Invented in 1953, Lexan continues to be a popular and useful plastic. Lexan is actually the brand name for a thermoplastic called polycarbonate. Lexan is often used in helmets (including those used by NASA astronauts), automotive windshields and bulletproof windows. Because Lexan is the name-brand version of polycarbonate, it can be expensive. If you are looking for a clear material with similar properties as Lexan, there are several alternatives you might consider.
Acrylic Glass
Acrylic glass is a common alternative to polycarbonates such as Lexan. Acrylic is not actually a glass—it is a thermoplastic like polycarbonate. The chemical name for acrylic is Poly(methyl methacrylate), often shortened to PMMA. Developed in 1928, acrylic is cheaper, shatter resistant and does not use the carcinogenic chemical bisphenol-A. Acrylic is also extremely easy to mold and shape. Acrylic is not quite as strong as Lexan but is often sufficient for all but the most demanding applications.
Ultra High Molecular Weight Polyethylene
Ultra high molecular weight polyethylene is another alternative to Lexan. Everyone is familiar with polyethylene products because plastic grocery bags are made from this material. Ultra high molecular weight polyethylene is a denser version of the plastic bag variety, resulting in a very sturdy thermoplastic. Ultra high molecular weight polyethylene has been used in the medical community for implants. There also exist several bullet-proof vest manufacturers that prefer ultra high molecular weight polyethylene.
Tempered Glass
Tempered glass, also known as toughened glass, is an alternative to Lexan in many applications. Unlike Lexan, acrylic and polyethylene, tempered glass is not a thermoplastic. Tempered glass is created by taking regular glass and treating it with special heat and compression techniques. Some tempered glass is also made through the use of chemicals. This treatment process produces a glass that is strong, resistant to shattering and very durable.