Improvement of the mechanical and thermal properties of silica-filled polychloroprene vulcanizates prepared from latex system

In this work, well-dispersed silica suspension having excellent storage stability was prepared by using an ultrasonic probe. The obtained silica suspension and curatives were added into the polychloroprene (CR) latex for preparing silica-filled CR latex compounds having various silica loadings. Then, the silica-filled CR vulcanizates were prepared via a dipping process. The thermal and mechanical properties of the dipped CR vulcanizates containing silica dispersed by using an ultrasonic probe were compared with those of the dipped CR vulcanizates containing silica dispersed by using a mechanical stirrer. By using thermogravimetric analysis, it could be seen that thermal resistance of the dipped CR films having silica prepared by ultrasonic probe is greater than that prepared by using the mechanical stirrer. This result corresponds well with their tensile strength after aging in the hot-air oven. In addition, modulus, tensile strength, and tear strength of the vulcanizates prepared from CR latex compounds containing silica prepared by using the ultrasonic probe are obviously greater than those prepared by using the mechanical stirrer, especially at high silica loading. This is because the silica prepared using the ultrasonic probe is uniformly distributed and dispersed throughout the CR matrix, as can be observed in the scanning electron microscope micrographs. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012