Tonkin Samuel J, Gibson Christopher T, Campbell Jonathan A, Lewis David A, Karton Amir, Hasell Tom, Chalker Justin M
Institute for Nanoscale Science and Technology , College of Science and Engineering , Flinders University , Bedford Park , South Australia 5042 , Australia . Email:
Flinders Microscopy and Microanalysis , College of Science and Engineering , Flinders University , Bedford Park , South Australia 5042 , Australia.
Chem Sci. 2020 May 15;11(21):5537-5546. doi: 10.1039/d0sc00855a. eCollection 2020 Jun 7.
Inverse vulcanization is a copolymerization of elemental sulfur and alkenes that provides unique materials with high sulfur content (typically ≥50% sulfur by mass). These polymers contain a dynamic and reactive polysulfide network that creates many opportunities for processing, assembly, and repair that are not possible with traditional plastics, rubbers and thermosets. In this study, we demonstrate that two surfaces of these sulfur polymers can be chemically joined at room temperature through a phosphine or amine-catalyzed exchange of the S-S bonds in the polymer. When the nucleophile is pyridine or triethylamine, we show that S-S metathesis only occurs at room temperature for a sulfur rank > 2-an important discovery for the design of polymers made by inverse vulcanization. This mechanistic understanding of the S-S metathesis was further supported with small molecule crossover experiments in addition to computational studies. Applications of this chemistry in latent adhesives, additive manufacturing, polymer repair, and recycling are also presented.
反向硫化是元素硫与烯烃的共聚反应，可提供具有高硫含量（通常硫质量分数≥50%）的独特材料。这些聚合物包含动态且具有反应性的多硫化物网络，为加工、组装和修复创造了许多传统塑料、橡胶和热固性材料无法实现的机会。在本研究中，我们证明了这些硫聚合物的两个表面可以在室温下通过聚合物中S-S键的膦或胺催化交换进行化学连接。当亲核试剂为吡啶或三乙胺时，我们表明只有当硫链长度>2时，S-S复分解反应才会在室温下发生——这是反向硫化制备聚合物设计中的一个重要发现。除了计算研究之外，小分子交叉实验进一步支持了对S-S复分解反应机理的理解。还介绍了这种化学方法在潜在粘合剂、增材制造、聚合物修复和回收方面的应用。
