Synthetic Rubber

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Synthetic Rubber — Note

Synthetic Rubber

1. Introduction

Synthetic rubber is an artificial elastomer produced by the polymerisation of monomers derived from petroleum or chemical sources. It mimics the properties of natural rubber but offers better chemical, heat, and aging resistance. Widely used in industrial, automotive, and consumer products.

2. Types of Synthetic Rubber

Type Monomer / Composition Properties / Notes
SBR (Styrene-Butadiene Rubber) 75% Butadiene + 25% Styrene Good abrasion resistance; used in tyres
NBR (Nitrile Butadiene Rubber) Butadiene + Acrylonitrile Oil and fuel resistant; gaskets, hoses
Neoprene (Polychloroprene) Chloroprene CH2=CCl–CH=CH2 Weather, oil, and chemical resistant; gloves, wetsuits
Butyl Rubber (IIR) Isobutylene + Isoprene Excellent air impermeability; inner tubes
EPDM Ethylene + Propylene + Diene Heat, ozone, and weather resistant; roofing, hoses
Polyurethane Rubber (PU) Diisocyanates + Polyols Tough, abrasion-resistant; seals, rollers

3. Methods of Polymerisation

  • Free Radical Polymerisation: Used for SBR; monomers Styrene + Butadiene
  • Ionic Polymerisation: Cationic or anionic; controls polymer microstructure
  • Emulsion Polymerisation: Monomers dispersed in water with surfactants; controls particle size and properties

4. Properties

  • Elasticity: comparable to natural rubber, high flexibility
  • Abrasion Resistance: improved, depends on type
  • Chemical Resistance: resists oils, fuels, acids, alkalis
  • Thermal Stability: better than natural rubber; EPDM & Neoprene excellent
  • Water Resistance: Butyl & Neoprene resist water and air permeability
  • Aging Resistance: more resistant to oxidation and ozone

5. Advantages

  • Uniform quality and controlled properties
  • Better chemical, heat, and weather resistance
  • Tailored for specific applications
  • Reduces dependency on natural latex

6. Limitations

  • Often less elastic than natural rubber (SBR)
  • Requires more processing chemicals
  • Can be more expensive depending on type
  • Non-biodegradable; environmental concerns

7. Industrial Applications

Synthetic Rubber Type Applications
SBR Tyres, conveyor belts, footwear
NBR Oil-resistant hoses, seals, gaskets
Neoprene Wetsuits, gaskets, industrial gloves
Butyl Rubber Inner tubes, air bladders, pharmaceutical stoppers
EPDM Roofs, automotive weather stripping, hoses
Polyurethane Seals, rollers, sports goods, coatings

8. Summary

Synthetic rubber is a versatile elastomer supplementing or replacing natural rubber. Its tailored properties, chemical and thermal resistance, and industrial scalability make it indispensable in modern industries, especially in automobile, aerospace, and consumer products.

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