Understanding Plastics and Elastomers: Key Differences for Industrial Applications

Plastics and elastomers are essential materials in industries ranging from automotive manufacturing to medical devices. While both are polymers (long chains of repeating molecules), their properties and applications differ significantly. This guide breaks down their technical distinctions, backed by industry research and data, to help you make informed material choices.

1. Plastics and Elastomers: Core Definitions

What Are Plastics?

Plastics are synthetic polymers made from monomers like ethylene or propylene. They are categorized into two types:

• Thermoplastics (e.g., polyethylene, PVC): Soften when heated and harden when cooled, allowing reshaping.
• Thermosets (e.g., epoxy, phenolic): Harden permanently after curing and cannot be remelted (Valve Magazine).

What Are Elastomers?

Elastomers, often called rubbers, are polymers with elastic properties. Their molecular chains are cross-linked, enabling them to stretch over 100% and return to their original shape. Common examples include silicone and EPDM (Osborne Industries).

2. Differentiate Between Rubber and Plastic: Key Comparisons

Property	Plastics	Elastomers
Elasticity	Low (≤ 10% stretch)	High (100–700% stretch)
Heat Resistance	Varies: PE (80°C), PEEK (250°C)	Moderate: Silicone (230°C), EPDM (150°C)
Recyclability	Thermoplastics: Yes; Thermosets: No	Limited (cross-linked structure)

3. Mechanical Properties: Strength vs. Flexibility

Elastomeric Behavior

Elastomers absorb mechanical stress through their coiled molecular structure. For instance, silicone O-rings stretch to seal gaps under pressure but return to shape when the load is removed (PMC Study).

Plastic Rigidity

Plastics like polycarbonate maintain shape under static loads but can crack under sudden impact. PVC pipes handle steady water pressure but may fail if bent repeatedly.

4. Thermal Behavior: Heat Resistance and Molding

Plastics

• Thermoplastics: Melt at 120–260°C, allowing remolding (e.g., PET bottles).
• Thermosets: Withstand higher temps but char instead of melting.

Elastomers

• Heat Resistance: Degrade above 150–230°C. Silicone withstands sterilization temps in medical devices.

5. Applications: Where Each Material Excels

Plastics in Industry

• Automotive: Polypropylene dashboards, ABS brake components.
• Medical: Disposable syringes (polyethylene).

Elastomers in Action

• Sealing Solutions: EPDM sleeve in pinch valve resist steam and chemicals.

6. Recyclability and Environmental Impact

Plastics

• Thermoplastics: Recycled 3–7 times before quality loss (e.g., HDPE bottles).

Elastomers

• Recycling: Crumb rubber from tires is repurposed for playground surfaces.

7. Rubber and Elastomers: Clarifying Terminology

• Rubber: A subset of elastomers, including natural and synthetic types.
• Elastomer: Broader term covering all elastic polymers, including thermoplastic elastomers (TPE).

Conclusion

Plastics provide structural integrity, while elastomers deliver flexibility. Understanding their differences ensures optimal material selection for industrial durability and performance.