Polycarbonate (PC) vs. Delrin (POM): Selecting High-Performance Polymers for Precision Gear & Enclosure Applications
Selecting the right engineering plastic is pivotal when designing components that must withstand mechanical wear, impact, high dimensional stability, or outdoor exposure. Two of the most widely requested engineering thermoplastics at Jay Plast are Polycarbonate (PC) and Delrin / POM (Polyoxymethylene / Polyacetal).
While both are classified as high-performance engineering plastics, their molecular structures, mechanical behaviors, and ideal industrial use-cases differ significantly. In this technical comparative guide, we evaluate PC and Delrin POM across critical parameters to help injection molders, product designers, and procurement teams select the exact grade for their manufacturing needs.
1. Material Breakdown & Chemical Composition
- Polycarbonate (PC): An amorphous thermoplastic containing carbonate groups in its chemical structure. Because of its amorphous nature, PC is naturally transparent, tough, and possesses high optical clarity alongside extreme impact resistance.
- Delrin / POM (Polyoxymethylene): A highly crystalline thermoplastic characterized by repeating oxymethylene units. POM is available as a homopolymer (trademarked as Delrin by DuPont) or copolymer (such as Duracon or Hostaform). It is famous for its high stiffness, low friction, and exceptional dimensional stability under mechanical load.
2. Head-to-Head Technical Comparison
| Performance Characteristic | Polycarbonate (PC) | Delrin / POM | Winner for Application |
|---|---|---|---|
| Impact Strength (Izod) | Extremely High (600–850 J/m) | Moderate (60–110 J/m) | Polycarbonate (PC) |
| Coefficient of Friction | High (High internal friction) | Extremely Low (Self-lubricating) | Delrin / POM |
| Tensile Strength & Rigidity | High (60–75 MPa) | Very High (65–85 MPa) | Delrin / POM |
| Wear & Abrasion Resistance | Fair (Susceptible to surface scratching) | Exceptional (High cyclic fatigue resistance) | Delrin / POM |
| Transparency & Optical Clarity | Water-clear glass transparency | Opaque / Semi-translucent white | Polycarbonate (PC) |
| Chemical Resistance | Sensitive to aromatic hydrocarbons & alkalis | High resistance to fuels, solvents, & alkalis | Delrin / POM |
| Dimensional Stability | Moderate (Low mold shrinkage, low moisture absorption) | Superior (Very low creep, excellent memory retention) | Delrin / POM |
3. Deep Dive into Key Engineering Characteristics
A. Coefficient of Friction & Wear Resistance (Gears & Bearings)
- Delrin POM: Unmatched in dynamic mechanical applications. Delrin exhibits a low static and dynamic coefficient of friction, rendering it self-lubricating. It resists stick-slip phenomenon, making it the industry standard for precision gears, conveyor links, bushings, sliding bearings, and zipper teeth.
- Polycarbonate: Poor self-lubrication. PC on PC contact leads to galling and premature wear. Avoid using PC for high-frequency moving parts or mating gears.
B. Impact Resistance & Toughness (Enclosures & Housings)
- Polycarbonate: PC is virtually unbreakable under normal operating conditions. It absorbs massive energy upon impact without shattering, making it the preferred resin for electrical meter covers, automotive headlamps, protective face shields, and consumer electronic housings.
- Delrin POM: Notch sensitive compared to PC. While rigid, sudden high-energy impacts can cause stress concentration failures if sharp internal radii exist.
C. Chemical & Environmental Exposure
- Polycarbonate: Sensitive to strong solvents, brake fluids, and strong alkaline cleaning agents. Stress cracking can occur if PC is exposed to harsh chemical vapors under load unless UV-stabilized or alloyed (such as PC+ABS or PC+PBT).
- Delrin POM: Highly resistant to fuels, organic solvents, neutral oils, and greases. Excellent choice for automotive fuel system components, pump impellers, and industrial valves.
4. Processing & Injection Molding Tips
Polycarbonate (PC) Processing:
- Drying is Crucial: PC hydrolyzes rapidly at melt temperatures if wet. Always dry virgin or reprocessed PC granules at 120°C for 3–4 hours to achieve moisture levels below 0.02%.
- High Melt Temperatures: Melt temperature ranges from 280°C to 320°C. Ensure robust mold heating (80°C–110°C) to minimize molded-in stress.
Delrin / POM Processing:
- Drying: POM absorbs less moisture than PC or Nylon, but pre-drying at 80°C–90°C for 2 hours ensures defect-free surface finish.
- Thermal Degradation: Do NOT overheat POM above 230°C or leave melt stagnant in the barrel. Overheating degrades POM into formaldehyde gas, causing severe outgassing and voiding.
5. Summary Recommendation Matrix
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Choose Polycarbonate (PC) if your project requires:
- Glass-like optical transparency or light transmission.
- Maximum shatterproof impact resistance for housings and protective covers.
- High heat deflection temperatures (HDT up to 135°C–140°C).
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Choose Delrin / POM if your project requires:
- Precision gears, cams, rollers, bearings, or snap-fit fasteners.
- Low friction and high cyclic fatigue resistance without external lubricants.
- Resistance to fuels, solvents, and moisture-rich environments.
Source High-Grade PC & Delrin POM Granules from Jay Plast
At Jay Plast, we supply prime virgin and high-grade reprocessed PC and Delrin / POM granules engineered to meet precise melt flow index (MFI) and mechanical specifications. Whether you are compounding or injection molding in Mumbai or across India, our technical experts are here to match the ideal grade for your application.
Contact Jay Plast today for technical data sheets (TDS) and live market pricing per kg!