Silicone Rubber Thermal Expansion

Key properties include thermal stability chemical stability electrical insulation and low toxicity.

Silicone rubber thermal expansion.

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. There are different types depending on functional groups in the structure and curing mechanisms. They expand under temperature increase influence their coefficients of linear expansion will directly be function of loads rates. 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.

Silicones are polymers with a si o si backbone. This expansion is an advantage for sealing applications. Untreated silicone in gel or liquid form will convert to solid after curing. These forces are generated by thermal expansion of the rubber and or swelling effect of a fluid.

There have been instances where a seal has ruptured a steel gland due to expansion when heated. The curing method can be either vulcanized or catalyzed. Silicone rubbers are often one or two part polymers and may contain fillers to improve properties or reduce cost. The coefficient of thermal expansion is defined as the change in length or volume of a material for a unit change in temperature.

If the seal is completely confined and the gland is 100 filled the dominating force is the force of thermal expansion of the rubber. 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. 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. Main applications are flexible seals o rings etc.

The overall coefficient is the linear thermal expansion in per degree. Song in progress in rubber nanocomposites 2017. Rubber and silicone lsr thermal expansion. 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.

Materials commonly named rubber are hot cured or high temperature vulcanisation elastomers hcr or htv. 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. Thermal expansion is usually expressed in one of two ways either volumetric expansion or more commonly linear expansion expressed as a coefficient. The usual values are from 2 to 4 x 10e 4 unity ke 1.

Silicone rubber withstands high and low temperatures far better. 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 190 0 x 10 6 342 0 x 10 6 mech.