Silicone Rubber Thermal Expansion

Silicone rubber is an elastomer rubber like material composed of silicone itself a polymer containing silicon together with carbon hydrogen and oxygen silicone rubbers are widely used in industry and there are multiple formulations.

Silicone rubber thermal expansion.

These forces are generated by thermal expansion of the rubber and or swelling effect of a fluid. 2 2 4 silicone rubber sir silicone rubber sir is an elastomer composed of silicone containing silicon carbon hydrogen and oxygen in the form of a polymer. Silicone rubbers are often one or two part polymers and may contain fillers to improve properties or reduce cost. Rubber and silicone lsr thermal expansion.

If the seal is completely confined and the gland is 100 filled the dominating force is the force of thermal expansion of the rubber. There have been instances where a seal has ruptured a steel gland due to expansion when heated. Thermal expansion is usually expressed in one of two ways either volumetric expansion or more commonly linear expansion expressed as a coefficient. The curing method can be either vulcanized or catalyzed.

Untreated silicone in gel or liquid form will convert to solid after curing. For example silicone may expand linearly 5 9e 4 to 7 9e 4 in in c compared to aluminum at 23 0e 6 in in c or steel at 10 8e 6 in in c. This expansion is an advantage for sealing applications. Thermal expansion can present significant challenges for designers in certain areas for example when constructing spacecraft aircraft buildings or bridges but it can have positive uses.

The overall coefficient is the linear thermal expansion in per degree. The usual values are from 2 to 4 x 10e 4 unity ke 1. Silicone rubber 190 0 x 10 6 342 0 x 10 6 mech. Silicone rubber withstands high and low temperatures far better.

The coefficient of thermal expansion is defined as the change in length or volume of a material for a unit change in temperature. Key properties include thermal stability chemical stability electrical insulation and low toxicity. Calculate the length change of a bronze bar l 5m α 18 10 6 c if the temperature rises from 25 c to 75 c. Silicone rubber for low temperature applications ke 136y general purpose silicone rubber ke 951 nitrile rubber chloroprene rubber chloroprene rubber deteriorates rapidly and discolors at temperatures between 150 250 c but there is little change in silicone rubber even at 250 c.

Main applications are flexible seals o rings etc. The coefficient of volumetric thermal expansion for all silicone rubber products is in the range of 5 9 to 7 9 x 10 4 4 c. Silicones are polymers with a si o si backbone. Coefficient of thermal expansion silicone has a high thermal expansion coefficient and can be used as a temperature activation method or sensor in the design.

There are different types depending on functional groups in the structure and curing mechanisms. Song in progress in rubber nanocomposites 2017. They vary according to polymers.