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Why is polymethyl methacrylate used for shatter-resistant windows and skylights?
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plastic
Plastic soft-drink bottles are commonly made of polyethylene terephthalate (PET).
Polymethyl methacrylate (PMMA) is used for shatter-resistant windows and skylights primarily because it is a tough, rigid, and transparent plastic that serves as an ideal substitute for glass.12
Its suitability for these applications is due to several key factors:
- Structural Properties: The presence of pendant methyl groups in the polymer structure prevents the chains from packing closely in a crystalline fashion or rotating freely, which results in a material that is both rigid and tough.12
- Optical Clarity: PMMA offers almost perfect transmission of visible light.1
- Durability: It retains its transparency and physical properties even after years of exposure to ultraviolet radiation and various weather conditions.12
Because of these characteristics, PMMA is frequently manufactured into sheets that can be thermoformed or machined for use in domed skylights, aircraft canopies, and other impact-resistant applications.12