Novel room-temperature-vulcanized silicone rubber/calcium sulfate whisker composites have been prepared. Properties such as viscosity, hardness, tensile strength, elongation at break, and thermal stability were researched and compared. A combination of scanning electronic microscopy studies was used to characterize the structure and reinforcing mechanism of calcium sulfate whisker. Results showed that the addition of 10% calcium sulfate whisker-Y into room-temperature-vulcanized composites improved the tensile strength from 4.2 to 5.0 MPa and elongation at break from 210 to 590%. In addition, some improvement in thermal stability was obtained between 350 and 700°C for room-temperature-vulcanized systems.

The aim of this work was to study preparation and characterisation of layered double hydroxides (LDHs) and their effects on the mechanical and flame-retardant properties of ethylene propylene diene (EPDM) polymer. A series of Mg-Al, Ni-Al, and Cu-Al hydrotalcite-like compounds were prepared. The surface morphology, interlayer space, interlamellar structure, and thermal properties of these LDHs were investigated. Results showed that a best thermal stability could be obtained with Cu-Al-LDHs as the most effective components. EPDM/Cu-Al-LDHs composites were prepared by conventional compounding with EPDM and Cu-Al type of LDHs. The cure characteristics, tensile strength, wear resistant, and flame-retardant properties were investigated. The best properties were observed for 10 phr of Cu-Al-LDHs filled composite, which resulted in no obvious changes of tensile strength, increased thermal stability, 45% decrease in abrasion loss, and 53% increase in vertical burning time, respectively, compared to that of pure EPDM matrix.