This article is dedicated to the understanding of the mechanisms involved in the evolution of the structure of a “conventionally” vulcanized rubber during thermo-oxidative (TO) aging. Based on swelling measurements, WAXS and DSC, a scenario of these mechanisms is proposed. Our results show that the crosslinking reactions are far from being complete at the end of the vulcanization process. During TO aging carried out at a moderate temperature 77 °C (350 K), the creation of long bridges first takes place via the consumption of residual sulfur; this mechanism is mainly responsible of the increase in the density of elastically active chains. The presence of residual antioxidants inhibits in the early stages of aging the chemical reactions involving oxygen. For longer aging time (here 7 days), these reactions can then occur and create "unidentified" bridges whose formation may also involves sulfur grafted onto the polymer chains. Finally, all these cross-linking reactions seem to enhance the heterogeneity of the spatial distribution of the crosslinks - already existing in the initial material - and to create highly crosslinked domains.

本文致力于了解热氧化（TO）老化过程中“常规”硫化橡胶的结构演变所涉及的机理。基于膨胀测量，WAXS和DSC，提出了这些机制的方案。我们的结果表明，在硫化过程结束时，交联反应远未完成。在温度为77°C（350 K）的中温下进行的TO老化过程中，首先通过消耗残余硫来形成长桥。该机制主要负责增加弹性活性链的密度。残留抗氧化剂的存在会在老化的早期阶段抑制涉及氧的化学反应。如果老化时间较长（此处为7天），则会发生这些反应并产生“