A highly versatile material, Silicone Sponge combines sponge rubber’s enhanced sealing properties with lightness of foam. The sponge is soft, malleable with a wide temperature resistance, plus the ability to withstand shocks and repel water. Compared to most rubber material, silicone sponge has superb compression set resistance (this is the sponge’s ability to rebound to original thickness after compressive pressure is removed), especially at higher temperatures.
These properties have led to them being used for sealing purposes by the medical, food processing and pharmaceutical industries. However, how is the material made?
Silicone sponge is made of a fine cellular construction that is mainly composed of non-interconnecting cells. Most silicone sponge currently commercially available on the market is created from the gum-based polydimethylsiloxane (PMDS). PMDS is the most widely used silicone inorganic polymer today. The polymer is chemically inert and non-flammable, making it a popular choice for industrial purposes.
When heat cured, the silicone elastomer expands, creating a closed-cell sponge structure. The expanding process creates compressible air pockets in a manner similar to when yeast is added to bread. The resulting expanded closed-cell sponge has many of the performance advantages of solid silicone, but in a form that is more softer and malleable.
The sponge is a highly compressible material that is ideal for creating seals. Thanks to its closed cell construction, it absorbs little moisture and is therefore a good water-seal even when only subjected to low compressive forces. The sponge can also withstand a wide range of temperatures, from -60c to 260c, as well as UV and ozone resistance. Additionally, silicone sponge has superb vibration isolation qualities and is able to reduce the effects of shocks to any item it is used to protect.