The influence of devulcanization and revulcanization on sulfur crosslink types: Recycling of ground tyre rubber

Devulcanized rubber could be a valuable material feedstock to help manufacture sustainable rubber products. However, the differences in chemistry and structure of devulcanized rubber have limited industrial uptake. This work demonstrates how devulcanization affects the concentration and ratios of mono-, di- and poly- sulfidic crosslinks. These residual crosslinks make devulcanized rubber chemically dissimilar from virgin rubber, affecting (re)vulcanization. The hypothesis that sulfur rank of revulcanized material can be modified by sulfur/accelerator ratio was evaluated by two different cure packages. Despite substantial differences in accelerator/sulfur ratio, both recycled rubber compounds favoured formation of poly-sulfidic crosslinks.脱硫化橡胶（devulcanized rubber）可作为极具价值的原料，用于制备可持续橡胶制品。然而，脱硫化橡胶在化学组成与微观结构上的差异，限制了其工业推广应用。本研究阐明了脱硫化工艺对单硫、双硫及多硫交联键浓度与比例的影响机制。这些残留交联键使得脱硫化橡胶在化学性质上区别于未硫化生胶（virgin rubber），进而对其再硫化过程产生影响。本研究通过两种不同硫化体系（cure packages），验证了“再硫化产物的硫交联键分布可通过硫与促进剂的配比进行调控”这一假说。尽管两种体系的促进剂与硫的配比存在显著差异，但两种再生橡胶胶料均更倾向于生成多硫交联键。