NIPPON GOMU KYOKAISHI

Effects of Polymerization Temperature on the Structure and Properties of Thermoplastic Polyurethane Elastomers Prepared by a Prepolymer Method

Satoshi YAMASAKI, Daisuke NISHIGUCHI, Ken KOJIO, Mutsuhisa FURUKAWA

2005 Volume 78 Issue 12 Pages 447-452
Published: 2005
Released on J-STAGE: May 19, 2008

DOIhttps://doi.org/10.2324/gomu.78.447

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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 prepolymer method in bulk at various polymerization temperatures from 140 to 230°C. The molecular weight distribution of hard segment components, the glass transition temperature of soft segments, and the melting point of hard segment domains of the TPUs had very little dependence on the polymerization temperature. On the other hand, the heat of fusion and the relative proton contents of hard segment domains for the TPUs prepared above 170°C were slightly less than those for the TPU prepared at 140°C. It is conceivable that the degree of aggregation of hard segments in the TPUs became weaker with increasing polymerization temperature. The dynamic storage modulus of the rubbery plateau region and apparent shear viscosity for the TPUs prepared above 170°C were slightly less than those for the TPU prepared at 140°C. It was revealed that the aggregation structure formed at various polymerization temperatures influences not only the mechanical properties but also the melting properties of the TPUs.

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Vinyl-Type Polymerization of Cycloolefins Catalyzed by Transition Metal Complexes

Yuushou NAKAYAMA, Takeshi SHIONO

2005 Volume 78 Issue 12 Pages 453-460
Published: 2005
Released on J-STAGE: May 19, 2008

DOIhttps://doi.org/10.2324/gomu.78.453

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This review article describes vinyl addition-type polymerization of cycloolefins focusing on the polymerization of cyclopentene and norbornene. Random, block, and alternating copolymerizations of cycloolefin and other monomers are also covered.

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Polymer Blends: Principles and Applications

Part 3. Polymer-Polymer Interface and Reactive Blending

Takashi INOUE

2005 Volume 78 Issue 12 Pages 461-466
Published: 2005
Released on J-STAGE: May 19, 2008

DOIhttps://doi.org/10.2324/gomu.78.461

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Theoretical aspects of polymer-polymer interface are discussed. The interfacial thickness, the interfacial tension, and the adhesive strength are described as a function of the interaction parameter and the molecular weights of component polymers. When both component polymers have reactive sites, the coupling reaction takes place at the interface and the block or graft copolymers are formed. Melt-mixing of such reactive system is called “reactive blending” and “reactive processing”. By an emulsifying effect of the in situ-formed copolymer, the morphology could be tuned up; i.e., the size of dispersed particles can be reduced down to sub-μm to optimize the material properties. This may be a commonly accepted story for the ambiguous but convenient term “compatibilization”. Another interfacial behavior recently found is the pull-out of the in situ-formed copolymer by the external shear forces. It renders a new approach for the 10nm morphology control in reactive blending. Such interfacial aspects are successfully applied for the materials design; e.g., super-tough polyamide, high-temperature polyamide alloy for Pb-free solder, high-temperature poly(phenylene ether) alloy, and non-viscoelasic nylon alloy. The dynamic vulcanization is a unique reactive blending which leads to a two-phase material consisting of the crosslinked rubber particles and a matrix of thermoplastic polymer. Strain recovery mechanism of the two-phase material is discussed.

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Development of High Performance Elastomers with Inorganic Filler

5. Effects of Inorganic Fillers on Environmental Degradation of Vulcanizates and Mechanical Properties of Thermoplastic Elastomers, and Inorganic Fillers in the Future

Soji KODAMA

2005 Volume 78 Issue 12 Pages 467-474
Published: 2005
Released on J-STAGE: May 19, 2008

DOIhttps://doi.org/10.2324/gomu.78.467

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This paper referred to the effects of inorganic fillers on photo and heat aging of vulcanizates and the mechanical properties of thermoplastic elastomers. The photo aging resistance of vulcanizates filled with a plate-like filler such as kaolin clay was superior to that of vulcanizates filled with a granular-like filler such as silica and calcium carbonate. It was due to low permeability for both light and oxygen of vulcanizates filled with a plate-like filler. On the other hand, in the case of heat aging, vulcanizates filled with silica showed better resistance than those filled with carbon black in the presence of antioxidants. It seemed that an acidic filler such as silica activated antioxidants by acid-base interaction between a hydroxyl group on filler surface and an antioxidant. Some references of the effect of inorganic fillers on the physical properties of thermoplastic elastomers were reviewed. Several topics of inorganic fillers in the future were also referred.

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[title in Japanese]

[in Japanese]

2005 Volume 78 Issue 12 Pages 475-476
Published: 2005
Released on J-STAGE: May 19, 2008

DOIhttps://doi.org/10.2324/gomu.78.475

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