Depolymerization/functionalization of silicones in mild conditions: A “Back-to-polymers” strategy to turn wastes into up-cycled polymers

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2025-03-29 DOI:10.1016/j.polymdegradstab.2025.111343

Antoine Forens , Aurélie Boulègue-Mondière , Fabien Dupin , Nicolas Durand , Daniel Portinha , Etienne Fleury

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引用次数: 0

Abstract

Silicones based on polydimethylsiloxanes are widely-spread materials owing to their exceptional mechanical, thermal and chemical properties and biocompatibility, among other characteristics. As for any other man-made plastics, recycling silicone-based materials appears essential to transition to a more sustainable production model, lowering the amount of waste that is then turned into valuable building blocks. While conventional processes of chemical recycling of silicones generally describe the recovery of cyclic organosiloxane monomers, herein we introduce an efficient and robust method that produces polymers instead with limited amount of produced cycles (<2 wt%). It relies on reactions carried out at room temperature that use 4-dodecylbenzene sulfonic acid combined with dialkysiloxanes as chain transfer agents. When starting from a polydimethylsiloxane oil, linear polymer chains are obtained with molecular weight lower than the one of the initial substrates, that can be tuned by both the acid and dialkysiloxane contents. A variety of end-cappers (molecular, oligomeric or polymeric; non-functionalized or functionalized with Si-vinyl or Si-H groups) were successfully used, and a mechanism in agreement with the experimental results is suggested. Our method not only applied on silicone oils but also on filler-free crosslinked polymers and some manufactured silicone elastomers. It is shown that when functionalized with either Si-vinyl or Si-H groups, the so-called “recycled” polymers can act as reactive precursors for the preparation of novel silicone elastomer by hydrosilylation reaction. An example of an elastomer made from 100 % recycled silicones is presented. Therefore, our approach represents a robust way to obtain reactive silicone precursors by “upgrading” initially inert oils or by “upcycling” products originally intended to scrap, and in this sense can contribute to enriching circular models for silicone materials.

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温和条件下有机硅的解聚/功能化：将废物转化为上循环聚合物的“回归聚合物”策略

基于聚二甲基硅氧烷的有机硅由于其优异的机械、热、化学性能和生物相容性等特性而成为广泛应用的材料。至于其他人造塑料，回收硅基材料似乎是向更可持续的生产模式过渡的关键，减少了转化为有价值的建筑材料的废物量。虽然传统的有机硅化学回收工艺通常描述的是循环有机硅氧烷单体的回收，但在这里，我们介绍了一种高效而稳健的方法，以有限的生产周期（<2 wt%）生产聚合物。它依赖于使用4-十二烷基苯磺酸与二烷基硅氧烷作为链转移剂在室温下进行的反应。当从聚二甲基硅氧烷油开始时，得到的线性聚合物链的分子量比初始底物的分子量低，可以通过酸和二烷基硅氧烷的含量来调节。各种端帽（分子、低聚物或聚合物）；非官能化或被si -乙烯基或Si-H基官能化)，并提出了与实验结果一致的机理。我们的方法不仅适用于硅油，而且适用于无填料交联聚合物和一些人造硅弹性体。结果表明，当被si -乙烯基或Si-H基功能化时，所谓的“回收”聚合物可以作为通过硅氢化反应制备新型硅弹性体的反应前驱体。介绍了用100%再生有机硅制成弹性体的实例。因此，我们的方法代表了一种通过“升级”最初惰性油或通过“升级回收”最初打算报废的产品来获得活性有机硅前体的稳健方法，从这个意义上说，可以有助于丰富有机硅材料的循环模型。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

期刊介绍： Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology. Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal. However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.