Scholarlink

<p>In this study, diol-bridged octasilicate polymers (Diol-OSs) were synthesized via the dehydrogenative condensation reaction between octakisdimethylsiloxy octasilicate (Q<sub>8</sub><sup>DMS</sup>) and diols such as 2-butyne-1,4-diol (BYD), 1,4-benzenedimethanol (BDM), and diethylene glycol (DEG) in tetrahydrofuran (THF). The reactions were performed in the presence of <i>N,N</i>-diethylhydroxylamine, yielding the corresponding Diol-OSs: BYD-OS, BDM-OS, and DEG-OS. Correlations between the structure and physical properties of Diol-OSs were investigated. The molecular weights of Diol-OSs increased with decreasing diol:Q<sub>8</sub><sup>DMS</sup> molar ratio because side chain conversion by the diol occurred more rapidly at higher initial diol concentration. This process reduced the amount and reactivity of the remaining hydrosilyl groups, thereby decreasing the polymerization rate. Furthermore, at the same diol:Q<sub>8</sub><sup>DMS</sup> molar ratio, the molecular weight increased in the order DEG &lt; BYD &lt; BDM. This trend indicates that the chain length and rigidity of diols influence the molecular weight. Compared with DEG-OS and BDM-OS, BYD-OS exhibited a high degree of crosslinking, indicating the formation of a low-branched linear polymer with intramolecular crosslinks. Homogeneous, transparent, and flexible freestanding films of Diol-OSs were obtained by casting THF solutions of Diol-OSs into Teflon<sup>TM</sup> Petri dishes, followed by heating. Thermogravimetric-differential thermal analysis of the freestanding films revealed that the Si–O–C bonds in BYD-OS and BDM-OS decomposed more slowly than those in DEG-OS. This phenomenon can be attributed to the restricted thermal motion and stability of the rigid diol structures. The tensile strength and Young’s modulus of the BYD-OS and BDM-OS freestanding films were higher than those of the DEG-OS freestanding films because of the rigid structures of BYD-OS and BDM-OS compared with that of DEG-OS. These results demonstrate that the thermal and mechanical properties of Diol-OSs can be controlled by varying the structure of the crosslinked diol.</p><p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Diol-bridged octasilicate polymers: synthesis via dehydrogenative condensation and characterization

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年7月23日

查看全文
  • Hiroki Nonaka,
  • Ryosuke Iguchi,
  • Sota Onozato,
  • Tomohiro Imai,
  • Kazuki Yamamoto,
  • Takahiro Gunji

摘要

In this study, diol-bridged octasilicate polymers (Diol-OSs) were synthesized via the dehydrogenative condensation reaction between octakisdimethylsiloxy octasilicate (Q8DMS) and diols such as 2-butyne-1,4-diol (BYD), 1,4-benzenedimethanol (BDM), and diethylene glycol (DEG) in tetrahydrofuran (THF). The reactions were performed in the presence of N,N-diethylhydroxylamine, yielding the corresponding Diol-OSs: BYD-OS, BDM-OS, and DEG-OS. Correlations between the structure and physical properties of Diol-OSs were investigated. The molecular weights of Diol-OSs increased with decreasing diol:Q8DMS molar ratio because side chain conversion by the diol occurred more rapidly at higher initial diol concentration. This process reduced the amount and reactivity of the remaining hydrosilyl groups, thereby decreasing the polymerization rate. Furthermore, at the same diol:Q8DMS molar ratio, the molecular weight increased in the order DEG < BYD < BDM. This trend indicates that the chain length and rigidity of diols influence the molecular weight. Compared with DEG-OS and BDM-OS, BYD-OS exhibited a high degree of crosslinking, indicating the formation of a low-branched linear polymer with intramolecular crosslinks. Homogeneous, transparent, and flexible freestanding films of Diol-OSs were obtained by casting THF solutions of Diol-OSs into TeflonTM Petri dishes, followed by heating. Thermogravimetric-differential thermal analysis of the freestanding films revealed that the Si–O–C bonds in BYD-OS and BDM-OS decomposed more slowly than those in DEG-OS. This phenomenon can be attributed to the restricted thermal motion and stability of the rigid diol structures. The tensile strength and Young’s modulus of the BYD-OS and BDM-OS freestanding films were higher than those of the DEG-OS freestanding films because of the rigid structures of BYD-OS and BDM-OS compared with that of DEG-OS. These results demonstrate that the thermal and mechanical properties of Diol-OSs can be controlled by varying the structure of the crosslinked diol.