04-01-2010, 03:03 PM
High impact styrene is a high grade styrene mix that's almost ABS. It's almost the same chemicals (acrylonitrile added with polybutadiene to toughen it) but with a heavier amount of polystyrene in the mix. When considering types of ABS, the stronger you want it, the lower the styrene content, and the higher the acrylonitrile content.However, ABS is like 50% styrene, sometimes more, sometimes less. It's just a strengthened version of styrene, specifically developed to be less brittle and withstand more "abuse."Pound for pound, ABS is definately a better material in all ways that it counts for masks, but it costs roughly twice as much.Paint it and UV protect it, and don't get it too cold when you flex it, or keep it in heat, and you'll be good. The older it gets, the less you want to flex it. That's true of non-UV-protected ABS too, but by comparison, it's like several years to get the same kind of issues with ABS that you can get in months from styrene. ABS is availible in UV-protected formulas as well.White styrene sheets usually come with a blue tint to the white. It's a paint added to the styrene mix for the sole purpose of attempting to hide the natural yellowing that styrene goes through as it breaks down, which can sometimes happen very quickly if care isn't taken with it.