Tag Archive

Why Only Hollow LSR Parts Float on Water

The density, or its reciprocal, the specific volume, is a commonly used property for polymeric materials. Density is primarily used as a material control tool, as well as to compare the buoyancy of different materials, but it can also be used to calculate the mass of rubber required to produce a given volume of material. The density of compounds with fillers or different materials can be computed at any temperature using the rule of mixture. Density measurements are performed following the standard tests ISO 1183 and ASTM D792. The density of Liquid Silicone Rubber (LSR) is typically in the range of 1.10 – 1.50 g/cm3 (density of natural rubber: 0.92, EPDM: 0.86 g/cm3), so it will sink in water (density of water: 1 g/cm3).