Organisations in a range of industries benefit from the use of EPDM and silicone rubber. Each material offers different benefits and has advantages that may be perfect for your business needs. So what are the differences and how do you know which is right for you?
What is silicone rubber?
Silicone is a synthetic polymer which is created from the chemical element silicon. Made by combining silicon with hydrogen, carbon, and oxygen, it results in a heat-resistant and flexible material used in a variety of industries including food and milk, medical, and mass transit.
What is EPDM?
EPDM is Ethylene Propylene Diene Monomer, a type of synthetic rubber. Resistant to various environmental factors, it is popular within automotive and construction organisations. There are a number of similarities between EPDM and silicone rubber, which can make it challenging to know which is right for you.
The key differences between EPDM and silicone rubber
Both materials are flexible, durable, and resistant to heat and environmental factors. However, there are subtle differences between the two and one may be better suited to a different environment than another. The EPDM and silicone rubber properties will vary depending on its treatment and the creation process.
One of the reasons that silicone rubber and EPDM are such popular materials to use is that they are resistant to heat. They can both withstand cold and hot temperatures, although how much they can handle before degrading varies on the material.
Silicone rubber has the advantage in this area. It has a greater range, with the silicone temperature range allowing it to reach as hot as 300°c before degrading and as low as -50°c before reaching its brittle point.
EPDM, on the other hand, will start to degrade at temperatures exceeding 130°c and become brittle at -40°c. When exposed to different temperatures, the size and shape of EPDM can change drastically, demonstrating as much as 50% shrinkage.
Tensile strength and tear strength
Silicone is an extremely durable material, capable of withstanding abrasions and fatigue. This is because it is a flexible material and can be created to be more resistant to tearing.
EPDM typically is recognised as being more durable than rubber when compared to silicone, as it is more resistant to tearing. However, Viking Extrusions can formulate specialist-grade silicone to improve the tear resistance and elongation of the product.
The tensile strength of EDPM is approximately 17 Mpa, while silicone rubber’s tensile strength can be anywhere between 4-12 Mpa.
Shore A/Hardness and elongation
The Shore A/Hardness refers to the hardness of flexible old rubbers. Silicone and EPDM are known as offering great flexibility, depending on the way it has been formulated and treated. EPDM has a hardness of 30°-90°, while silicone rubber has 20°-80°, making them similar in terms of their flexibility. However, many consider silicone rubber to be the more flexible, as it can withstand tearing more easily. Your business may require a different shore hardness depending on the application.
For elongation, EPDM reaches a 300% elongation following a fracture, while silicone rubber is more likely to retain its shape and length with elongation after fracture of 90–920%.
The density of silicone rubber and EPDM may make it unsuitable for the application you wish to use it in. They are relatively close in density, but the difference in how tightly these materials are packed together could mean it doesn’t perform as well as expected.
EPDM has a density of 0.86 g/cm3, while silicone rubber varies between 1.1-1.6 g/cm3. This typically means that silicone is denser and often more durable, making it ideal for more rigorous projects.
Ozone and UV resistance
Your equipment often has to withstand harsh conditions, especially within specific industries. Mass transit, aerospace, marine and more require material to withstand environmental factors.
Both EPDM and silicone rubber have excellent resistance to environmental conditions including exposure to ozone and UV, as well as general weathering.
Chemical and oil reactivity
Materials used in manufacturing, construction, and a number of other applications must not react to chemicals and oils in order to maintain the integrity of the overall product. EDPM and silicone are both prone to swelling when exposed to oil for extended periods of time.
If you believe that the conditions will require extensive exposure, you will find that silicone is more resistant. At Viking Extrusions, we can create specialist-grade silicone more resistant to oil to ensure you have the best product for your needs.
Silicone vs EPDM
Both EPDM and silicone rubber can be formulated to suit your business needs. In the battle of EPDM vs silicone, they are both pretty comparable. However, silicone rubber is one of the most popular materials in the world, thanks to its flexibility, temperature resistance, and ability to withstand environmental hazards, making it the obvious winner for many businesses.
At Viking Extrusions, we have produced over 8,000 silicone rubber profiles throughout the years. We work with customers in almost all industries, including aerospace, civil engineering, energy generation, pharmaceutical and more. Want to know if silicone rubber is right for you? Contact our team today to discuss your needs.