The kinetic behavior of Liquid Silicone Rubber: A comparison between thermal and rheological approaches based on gel point determination

Liquid Silicone Rubber (LSR) belongs to the category of High Temperature Vulcanization rubbers (HTVs). Due to its implementation facility, its mechanical and thermal properties and its convenience for the medical and food industries, LSR is used in a wide range of applications.In order to examine LSR kinetic performances, thermal and rheometric experimental investigations are conducted to characterize the material and discuss the kinetic model describing crosslinking behavior.The Gel Point is investigated at different temperatures to improve our understanding of the different crosslinking steps and determine which characterization method (thermal or rheological) best represents the reaction. The results show that the LSR network undergoes specific development during crosslinking. Gel point occurs before the mechanical reaction starts. Gelation behavior resembles that of a thermosetting material despite the elastomer properties confirmed by the thermal study.Finally, the thermal method seems more reliable to describe the crosslinking kinetics of LSR.