Synthesis and properties of new ladder polymers with conformational flexibility and structural symmetry

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H04879
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Polymer chemistry
• Research Institution: Osaka University (2019); Tokyo Institute of Technology (2017-2018)
• Principal Investigator: Ishiwari Fumitaka 大阪大学, 工学研究科, 講師 (00635807)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: ラダーポリマー / 高分子反応 / ジアザシクロオクタン

Outline of Final Research Achievements

The synthesis of ladder polymers is still a big challenge in polymer chemistry, and in particular, there have been no reports on structurally well-defined ladder polymers with a conformationally flexible main chain. Recently, we have reported the first successful synthesis of conformationally flexible diazacyclooctane (DACO)-containing ladder polymers by a post-polymerization reaction of a rigid Troeger’s base (TB)-containing ladder polymer. The post-polymerization reaction involves sequential N-alkylation and hydrolysis for the TB base unit, resulting in a DACO skeleton that can exhibit a ring-flipping motion. The secondary amine group can readily be functionalized by various acylation or alkylation reagents. Furthermore, reversible switching of the conformational flexibility of the polymer backbone by coordination and elimination of BPh2Cl. In this presentation, we will detail the synthesis, properties and conformational switching of the DACO-containing flexible ladder polymers.

Free Research Field

高分子科学

Academic Significance and Societal Importance of the Research Achievements

高分子材料は現代の人類の生活を支える不可欠な物質であり、今後もより高機能な高分子の開発が望まれている。ラダーポリマーは、主鎖に沿って二本以上の化学結合を有するため、優れた熱安定性や力学特性ばかりでなく、制限されたコンフォメーション挙動より、通常のポリマーでは実現できない特異な物性の発現が古くから期待されている。本研究ではこれまで高分子化学分野でこれまで未開拓であった、配座柔軟性と構造対称性を併せ持つ新しいラダーポリマーを世界に先駆けて開発することに成功し、そのユニークな物性を明らかにした。