Acrylic vs. Polycarbonate: Comparing the Transparent Plastics

Transparent plastics have become vital alternatives to glass in a wide range of industries—from aerospace and architecture to product design and signage.

Among them, Acrylic (PMMA) and Polycarbonate (PC) stand out as the two most popular materials. Both offer excellent clarity, but their performance in terms of strength, durability, and processability differ significantly.

In this article, I’ll help you understand how acrylic and polycarbonate compare, and how to select the right one based on your specific project needs.

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What Are Acrylic and Polycarbonate?

Acrylic (PMMA)

Acrylic, often sold under brand names like Plexiglas or Lucite, is a transparent thermoplastic that resembles glass but is lighter and more shatter-resistant. It is composed of polymethyl methacrylate (PMMA) and is known for its high clarity and weatherability.

Key Features:

• Excellent optical clarity (up to 92% light transmission)
• High resistance to UV radiation
• Good scratch resistance
• Brittle under high impact
• Easy to fabricate and polish

Acrylic is commonly used in:

• Signage and displays
• Windows and skylights
• Aquariums
• Furniture and lighting covers

Polycarbonate (PC)

Polycarbonate is a much tougher plastic known for its incredible impact resistance and moderate flexibility. Commercial names include Lexan and Makrolon. It is formed through the polymerization of bisphenol A (BPA) and phosgene.

Key Features:

• High impact resistance (250 times stronger than glass)
• Lower light transmission (~88%)
• Excellent dimensional stability
• Prone to scratching without coating
• Performs well in both cold and hot environments

Polycarbonate is often used in:

• Machine guards and protective barriers
• Safety glasses and face shields
• Bulletproof windows
• Medical devices
• Aircraft components

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Strength, Clarity, and Impact Resistance Compared

Let’s break down how acrylic and polycarbonate compare across several physical properties.

Property	Acrylic (PMMA)	Polycarbonate (PC)
Light Transmission	~92%	~88%
Impact Resistance	6–7 times stronger than glass	250 times stronger than glass
Scratch Resistance	High	Low (needs hard coating)
UV Resistance	Excellent	Poor (unless UV-stabilized)
Weight	~1.19 g/cm³	~1.20 g/cm³
Heat Resistance	Up to ~80°C	Up to ~115°C
Flexibility	Low (brittle)	High (flexible)
Cost	Lower	Higher

Dive Deeper: What These Numbers Mean

While acrylic offers superior clarity and a glass-like appearance, it is more prone to cracking under load or impact. In contrast, polycarbonate can absorb and dissipate energy effectively, making it ideal for protective applications—but its surface scratches easily unless coated.

If your application involves static displays in safe environments, acrylic is often a better choice. For dynamic, high-risk, or safety-related environments, polycarbonate offers better performance and safety.

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What Are Acrylic and Polycarbonate?

Acrylic (PMMA)

Acrylic, often sold under brand names like Plexiglas¹ or Lucite, is a transparent thermoplastic that resembles glass but is lighter and more shatter-resistant. It is composed of polymethyl methacrylate (PMMA)² and is known for its high clarity and weatherability.

Key Features:

• Excellent optical clarity (up to 92% light transmission)
• High resistance to UV radiation
• Good scratch resistance
• Brittle under high impact
• Easy to fabricate and polish

Acrylic is commonly used in:

• Signage and displays
• Windows and skylights
• Aquariums
• Furniture and lighting covers

Polycarbonate (PC)

Polycarbonate is a much tougher plastic known for its incredible impact resistance³ and moderate flexibility. Commercial names include Lexan and Makrolon. It is formed through the polymerization of bisphenol A (BPA) and phosgene.

Key Features:

• High impact resistance (250 times stronger than glass)
• Lower light transmission (~88%)
• Excellent dimensional stability
• Prone to scratching without coating
• Performs well in both cold and hot environments

Polycarbonate is often used in:

• Machine guards and protective barriers
• Safety glasses and face shields
• Bulletproof windows
• Medical devices
• Aircraft components

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Which Plastic is Easier to Machine?

Acrylic

Acrylic is easy to cut, mill, drill, and polish. It behaves predictably during machining and creates clean, crisp edges. After machining, acrylic can be flame-polished or buffed to restore its optical clarity.

However, it’s more brittle, and poor fixturing or too much force can lead to cracks or chips.

Polycarbonate

Polycarbonate is more difficult to machine cleanly because of its tough, ductile nature⁴. It tends to gum up tooling and create burrs. However, it can be cold-formed or bent without cracking, which acrylic cannot do.

Tips for Machining Acrylic:

• Use sharp carbide tools with polished edges
• Avoid vibration to prevent cracking
• Use slow feed rates and low heat

Tips for Machining Polycarbonate:

• Use high-rake angle cutters
• Coolants are essential to avoid gumming
• Deburr carefully due to soft edges

Dive Deeper: Fabrication Techniques

• Bonding: Acrylic bonds well with solvents and adhesives. Polycarbonate may require special primers or mechanical fastening.
• Thermoforming: Both materials are thermoformable, but polycarbonate requires higher forming temperatures.
• Laser Cutting: Acrylic performs well with laser cutting, giving polished edges. Polycarbonate may discolor or emit toxic fumes when laser cut.

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Choosing the Right Transparent Plastic for Your Project

Choose Acrylic If:

• You need a crystal-clear finish
• The part will be displayed indoors or outdoors
• Scratch resistance and aesthetics are important
• The application is static, not subject to force or impact
• You want easy fabrication and bonding

Choose Polycarbonate If:

• The part must withstand high impact or stress
• It will be exposed to fluctuating temperatures
• It needs to bend without breaking
• It’s a safety-critical application (guards, shields)
• You can handle higher material costs

Dive Deeper: Cost vs. Performance

While polycarbonate costs more, its impact resistance and thermal stability⁵ can reduce the risk of product failure or injury—often justifying the price in industrial or safety-critical settings.

Acrylic offers lower upfront costs and better visual quality, making it a favorite in retail, art, and architecture.

Quick Summary

Feature	Acrylic	Polycarbonate
Clarity	Better	Slightly less
Impact Strength	Low	Very High
Scratch Resistance	High	Low (can scratch easily)
Machinability	Excellent	Fair
Outdoor Performance	Excellent	Requires UV protection
Cost	Lower	Higher

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Final Thoughts

Both acrylic and polycarbonate are clear, versatile plastics, but they serve different purposes depending on your application:

• Acrylic is for beauty and clarity
• Polycarbonate is for strength and safety

The best material for your project depends on your priorities. Think about:

• Will the part be outdoors or indoors?
• Will it face impact, heat, or bending?
• Do you need visual perfection or functional toughness?

Prototyping with both materials is a practical approach when performance trade-offs aren’t immediately clear. With the right plastic chosen, you’ll get better durability, aesthetics, and performance over the long term.