The effect of pre-curing UV-irradiation on the crosslinking of silicone rubber

A recent work made use of selective pre-curing UV-irradiation and its effect on the kinetics of reaction of heat-cure silicone elastomers to spatially tune its viscoelastic properties and design architected solid membranes. The present study adds to the possibility of controlling the local properties of spatially graded materials by exploring the effect of key processing parameters such as the UV dose and the silicone mix thickness on the vulcanization kinetics. Dynamic Differential Scanning Calorimetry measurements have been performed showing that, over the conditions explored, the higher the UV dose, the slower the kinetics reaction. Additionally, complete crosslinking was always reached. Companion modeling effort using the Kissinger reaction model is attempted and the effects of processing parameters on the apparent activation energy are discussed. This work is a crucial first step towards the control of the processing settings needed to design architected silicone rubber membranes with spatially controlled mechanical property gradients obtained from a unique macromolecular network.