| 高分子 Vol.65 No.5 |
| >> Japanese | >> English |
特集 ものづくりはここから：ゴム状態の科学
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| 展望 COVER STORY: Highlight Reviews |
| 高分子網目系ソフトマテリアルの大変形挙動の解析 Large Deformation Behavior of Polymer-Network Based Soft Materials |
浦山 健治 Kenji URAYAMA |
| ＜要旨＞ ゲルやゴムなどの高弾性を示す物質は架橋されたゴム状態の三次元高分子網目である。均一な網目構造のゲル、網目鎖に沿った可動性の架橋点をもつゲル、多孔質ゴムの大変形挙動を二軸伸長測定によって調べた最近の研究を解説する。ゴムのき裂の進展速度の転移現象をき裂先端の形状の追跡から調べる研究も紹介する。
Keywords: Elastomers / Rubber / Gels / Foams / Elasticity / Fracture / Polymer Networks |
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| ゴム－ガラス転移のレオロジー Rheology of Rubber on Glass Transition |
宮本 嘉久 Yoshihisa MIYAMOTO |
| ＜要旨＞ ゴムに変形を与えると、温度・変形速度に応じて、ゴム弾性、結晶化、粘弾性、塑性変形、破壊と多様な変形様式を示す。本稿では、ゴム－ガラス転移における大変形一軸伸長下での線形粘弾性の温度・歪依存性と、ガラス転移領域での応力－歪関係と応力緩和についての解析結果を紹介する。 Keywords: Rubber / Glass Transition / Linear Viscoelasticity / Strain Dependence / Stress-Strain Curve / Stress Relaxation |
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| フィラー充填ゴムの階層的網目構造 Hierarchical Network Structures in Filled Rubbers |
五十野 善信 Yoshinobu ISONO |
| ＜要旨＞ フィラー充填ゴムはガラス転移温度の低い高分子とカーボンブラックやシリカのような無機充填剤の混合物である。その高弾性・高強度は高分子／高分子、高分子／フィラー、フィラー／フィラー間相互作用による階層的網目構造に由来する。フィラー充填ゴムの顕著な非線形粘弾性はこれらの網目構造変化による。 Keywords: Rubber / Filler / Crosslink / Hierarchical Networks / Inhomogeneity / Nonlinear Viscoelasticity / Entropy Elasticity / Energy Elasticity |
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| トピックス COVER STORY: Topics and Products |
| 天然ゴムの伸長結晶化における新概念 New Concept in Strain-Induced Crystallization of Natural Rubber |
登阪 雅聡 Masatoshi TOSAKA |
| ＜要旨＞ Despite the long history of studies, a quantitative theory on strain-induced crystallization of natural rubber has not been fully established. All the theories so far have considered the entropy change due to extension as the only factor to enhance crystallization. We obtained experimental data about the dependence of crystallization rate on stretch ratio. The results were compared with theoretical calculations based on the previous concept regarding the entropy change as the only factor. However, the theoretical calculations were totally inconsistent with the experimental results. The origin of this discrepancy was found to be the calculated high activation energy of nucleation even after the entropy change due to extension was considered. This quantitative comparison indicated that the reduced surface free energy due to the formation of bundle-like nuclei is the additional factor to enhance crystallization. Furthermore, it was revealed that surface energies have a greater effect on the decrease of the activation energy than the entropy change by extension. Keywords: Nucleation / Crystallization Rate / Rubber Elasticity / Surface Free Energy / Crystallite Size / Stretch Ratio |
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| ゴム材料開発のための粗視化シミュレーション技術 Coase-Grained Simulations for the Development of Rubber Materials |
森田 裕史 Hiroshi MORITA |
| ＜要旨＞ The simulation studies of the rubber materials using coarse-grained simulations are described. In these studies, we focus on the analysis of rubber materials. The coarse-grained molecular dynamics method is applied to simulate the elongated structure of rubber materials. In the elongated structure, the expanded bonds can be analyzed, and the bond-lines, which is the origin of the stress of elongated rubber, can be obtained in our analysis. Using self consistent field simulation, the end segment distributions in the filler filled materials are estimated. From our simulations, the segregation of the end segment at the interface of filler can be found. The information derived from the coarse-grained simulations will be important to develop the next generation of rubber materials, and in the near future, further analysis techniques to analyze the rubber materials will be developed. Keywords: Coarse-Grained Simulation / OCTA / MD / SCF |
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| 加硫天然ゴムの架橋点の構造と物性 Tructure of Crosslinking Junctions and Properties of Vulcanized Natural Rubber |
河原 成元 Seiichi KAWAHARA |
| ＜要旨＞ Crosslinking junction as a constituent may play an important role in mechanical properties of rubbers and gels. This may be analyzed by field gradient-fast-magic angle spinning (FG-FMAS) NMR spectroscopy, which is developed to eliminate effect of dipole-dipole interaction for the rubbers and gels. The FG-FMAS NMR spectroscopy enabled to apply various pulse sequences such as DEPT, APT, HETCOR, HMQC, HSQC and HMBC to the vulcanized natural rubber; so that, it makes possible to determine the structure, positively. Here, a structural analysis of the crosslinking junctions of vulcanized natural rubber is described in terms of not only 1D-NMR method but also 2D-NMR method. The structure of crosslinking junctions is found to be dependent upon accelerator. The outstanding mechanical properties of vulcanized natural rubber are related to the structure of the crosslinking junctions. Keywords: Natural Rubber / Vulcanization / Crosslinking Junction / Solid State NMR / Field Gradient-Magic Angle Spinning / 2D-Measurement / Stress-Strain Curve / Tensile Strength |
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| グローイングポリマー Polymer Science and I: A Personal Account |
| 海外研究で感じたこと My Experience of Working Abroad |
河野 慎一郎 Shinichiro KAWANO |
| ＜要旨＞ After working as a postdoctoral fellow at the Max Planck Institute for Polymer Research in Mainz, Germany, I have learned about the importance of not only doing presentations in English but also making fruitful connections with researchers of very different backgrounds. This short article describes what I experienced and how I struggled abroad. |
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| 高分子科学最近の進歩 Front-Line Polymer Science |
| ポリウレタンの科学 Current Polyurethane Science |
小椎尾 謙 Ken KOJIO |
| ＜要旨＞ Polyurethane studies has been still fascinating to us. In this review, current polyurethane science has been addressed focusing on structure-properties relationship of polyurethane with controlled primary strcutre, structure analysis using synchrotron radiation x-ray diffraction and scattering, development of polyurethane withself-healing properties, environment friendly polyurethanes. It is expected that polyurethane would give new brand properties by studies combining analysis based on synchrotron radiation x-ray and simulation. Keywords: Polyurethane / Primary Structure / Synchrotron Radiation X-ray / Self-Healing / Environmental Friendly / Elastomer |
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