Polycarbonate (PC) is a versatile thermoplastic polymer containing carbonate groups that combine strength, transparency, and moldability. This engineered material serves as a cornerstone in modern manufacturing and construction.
Physical Properties Define Performance
Polycarbonate exhibits remarkable physical characteristics with a density of 1.20-1.22 g/cm³ and exceptional optical clarity with a refractive index of 1.584-1.586. The material maintains structural integrity across temperatures from -40°C to 130°C and demonstrates high impact resistance with an Izod strength of 600-850 J/m.
Manufacturing Creates Versatility
Chemical Synthesis Enables Production
Two main routes produce polycarbonate:
- The phosgene process reacts bisphenol A with phosgene to create the polymer chain
- The transesterification method uses diphenyl carbonate instead of phosgene
Processing Methods Shape Applications
The material transforms through:
- Injection molding for complex parts
- Extrusion for sheets and films
- Thermoforming for curved shapes
Applications Span Industries
Consumer Electronics Lead Usage
Polycarbonate dominates electronic device manufacturing, providing:
- Durable smartphone cases
- Protective laptop housings
- Data storage in CDs and DVDs
Construction Demands Strength
The construction industry utilizes polycarbonate for:
- Transparent roofing panels
- Security glazing
- Sound barrier walls
Safety Equipment Requires Toughness
Critical safety applications include:
- Protective eyewear
- Riot shields
- Bullet-resistant windows
Environmental Considerations Matter
Chemical Stability Raises Concerns
The material can release bisphenol A (BPA) through:
- Hydrolysis at elevated temperatures
- Exposure to certain cleaning agents
- Natural degradation over time
Recycling Presents Challenges
Environmental impacts include:
- Persistence in landfills
- Potential water contamination
- UV degradation products
The material continues to evolve with new BPA-free formulations and enhanced recycling methods, addressing environmental concerns while maintaining its essential role in modern manufacturing.
Citations:
https://en.wikipedia.org/wiki/Polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily worked, molded, and thermoformed. Because of these properties, polycarbonates find many applications. Polycarbonates do not have a unique resin identification code (RIC) and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A (BPA).
| Polycarbonate | |
|---|---|
 Repeating chemical structure unit of Polycarbonate made from bisphenol A  | |
| Physical properties | |
| Density(ρ) | 1.20–1.22 g/cm3 |
| Abbe number(V) | 34.0 |
| Refractive index(n) | 1.584–1.586 |
| Flammability | HB-V2 |
| Limiting oxygen index | 25–29% |
| Water absorption—Equilibrium (ASTM) | 0.16–0.35% |
| Water absorption—over 24 hours | 0.1% |
| Ultraviolet(1–380 nm) resistance | Fair |
| Mechanical properties | |
| Young's modulus(E) | 2.0–2.4 GPa |
| Tensile strength(σt) | 55–75 MPa |
| Elongation(ε)at break | 80–150% |
| Compressive strength(σc) | >80 MPa |
| Poisson's ratio(ν) | 0.37 |
| Hardness—Rockwell | M70 |
| Izod impact strength | 600–850 J/m |
| Notch test | 20–35 kJ/m2 |
| Abrasive resistance ASTM D1044 | 10–15 mg/1000 cycles |
| Coefficient of friction(μ) | 0.31 |
| Speed of sound | 2270 m/s |
| Thermal properties | |
| Glass transition temperature(Tg) | 147 °C (297 °F) |
| Heat deflection temperature |
|
| Vicat softening point at 50 N | 145–150 °C (293–302 °F) |
| Upper working temperature | 115–130 °C (239–266 °F) |
| Lower working temperature | −40 °C (−40 °F) |
| Thermal conductivity(k) at 23 °C | 0.19–0.22 W/(m·K) |
| Thermal diffusivity(a) at 25 °C | 0.144 mm²/s |
| Linear thermal expansion coefficient(α) | 65–70 × 10−6/K |
| Specific heat capacity(c) | 1.2–1.3 kJ/(kg·K) |
| Electrical properties | |
| Dielectric constant(εr) at 1 MHz | 2.9 |
| Permittivity(ε) | 2.568 × 10−11 F/m |
| Relative permeability(μr) at 1 MHz | 0.866(2) |
| Permeability(μ) at 1 MHz | 1.089(2) μN/A2 |
| Dissipation factor at 1 MHz | 0.01 |
| Surface resistivity | 1015 Ω/sq |
| Volume resistivity(ρ) | 1012–1014 Ω·m |
| Chemical resistance | |
| Acids—concentrated | Poor |
| Acids—dilute | Good |
| Alcohols | Good |
| Alkalis | Good-Poor |
| Aromatic hydrocarbons | Poor |
| Greases and oils | Good-fair |
| Halogenated hydrocarbons | Good-poor |
| Halogens | Poor |
| Ketones | Poor |
| Gas permeation at 20 °C | |
| Nitrogen | 10–25 cm3·mm/(m2·day·Bar) |
| Oxygen | 70–130 cm3·mm/(m2·day·Bar) |
| Carbon dioxide | 400–800 cm3·mm/(m2·day·Bar) |
| Water vapour | 1–2 g·mm/(m2·day) @ 85%–0% RH gradient |
| Economics | |
| Price | 2.6–2.8 €/kg |