| 高分子 Vol.72 No.9 |
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特集 ソフト×高分子！
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| 展望 COVER STORY: Highlight Reviews |
| ソフトマテリアルのき裂の進展ダイナミクス Crack Growth Dynamics of Soft Materials |
Mai Thanh Tam・角田 克彦・浦山 健治 Thanh Tam MAI, Katsuhiko TSUNODA, Kenji URAYAMA |
| ＜要旨＞ き裂の進展は材料の主要な破壊形態の一つである。エラストマーに代表されるソフトマテリアルは、大変形、粘弾性、ひずみ誘起結晶化などを示すため、き裂進展は多様で興味深い特徴をもつ。近年の測定・解析技術の進歩により、超音速で進展する高速き裂についても先端近傍のひずみ分布などが特性化できるようになり、エラストマーの破壊挙動の研究は新たな局面を迎えている。 Keywords: Crack / Fracture / Elastomer / Rubber / Soft Material |
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| 計算化学によるソフトマテリアルの分子描像解明 Understanding Microscopic Dynamics of Soft Materials by Computational Chemistry |
佐藤 俊輔・渡辺 豪 Shunsuke SATO, Go WATANABE |
| ＜要旨＞ ソフトマテリアルの構造や機能の理解のために、分子レベルのダイナミクスを詳細に捉えることは非常に重要である。計算化学的手法の一つである分子動力学シミュレーションは、超分子集合体の安定性を自由エネルギーの観点から定量的に評価できる。本稿では、その概要と一例を紹介し、計算化学が超分子材料創製において果たしうる役割に触れる。 Keywords: Soft Materials / Supramolecular Assembly / Computational Chemistry / Molecular Dynamics Simulation / Free Energy Calculations / Umbrella Sampling |
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| グリーン資源由来ソフトマテリアルの展望 Prospect of Soft Materials Prepared from Green Resources |
河原 成元 Seiichi KAWAHARA |
| ＜要旨＞ 植物から得られるグリーン資源を原料とする“ものづくり”は、大気中の二酸化炭素を吸収しながらソフトマテリアルを合成することによりカーボンニュートラルの一翼を担うことが期待される。本稿では、ソフトマテリアルの中で植物によって生合成されるcis-1,4-ポリイソプレンおよび植物由来のモノマーから合成されるゴムに関して、現状を把握し、今後の展望を見据える。 Keywords: Green Resources / Natural Rubber / Guayule Rubber / Isoprene Rubber / Butadiene Rubber / Butyl Rubber / EPDM / Island-Nanomatrix Structure |
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| トピックス COVER STORY: Topics and Products |
| 二本鎖DNAによるゲルの流動性の制御 Control of Fluidity of Gels by Double-Stranded DNA |
大平 征史・LI Xiang Masashi OHIRA, Xiang LI |
| ＜要旨＞ Hydrogel, a soft material made of 3D cross-linked polymers in water, resembles biological tissue due to its high water content and viscoelastic behavior. Recent research indicates that controlling viscoelastic properties is crucial for successful medical applications. We focus on the fact that the double-stranded DNA (dsDNA) dislocation rate can be regulated by its base sequence under physiological conditions and have fabricated the new DNA gels (SP-DNA gel). SP-DNA gel is fabricated using the recently proven star polymer strategy and a pair of DNA sequences that exhibit a two-state transition as dynamic cross-linkers. The thermodynamic behavior of DNA in SP-DNA corresponds well to the simulated result, indicating that the thermo-stability of SP-DNA gels can be designed based on calculations. Furthermore, viscoelasticity measurements and dsDNA dissociation kinetics showed that the macroscopic stress relaxation time of the SP-DNA gel agreed with the dsDNA dissociation time over a wide time range, suggesting that the viscoelasticity of the hydrogel can be controlled by adjusting the dsDNA dissociation time. Keywords: Hydrogel / Visoclestisy / DNA |
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| ソフトマテリアルに寄与する可塑剤のバイオマス化 Biomass Conversion of Plasticizer Contributing to Soft Materials |
吉近 匠生 Shoki YOSHICHIKA |
| ＜要旨＞ Plasticizers are added to plastics to make them more flexible, and many of them are phthalate esters derived from petrochemicals. It is believed that if these can be replaced with plasticizers made from renewable resources, the environmental impact could be greatly reduced. In this report, we will introduce the Greencizer BZ series, a plasticizer made from renewable materials that offers equal or better performance than phthalate esters. Keywords: Circular Economy / Naturally-Derived / Plasticizer / Polyvinyl Chloride |
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| 両親水性ブロック共重合体水溶液のミクロ相分離 Microphase Separation of Double Hydrophilic Block Copolymer Aqueous Solutions |
檜垣 勇次 Yuji HIGAKI |
| ＜要旨＞ Phase separation of macromolecules in aqueous media has reignited the interest of scientists across various disciplines over the past decade. Double hydrophilic block copolymers integrating zwitterionic polymer chain exhibited unique phase separation characteristics in the aqueous solutions. The morphology transformed depending on the polymer concentration due to the interfacial curvature modulation through the volume expansion of one phase due to the selective water partitioning. The microphase separation of double hydrophilic block copolymers was also induced by cononsolvency of a zwitterionic polymer. The lyotropic mesophase of double hydrophilic block copolymers is a unique molecular compartment for hydrophilic molecules. Keywords: Microphase Separation / Block Copolymer / Zwitterionic Polymer / Water |
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| グローイングポリマー Polymer Science and I: A Personal Account |
| 社会人博士のすゝめ An Encouragement of Getting a Ph.D. while Working |
一二三 遼祐 Ryoyu HIFUMI |
| ＜要旨＞ In this column, I would like to share my experiences and difficulties in getting a Ph.D. while working full-time in a company. I hope this column will be helpful to working professionals with a master's degree who are interested in a Ph.D. degree. |
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| 高分子科学最近の進歩 Front-Line Polymer Science |
| ラジカル重合による多分岐高分子の実用的な構造制御合成法 Practical Synthesis of Structurally Controlled Dendritic Hyperbranched Polymer by Reversible Deactivation Radical Polymerization |
山子 茂・蒋 語涵 Shigeru YAMAGO, Yuhan JIANG |
| ＜要旨＞ Recent development in the synthesis of structurally controlled hyperbranched polymers (HBPs) by organotellurium-mediated radical polymerization (TERP) is introduced. Although structural control and practicality in the synthesis of HBPs have been a trade-off, we have successfully solved this issue by designing a new branch-inducing monomer called evolmer and copolymerizing it with conventional monomers under TERP. Branch numbers and density were easily controlled by changing the amount of a TERP chain transfer agent (CTA), evolmer, and conventional monomers. Furthermore, branch structures could also be controlled by using multivalent CTAs and macro-CTAs. In addition, physical properties, such as intrinsic viscosity, could also be finely tuned by the branch structure. The design principle of this method and its practical effects are discussed in this review. Keywords: Dendritimer / Hyperbranched Polymer / Highly Branched Polymers / TERP / Reversible Deactivation Radical Polymerization / Evolmer / Precision Polymer Synthesis |
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