{"id":25507,"date":"2026-10-27T02:32:42","date_gmt":"2026-10-27T02:32:42","guid":{"rendered":"https:\/\/hlled.com\/?p=25507"},"modified":"2026-10-27T03:58:39","modified_gmt":"2026-10-27T03:58:39","slug":"pc-vs-pmma-diffuser","status":"publish","type":"post","link":"https:\/\/hlled.com\/es\/choosing-guides\/pc-vs-pmma-diffuser\/","title":{"rendered":"PC vs PMMA Diffuser: Which to Choose for Your Project"},"content":{"rendered":"

Choose PMMA<\/strong> when the cover will be looked at and has to stay clear for years \u2014 architectural, retail, and anything with an optical job. Choose PC<\/strong> where impact and fire behavior matter more than optics: public spaces, low-level runs, transport. Choose silicone<\/strong> only when the cover has to bend.<\/p>\n\n\n\n

That is the short answer. The longer one matters because most comparison tables stop at a transmission figure and a “250 times stronger than glass” claim, neither of which decides the specification on its own.<\/p>\n\n\n\n

What actually differs between the two materials?<\/h2>\n\n\n\n

The numbers below are typical published values for extruded sheet and diffuser stock, not measurements from our own workshop. They vary by grade and by how much diffusing agent the maker loads into the resin, so treat them as a ranking rather than a specification.<\/p>\n\n\n\n

Property<\/th>PMMA (acrylic)<\/th>PC (polycarbonate)<\/th><\/tr><\/thead>
Light transmission<\/td>~92% (clear grade)<\/td>~85\u201389%<\/td><\/tr>
Impact resistance<\/td>Low \u2014 brittle, cracks under point load<\/td>High \u2014 roughly 250\u00d7 glass, ~30\u00d7 PMMA<\/td><\/tr>
Service temperature<\/td>~90 \u00b0C<\/td>~135 \u00b0C<\/td><\/tr>
UV stability<\/td>Naturally UV stable; resists yellowing for years<\/td>Needs UV stabilization to avoid yellowing<\/td><\/tr>
Fire behavior<\/td>HB \u2014 burns<\/td>UL94 V-2 to V-0 \u2014 self-extinguishing<\/td><\/tr>
Cold bending<\/td>Cracks; must be formed hot<\/td>Bends cold<\/td><\/tr>
Superficie<\/td>Harder, glossier, scratches show<\/td>Softer, easier to scuff<\/td><\/tr>
Typical use<\/td>Architectural, retail, optical<\/td>Public, outdoor, high-impact, industrial<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Two of those rows get quoted far more often than they get applied: impact resistance and UV.<\/p>\n\n\n\n

\"Ten
PC covers: clear, semi-clear, opal, opal matte and four prism-lens variants.<\/figcaption><\/figure>\n\n\n\n
\"Six
PMMA covers: clear, semi-clear, opal matte and three microprism variants.<\/figcaption><\/figure>\n\n\n\n

Why impact resistance matters less than the datasheet suggests<\/h2>\n\n\n\n

A cover sitting in an aluminum channel is not a free-standing panel. Its edges are captured by the two walls of the extrusion, the diffuser is supported along its full length, and the aluminum takes any load applied to the fixture. In a recessed or surface-mounted run, the cover is a lens, not a structural part.<\/p>\n\n\n\n

That changes the comparison. PC’s advantage is real and decisive in three situations:<\/p>\n\n\n\n