Silicone Rubber Thermal Expansion

These forces are generated by thermal expansion of the rubber and or swelling effect of a fluid.

Silicone rubber thermal expansion.

The coefficient of thermal expansion is defined as the change in length or volume of a material for a unit change in temperature. Silicones are polymers with a si o si backbone. The usual values are from 2 to 4 x 10e 4 unity ke 1. The curing method can be either vulcanized or catalyzed.

Carbons 1 2 to 2 5 x 10 6 2 16 to 4 5 x 10. There are different types depending on functional groups in the structure and curing mechanisms. This expansion is an advantage for sealing applications. There have been instances where a seal has ruptured a steel gland due to expansion when heated.

Untreated silicone in gel or liquid form will convert to solid after curing. The overall coefficient is the linear thermal expansion in per degree. 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. Silicone rubber withstands high and low temperatures far better.

Materials commonly named rubber are hot cured or high temperature vulcanisation elastomers hcr or htv. 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. 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. 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. If the seal is completely confined and the gland is 100 filled the dominating force is the force of thermal expansion of the rubber. They vary according to polymers.

Thermal expansion is usually expressed in one of two ways either volumetric expansion or more commonly linear expansion expressed as a coefficient. They expand under temperature increase influence their coefficients of linear expansion will directly be function of loads rates. Rubber and silicone lsr thermal expansion. 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.

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. Song in progress in rubber nanocomposites 2017. 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.