双(氮丙啶)与熔融元素硫的本体自由基聚合导致脆性,交联聚合物。然而,当在有机碱基存在下用元素硫处理双(氮丙啶)时,氮丙啶与低硫阴离子发生开环反应,导致通过逐步增长聚合形成线性聚合物。这些新合成的聚合物具有含有磺酰胺或酰胺官能部分和低硫化键的重复单元,平均硫段约为2。小分子模型反应证实了元素硫与氮丙啶的亲核加成反应。已证实,S-S动态键交换是在线性链中存在有机碱的情况下发生的。合成的多硫化物与吡啶的混合物在应用于钢时表现出优异的粘合性能,和铝基板。值得注意的是,由于动态S-S交换,这些制备的粘合剂显示出良好的可重用性,并且由于其溶液可加工性而具有完全可回收性。这种涉及元素硫的聚合方法代表了合成高级含硫聚合物的创新方法,展示了在粘合剂和超越各种应用的潜力。
The bulk radical polymerization of bis(
aziridine) with molten elemental sulfur resulted in brittle, cross-linked polymers. However, when the bis(
aziridine) was treated with elemental sulfur in the presence of an organobase, the ring-opening reaction of
aziridine with oligosulfide anions occurred, leading to the formation of linear polymers by step-growth polymerization. These newly synthesized polymers possess repeating units containing a sulfonamide or amide functional moiety and oligosulfide bonds with an average sulfur segment of about two. A small molecular model reaction confirmed the nucleophilic addition reaction of elemental sulfur to
aziridine. It was verified that S-S dynamic bond exchange takes place in the presence of an organic base within the linear chains. The mixture of the synthesized polysulfides with pyridine exhibits exceptional adhesive properties when applied to steel, and aluminum substrates. Notably, these prepared adhesives displayed good reusability due to the dynamic S-S exchange and complete recyclability due to their solution processability. This elemental sulfur-involved polymerization approach represents an innovative method for the synthesis of advanced sulfur-containing polymers, demonstrating the potential for various applications in adhesives and beyond.