Crystalline-State Polymerization of Diethyl (Z,Z)-2,4-Hexadienedioate via a Radical Chain Reaction Mechanism To Yield an Ultrahigh-Molecular-Weight and Stereoregular Polymer
Crystalline-State Polymerization of Diethyl (Z,Z)-2,4-Hexadienedioate via a Radical Chain Reaction Mechanism To Yield an Ultrahigh-Molecular-Weight and Stereoregular Polymer
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通过自由基链反应机制进行 (Z,Z)-2,4-己二烯二酸二乙酯的晶态聚合以产生超高分子量和立构聚合物
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发表时间：
1998
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通讯作者：
Masamichi Kobayashi
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作者：
A. Matsumoto;Katsutaka Yokoi;S. Aoki;K. Tashiro;and Toshiya Kamae;Masamichi Kobayashi
我们研究了结晶态(Z,Z)-2,4-己二烯二酸二乙酯(EMU)在紫外线照射下自由基聚合产生具有高度调控立体化学结构的超高分子量聚合物的反应机理。通过凝胶渗透色谱和粘度测定，无论聚合温度如何，聚（EMU）的分子量估计远高于 106，而聚合速率则显着依赖于温度。聚合过程中通过 X 射线衍射监测的晶体结构变化证明了产生聚 (EMU) 晶体的晶体间反应过程。 X射线衍射和核磁共振波谱的结果证实，增长是在晶格控制下进行的，导致内消旋二全同立构反式2,5-聚合物成为完全调控的结构。 ESR 测量揭示了自由基链机制以及长寿命传播链的形成...
We have investigated the reaction mechanism of the radical polymerization of diethyl (Z,Z)-2,4-hexadienedioate (EMU) in the crystalline state under UV irradiation to yield a polymer of ultrahigh molecular weight with a highly regulated stereochemical structure. The molecular weight of poly(EMU) was estimated to be much higher than 106 by gel permeation chromatography and viscometry, irrespective of the polymerization temperature, in contrast to the polymerization rate, which significantly depended on the temperature. The crystal structural change monitored by X-ray diffraction during the polymerization has evidenced the crystal-to-crystal reaction process yielding the poly(EMU) crystals. The results of X-ray diffraction and NMR spectroscopy confirmed that the propagation proceeded under a crystal-lattice control, leading to the meso-diisotactic-trans-2,5-polymer as a completely regulated structure. The ESR measurement has revealed the radical chain mechanism and the formation of a long-lived propagating r...