Crosslinking Of Silicone Rubber Research Articles

Isoconversional kinetic analysis for determining the rate of cross-linking for Pt and peroxide cure silicone rubbers

The cross-linking of silicone rubber can be accomplished through reactions such as cross-linking with radicals and cross-linking by addition. Here we examine the kinetics of these reactions by differential scanning calorimetry and moving die rheometry. Differential scanning calorimetry results show the importance of conducting measurements for platinum catalyzed addition cure silicone rubber as soon as possible after mixing the materials. Isoconversional kinetic analysis with the Vyazovkin method is shown to produce predictions for rate of cross-linking, which are comparable to results measured with conventionally used moving die rheometry (MDR). Moreover, the Vyazovkin method, along with MDR data, can be used for estimating the experimental lag present in MDR experiments.

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

AbstractA 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.

Morphology and properties of the PA66/PC/silicone rubber composites

AbstractThe research focused on the PA66/PC/silicone rubber composites. By adding silicone rubber as a toughener, the composites were prepared via dynamic vulcanization. The morphology and properties of the composites were characterized by FTIR, TEM, SEM, XRD, etc. The FTIR spectrum of the composites presented an increase of the 1730, 1240, and 1450 cm−1 that can be due to the CO interaction and the presence of the OCOO group, and this fact can mean the formation of the PA66–PC copolymer. The crosslinking of silicone rubber in the PA66/PC matrix formed the net‐like structure like semi‐IPN, which is propitious to enhance the interaction between PA66 matrix and PC and in further makes the PC particles embed in PA66 matrix closely. Novel composites are gained with outstanding mechanical properties and high temperature resistance, so the combine toughening by silicone rubber and PC is an ideal toughening system owing to the synergistic effect. In addition, the PA66/PC/silicone rubber/OMMT composite exhibits better flexile strength and flexile modulus without weakening other mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010