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Alan Wheeler · 12-12-2007, 23:04

I am not sure I would consider Polycarbonate (Lexon is a trade name) as inferior for use in windows. It is certainly very more resilliant to impact. But yes it has a surface that very easily scratches. However, so has PMMA or Acrylic sheet (Perspex and plexiglass are tradenames). Except Acrylic is usually coated with a special coating that makes it much more resiliant to scratching.
Both materials are thermoplastics. This means they both have a melting point. Acrylic is approx. 140DegC and Polycarbonate is aprox. 270DegC.
One big difference between the two is what light they filter. Polycarbonate is better at transmitting visual light. In other words, it seems more transparent. However, it blocks a great deal of the UV spectrum.
Acrylic is not so transparent, however, it transmits most of the UV spectrum. The result is that the Acrylic is actually better at resisting UV damage. PMMA's are more susceptable and can end up actually being less resistant to impacts than Acrylic in as little as 12months.
Here's an interesting fact. All the family of thermoplastics are made from oil. It takes about 2Kg of Oil to produce 1Kg of Acrylic. If you heat Acrylic enough, it will ignite at 460DegC. That's very hot. But as it burns, it produces nothing more than Co2 and water.

12-12-2007, 23:04	#9
Alan Wheeler Registered User Join Date: Dec 2003 Location: Marlborough Sounds. New Zealand Boat: Hartley Tahitian 45ft. Leisure Lady Posts: 8,042	I am not sure I would consider Polycarbonate (Lexon is a trade name) as inferior for use in windows. It is certainly very more resilliant to impact. But yes it has a surface that very easily scratches. However, so has PMMA or Acrylic sheet (Perspex and plexiglass are tradenames). Except Acrylic is usually coated with a special coating that makes it much more resiliant to scratching. Both materials are thermoplastics. This means they both have a melting point. Acrylic is approx. 140DegC and Polycarbonate is aprox. 270DegC. One big difference between the two is what light they filter. Polycarbonate is better at transmitting visual light. In other words, it seems more transparent. However, it blocks a great deal of the UV spectrum. Acrylic is not so transparent, however, it transmits most of the UV spectrum. The result is that the Acrylic is actually better at resisting UV damage. PMMA's are more susceptable and can end up actually being less resistant to impacts than Acrylic in as little as 12months. Here's an interesting fact. All the family of thermoplastics are made from oil. It takes about 2Kg of Oil to produce 1Kg of Acrylic. If you heat Acrylic enough, it will ignite at 460DegC. That's very hot. But as it burns, it produces nothing more than Co2 and water. __________________ Wheels For God so loved the world..........He didn't send a committee.