Ultrasonic Devulcanization of Precipitated Silica-Filled Silicone Rubber

Abstract

Abstract This investigation involves the recycling of precipitated silica-filled silicone rubber using a continuous ultrasonic reactor. The processing conditions utilized in devulcanization of the filled systems were similar to those in our previous work on unfilled systems. Significant differences were observed in devulcanization of unfilled and filled systems. A decrease in gel fraction and crosslink density was sufficient for devulcanized silica-filled silicone rubber to be reprocessed and revulcanized. The cure behavior of silicone rubber and the mechanical properties of virgin, and revulcanized rubber were measured. Results showed that unfilled silicone rubbers gave no change in vulcanizate mechanical properties after revulcanization. However, in the filled rubbers there was a decrease in the mechanical properties of revulcanizates. In order to achieve an improvement in the properties, devulcanized filled rubbers were blended with virgin filled rubber in various proportions. The obtained results indicated a considerable enhancement of the performance characteristics of these blend vulcanizates.