the polymer. Furthermore, properties of the obtained hyperbranched polyamides, synthesis and self-assembly of well-defined polystyrene-b-hyperbranched polyamides were also investigated.

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The origins and activities of haigoshi, or alchemistic compounding specialists are reviewed in relation to the Japanese rubber industry at Meiji and Taisho periods.

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