HOW clear? Optically clear, transparent, or translucent? What level of transmissibility (% of light transmitted) would be okay?
What pH and what temperatures?
The (partial) list below proceeds in a decreasing chemical resistance as you read down:
ECTFE can be had in translucent to near-transparent sheets. PFA is similarly clear, but don't know of anybody supplying it in sheet form. Both are pretty much as chemically resistant as you can get in a "clear" product at high temperatures.
PVC, ABS and similar vinyl compounds can achieve transparency, and have good acid/base resistance. Think of clear vinyl tubing. Both are limited to below-boiling temperatures.
Cellulose-based plastics (used for a lot of "blister" packaging) have "moderate" acid and base resistance, and good transparency. Temperature limits for these are pretty low ("warm water")
Polycarbonate and acrylic are commonly used as "window" substitutes; both have pretty lousy chemical resistance.
Does anyone know of a source of optical quality clear acrylic camera domes which truely are of optical quality? I need a size ranging between 14 and 16 inches in diameter. They would be hemispherical and significantly superior to typical security camera domes.
Thanx.
I agree glass is best. If you are fixed on plastic then try SAN. It's cheap, chemically resistant and transparent. And it has the highest modulus and therefore good scratch resistance compared to many other transparent polymers. For extra chemical resistance get a grade with higher acrylonitrile content.
You might look at cellulose acetate proprionate too (from Eastman). It's not that scratch resistant but has a special property that with a hair drier you can heat it and the scratches anneal out.
I really enjoyed your excellent answers to a broad range of topics.
You are right, there are many ways to measure scratch resistance and they give different answers. From working for several of years on that subject at a major appliance manufacturer I have some experience. In fact your comment is right on the mark, the two extremes give the best performance. Soft elastomeric materials like PU are excellent and so are very hard materials like diamond. Materials in between are poor, i.e. most plastics. Also it depends on what you make the scratch with and the type of test. However, if you cannot have diamond or PU then I have seen results for transparent plastics (made with Taber Abrader) and the material with highest modulus was best (SAN).
