Chapter Devulcanization by Chemical and Thermomechanical Means

Thermochemistry of Sulfur-Based Vulcanization and of Devulcanized and Recycled Natural Rubber Compounds

“…In contrast, a really devulcanized rubber compound should be conceived as a formerly cured and used rubber compound which has undergone a selective mechanochemical processing targeted exclusively to break the sulfur-based crosslinks without causing the undesired main rubber chain scission as well as avoiding generalized mechanochemical oxidative degradation. These concepts were perhaps first expressed more than twenty years ago [20][21][22], were expanded by Myhre and Khait in their contribution to the book "Rubber Recycling" [23,24] and then discussed and expanded in a clearer and distinct way in a series of excellent review works specifically dedicated to devulcanization [24][25][26][27][28][29][30][31][32][33][34][35]. In the present work, we will start with the principle that vulcanization is an exothermal reaction process, we will study such exothermal reaction in a carbon black filled NR-based compound at different sulfur loadings and we will examine in a simplified model the molecular reasons linked to such exothermicity.…”