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Understanding Silicone Rubber: Properties & Applications

Elastomers are polymers with a coiled molecular structure, giving them high elasticity. The term “elastomer” is a blend of “elastic” and “polymer.” This unique material possesses critical properties that make it suitable for various industries, including healthcare, construction, aerospace engineering, and transportation.

In this comprehensive guide, we will explore different types of elastomers and examine their most common industrial applications. By gaining a deeper understanding of their properties and characteristics, you can make more informed decisions about which elastomer best suits your specific industrial needs.

Types of Elastomers

Elastomers can be classified into two categories: saturated elastomers and unsaturated elastomers. The key differences between these two types make them suitable for distinct applications.

Molecular Structure of Elastomers – Saturated Elastomers

One of the defining characteristics of saturated elastomers is their stability when exposed to external factors such as temperature, ozone, oxygen, and radiation. Since their polymer chains are fully saturated, they exhibit minimal reactivity to environmental conditions, making them highly adaptable.

From a chemical perspective, saturated elastomers have polymer chains composed of carbon atoms connected by single bonds, which results in lower chemical reactivity.

Examples of Saturated Elastomers and Their Common Uses:

Silicone Rubber: Seals, gaskets, electrical insulation
Polyacrylate Rubber (ACM): Automotive components, vibration damping
Fluorosilicone Rubber (FVMQ): Aerospace components and parts exposed to fuel or petroleum

Molecular Structure of Elastomers – Unsaturated Elastomers

Unlike saturated elastomers, unsaturated elastomers contain carbon-carbon double or triple bonds. These unsaturated bonds make them more chemically reactive.

Unsaturated elastomers can undergo sulfur vulcanization, a process in which individual polymer chains cross-link, forming a more robust and durable material. Because of their increased strength, unsaturated elastomers are more widely used in industrial applications.

Examples of Unsaturated Elastomers and Their Common Uses:

Butyl Rubber (IIR): Tires, sports equipment
Natural Rubber (NR): Medical devices, children’s toys
Polybutadiene Rubber (BR): Footwear, automotive components

Key Properties and Advantages of Elastomers

Different elastomers exhibit distinct performance characteristics. For example, silicone rubber (a saturated elastomer) can withstand much higher temperatures than butyl rubber (an unsaturated elastomer). Understanding these differences is crucial for selecting the right material for specific applications.

✔ Elasticity and Flexibility: The primary distinction between elastomers and other polymers is their elasticity. Due to their unique molecular structure, elastomers can endure significant stretching forces and return to their original shape once the force is removed. To optimize their performance, unsaturated elastomers often require vulcanization to enhance their elasticity.

✔ Melting Point: Saturated elastomers have exceptionally high melting points. Several factors influence the actual melting temperature, such as the duration of exposure to extreme conditions. Silicone rubber, for instance, can withstand intermittent exposure to temperatures up to 300°C (572°F) without permanent deformation. It also remains stable at extremely low temperatures, down to -60°C (-76°F), without undergoing physical or chemical changes.

✔ Durability: In high-pressure environments, materials must be highly durable and resilient under harsh conditions. Compared to many other manufacturing materials, elastomers offer superior durability and high tear resistance, ensuring enhanced performance and extended service life.

✔ Chemical Resistance: While many elastomers exhibit good chemical resistance, their effectiveness depends on the material type and the chemicals they come into contact with.

For example, silicone rubber maintains excellent performance when exposed to various acids but tends to swell when in contact with oil or petroleum-based substances. In contrast, nitrile rubber (NBR) is highly resistant to industrial fluids such as oils, greases, and alcohol, making it a preferred choice for automotive powertrain components and industrial machinery.

Market Applications of Elastomers

As highlighted earlier, selecting the right elastomer with the most suitable properties is essential for each application. While all elastomers share some characteristics, their physical properties and industrial uses vary significantly.

From everyday consumer products to high-tech industrial components, elastomers are widely utilized across multiple sectors. Here are three of the most common applications:

Automotive Industry

We interact with elastomers almost daily without even realizing it. In automobiles, elastomers are commonly used in tires, windshield wipers, seals, and gaskets.

Due to their high flame resistance and low smoke emission, elastomers are also extensively used in the railway and public transportation sectors, including HVAC gaskets, electronic housing seals, and vibration-damping flooring systems. These applications play a crucial role in enhancing passenger safety and comfort.

Medical Devices & Healthcare

A wide range of medical devices incorporate elastomers due to their unique advantages. Examples include oxygen masks, catheters, implants, prosthetics, and IV systems. They are also essential in personal protective equipment (PPE), such as latex gloves and face masks.

During the pandemic, silicone rubber played a vital role in safeguarding patients, healthcare professionals, and the general public. To learn more, explore our case study on silicone rubber applications in face masks.

Construction Industry

Elastomers are widely used in construction due to their chemical robustness and versatility. One of their primary applications is in seals and gaskets, which protect buildings from environmental exposure.

Additionally, elastomers are crucial for vibration management, enhancing structural safety and longevity.

Choosing the Right Material

Elastomers offer numerous advantages across diverse industries and projects. However, given the vast variety of elastomer types, understanding which one best suits your specific needs is critical.

Elastomers are present in both cutting-edge innovations and everyday products, offering solutions to complex engineering challenges. A thorough understanding of their properties can provide a significant competitive edge in various industries.

If you have any silicone rubber requirements, don’t hesitate to contact our expert team today!