Polycarbonate vs Acrylic: Impact vs Clarity Compared
Polycarbonate (PC) and acrylic (PMMA) are the two dominant transparent engineering plastics. Both are clear, lightweight alternatives to glass — but they solve different problems. Polycarbonate is virtually unbreakable under impact (30× the impact strength of acrylic) and handles higher temperatures. Acrylic transmits slightly more light (92% vs 88%), resists UV weathering better in standard grades, scratches less easily, and costs 20–40% less. The wrong choice in a security glazing, display cover, or outdoor sign can mean a cracked panel or a yellowed lens.
TL;DR
- Impact strength: PC is 30× stronger than acrylic in impact — the standard choice for safety glazing, machine guards, and ballistic-rated panels.
- Light transmission: Acrylic transmits 92% of light vs PC's 88%; both beat glass (~90%).
- Scratch resistance: Acrylic is naturally harder and more scratch-resistant; PC scratches easily without a hard-coat.
- UV weathering: Standard acrylic weathers better; UV-stabilized PC grades narrow the gap.
- Temperature: PC handles 240°F (116°C) continuous vs acrylic's 170°F (77°C).
- Chemical resistance: Acrylic resists more chemicals; PC is attacked by many solvents and aromatic hydrocarbons.
- Cost: Acrylic runs 20–40% less than PC for equivalent sheet thicknesses.
Comparison Table
When to Choose Polycarbonate
Safety Glazing and Machine Guards
When panels must protect against impact, flying debris, or accidental contact, polycarbonate is the standard. At 30× the impact strength of acrylic, PC panels resist breakage from tool drops, kicked parts, and operator contact. Machine guarding standards (OSHA 1910.212, ANSI B11) frequently specify PC or equivalent high-impact transparent material. Acrylic panels in the same guards shatter — creating secondary hazards.
Ballistic and Security Panels
PC is the core material in multi-layer ballistic glazing (often laminated with glass or other polymers). Bulletproof windows, bank teller windows, and security screens use PC because acrylic's low impact strength and brittleness make it fundamentally unsuitable. Even in non-ballistic security applications — vandal-resistant signage, prison windows, storm shelters — PC's toughness is the governing property.
High-Temperature Applications
Polycarbonate's 240°F (116°C) continuous service rating covers applications where acrylic fails: lighting fixtures above incandescent or LED drivers, automotive interior covers near heat vents, and enclosures in warm industrial environments. Acrylic's 170°F (77°C) limit rules it out for many lighting and automotive uses.
Complex Thermoformed Shapes with Tight Radii
PC's lower forming temperature range (~180–230°F before detail memory softening) and high toughness allow deep draws and tight radii without cracking on release. Complex safety helmet visors, instrument covers, and blister-formed protective covers leverage PC's forming characteristics.
When to Choose Acrylic
Maximum Light Transmission and Optical Clarity
For display cases, retail showcases, aquarium panels, picture glazing, and point-of-purchase displays, acrylic's 92% light transmission and excellent color neutrality make it the premium optical choice. Where you stand in front of a display and want zero color shift, acrylic wins. PC's slightly lower transmission and occasional warm tint are visible side-by-side in controlled lighting.
Outdoor Signage and UV-Exposed Applications
Standard cast acrylic does not yellow in UV exposure the way standard PC does. For outdoor signs, greenhouse panels, skylights, and illuminated displays exposed to direct sunlight, acrylic's long-term color stability is a major advantage. UV-stabilized PC grades have improved significantly, but standard cast acrylic remains the benchmark for outdoor durability in transparent plastics.
Scratch-Resistant Surfaces
Acrylic's Rockwell hardness (M93–M102) is notably higher than PC's (R118, a lower scale). Standard PC scratches easily from routine contact — keys, rings, cleaning cloths. Acrylic resists routine scratching without additional coatings. For retail display covers, optical lenses, and surfaces that receive frequent contact, acrylic's surface hardness reduces maintenance and extends service appearance. PC can be hard-coated, but that adds cost.
Chemical Environments and Solvent Wiping
Acrylic resists dilute acids, bases, and many cleaning solutions that attack polycarbonate. PC is attacked by acetone, methylene chloride, toluene, gasoline, and many other organic solvents — contact leaves crazed, cracked, or cloudy surfaces. In laboratory environments, food service, or any setting where cleaning agents include ketones or aromatics, acrylic is far more chemically appropriate.
Cost-Sensitive Applications
When impact resistance is not the governing design criterion, acrylic's 20–40% lower cost is a practical advantage. Large-format displays, retail shelving, and decorative partitions that need transparency but not toughness are commonly fabricated in acrylic to control project cost.
Specs Head-to-Head
Impact Resistance
The numbers are stark: polycarbonate has an impact strength of roughly 250× that of glass and 30× that of acrylic. Acrylic is brittle — it shatters cleanly under sufficient impact, generating sharp-edged fragments. Polycarbonate deforms and dents but typically does not shatter. In any safety or protection application, this difference is non-negotiable.
Optical Properties
Both materials are optically clear at appropriate thicknesses. Acrylic has better UV cut-off behavior in standard grades, blocking UV below ~380 nm while transmitting visible light at 92%. PC transmits at 88% and passes more near-UV unless specifically UV-stabilized. For UV-sensitive displays or archival applications, acrylic is the safer choice.
Thermal Behavior
PC's 240°F continuous rating is roughly 70°F above acrylic's. This gap matters in lighting covers near warm sources, automotive applications, and any industrial enclosure near heat-generating equipment. Both materials thermoform readily, but at different temperature ranges — acrylic typically requires higher forming temperatures (270–340°F) than PC.
Weathering and Aging
Standard cell-cast acrylic has excellent 10–20 year outdoor stability. PC yellows over time in UV unless stabilized; even UV-stabilized PC grades typically show more color shift over a 5–10 year outdoor service life than quality cast acrylic. For permanent outdoor installations, acrylic remains the preferred choice when optical clarity over time is specified.
Fabrication
Both materials cut with standard carbide tooling, laser-cut, cement-bond, and thermoform. Acrylic bonds with solvent cements more easily and produces cleaner cemented joints for display fabrication. PC requires different solvents and is more challenging to cement to a water-clear, stress-free joint. Both can be drilled and routed, though PC tends to be more forgiving of variation in cutting speed due to its toughness.
Cost & Availability
Acrylic sheet (cell-cast and continuous-cast) and extruded sheet are available from most plastic distributors in thicknesses from 0.060″ to 4″+. Polycarbonate sheet (Makrolon, Lexan, and equivalents) is similarly stocked. Acrylic prices run approximately $3–5/sq ft in standard thicknesses; PC runs $5–8/sq ft for equivalent gauges. Both materials are available in UV-stabilized and non-UV-stabilized grades; mirror, tinted, and textured versions are also stocked.
Common Alternatives
- PETG sheet — Impact resistance between acrylic and PC; easy thermoforming; better chemical resistance than PC. See polycarbonate vs PETG and acrylic vs PETG.
- Tempered glass — Higher clarity and scratch resistance than all plastics; significantly heavier and more breakage risk in fabrication.
Related Guides
More related guides
Explore related material decisions and where these plastics show up in real production:
Applications
Industries
Other comparisons
Spec sheets