Efficient Oxygen‐Induced Molar‐Mass Control of Poly(p‐phenylene vinylenes) Synthesized via the Gilch Route
Efficient Oxygen‐Induced Molar‐Mass Control of Poly(p‐phenylene vinylenes) Synthesized via the Gilch Route
复制标题
通过 Gilch 路线合成的聚对亚苯基亚乙烯基的有效氧诱导摩尔质量控制
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
M. Rehahn
中科院分区：
文献类型：
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作者：
Thorsten Schwalm;M. Rehahn
在Gilch合成PPV的过程中，氧是一种有效的摩尔质量调节剂。作为一种清除剂，它在初始双自由基出现在体系中时立即与它们重新组合。只有当所有的氧都被使用时，才会开始形成规则的聚合物，主要是对喹诺二甲烷单体的链式聚合。由于Gilch过程中涉及的所有自由基都是双自由基，因此一些多重组事件是并行发生的。因此，最初形成的过氧二自由基也被纳入到生成的链中。后来，它们在非常温和的条件下破裂，从而导致PPV最终摩尔质量的系统性减少。
Oxygen is shown to act as an efficient molar-mass regulating agent in Gilch syntheses of PPV. As a scavenger, it undergoes instantaneous recombination with the initiating diradicals as soon as they appear in the system. Regular polymer formation can only start when all oxygen has been used, proceeding predominantly as chain-growth polymerization of the p-quinodimethane monomers. Since all radical species involved in this Gilch process are diradicals, some polyrecombination events occur in parallel. Therefore the initially formed peroxy diradicals are also incorporated into the resulting chains. Later, they break under very mild conditions, thereby causing a systematic decrease of the final molar mass of PPV.