Is Elastomer Rubber or Plastic?

Elastomers are commonly used in a variety of products, from automotive parts to medical devices. But are they considered rubber or plastic? Understanding this distinction is key to selecting the right material for your needs.

Elastomers are a type of rubber, not plastic, characterized by their high elasticity and ability to return to their original shape after being stretched.

In this article, we’ll clarify the difference between elastomers, rubber, and plastic, and explain why elastomers are classified as rubber.

What Are Elastomers?

Elastomers¹ are a special class of polymers known for their flexibility and elasticity. They are capable of stretching to several times their original length and returning to their original shape without permanent deformation. This unique property makes them ideal for applications like seals, gaskets, and tires.

Elastomers can be natural or synthetic, with rubber being the most common form.

Elastomer Characteristics

• Elasticity: Elastomers can stretch significantly and revert back to their original shape once the force is removed.
• Cross-Linking: The molecules in elastomers are cross-linked, which gives them their ability to bounce back after stretching.
• Rubber-Like Properties: Elastomers have rubber-like qualities, including flexibility, resilience, and durability.

Common Elastomers

• Natural Rubber² (NR): Obtained from latex, natural rubber is a typical elastomer used in tires and footwear.
• Synthetic Rubber³: Includes elastomers like styrene-butadiene rubber (SBR), neoprene, and nitrile rubber, produced through chemical processes for specific applications.

What Is Rubber?

Rubber is a type of elastomer that can be either natural or synthetic. It is made from polymers with strong elastic properties, allowing it to stretch and recover its shape. Rubber is widely used in a variety of products due to its durability and flexibility.

Rubber can be used as both an elastomer and a standalone material, depending on its specific properties and formulation.

Types of Rubber

• Natural Rubber: Derived from the latex of rubber trees, natural rubber has exceptional elasticity, which makes it ideal for tires and seals.
• Synthetic Rubber: Made from petroleum-based chemicals, synthetic rubbers like neoprene and butyl rubber are designed for specific applications, such as industrial machinery, medical devices, and automotive parts.

What Is Plastic?

Plastic, unlike elastomers, is a polymer that doesn’t exhibit the same level of elasticity. While plastics can be flexible, they typically do not stretch and return to their original shape in the same way elastomers do.

Plastics are generally more rigid than elastomers and do not possess the same level of stretchability or resilience.

Types of Plastic

• Thermoplastics: Plastics like polyethylene (PE) and polystyrene (PS) soften when heated and can be reshaped.
• Thermosetting Plastics: Plastics like epoxy and phenolic resins harden when heated and cannot be reformed once set.

Key Differences Between Elastomers and Plastics

Conclusion

Elastomers are a type of rubber, not plastic. They possess unique elastic properties that make them suitable for a wide range of applications requiring flexibility and resilience. While plastics are versatile materials with various applications, they lack the stretch and recovery characteristics of elastomers.