Preparation and characteristic of novel silicone rubber composites based on organophilic calcium sulfate whisker

Abstract

Two types of organic modification agents, hydrogen silicone oil and silane coupling agent, were used in the preparation of novel organic calcium sulfate whiskers (OCSW-H and OCSW-K). Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis were used to investigate the structure and properties of these surfactant-modified calcium sulfate whiskers (CSWs). Liquid silicone rubber (LSR) composites were prepared by the two types of OCSW. The properties such as tensile strength, elongation at break, and thermal stabilities were studied and compared. It was observed that addition of OCSW can improve the tensile and thermal properties of the silicone rubber composites. The tensile strength of LSR/OCSW-K-20% was about 60% higher than that of the CSW filled composites, and the elongation at break also showed an enhancement. Thermogravimetric tests showed that the center temperature of thermal degradation was improved from about 450 to 520 °C, and the degradation degree decreased a lot in the temperature range 400∼700 °C. A combination of scanning electron microscopy and swelling test was used to characterize the structure and reinforcing mechanism of OCSW. The reactions between the modification agent and the component of LSR were regarded as the key factors affecting the compatibility between OCSW and LSR composites.