I. Key Properties of High-Transparency Acrylic (PMMA)
• Optical Properties: Light transmittance 92%–95% (optical grade can reach 97%), low haze, no blue tint, good color rendition, refractive index 1.49, known as "plastic crystal."
• Mechanical Properties: High surface hardness (2H–3H), wear and scratch-resistant; but high brittleness, poor impact resistance (notched impact 10–15 kJ/m²), prone to cracking.
• Thermal Properties: Long-term use temperature ≤ 70°C, heat deflection temperature ~95–105°C; softens easily at high temperatures, becomes brittle at low temperatures.
• Weather/Chemical Resistance: General grades prone to yellowing outdoors; resistant to acids, alkalis, alcohols; not resistant to solvents like ketones, esters, chloroform.
• Processing/Cost: Easy to injection mold, cast, polish, bond; lower cost.
II. Key Properties of Polycarbonate (PC)
• Optical Properties: Light transmittance 86%–89%, slightly lower than PMMA, slight inherent blue tint; low haze, small optical distortion.
• Mechanical Properties: Extremely high impact resistance (notched impact 60–80 kJ/m², 6–10 times that of PMMA), good low-temperature toughness; but low surface hardness (HB–1H), easily scratched.
• Thermal Properties: Long-term use range -40°C to 120°C, heat deflection temperature 120–140°C, far superior heat resistance compared to PMMA.
• Weather/Flame Retardancy: Good outdoor yellowing resistance with UV modification; UL94 V-2/B1 rating, self-extinguishing.
• Processing/Cost: High melt viscosity, prone to internal stress; higher price.
III. Key Differences Between PMMA and PC (At a Glance)
• Light Transmittance: PMMA (92%–95%) > PC (86%–89%)
• Impact Resistance: PC (6–10 times) >> PMMA
• Surface Hardness: PMMA (2H–3H) > PC (HB–1H)
• Heat Resistance: PC (-40~120°C) > PMMA (-20~70°C)
• Weather Resistance: PC (UV grade) > PMMA
• Flame Retardancy: PC (V-2/B1) > PMMA (flammable)
• Cost: PMMA < PC
IV. How to Choose
• Choose PMMA: When pursuing extreme transparency, high surface hardness, and low cost, such as for display stands, optical lenses, lampshades, signs.
• Choose PC: When impact resistance, high temperature resistance, flame retardancy, and long-term outdoor use are required, such as for safety helmets, goggles, automotive headlight covers, bulletproof/anti-shatter panels.
