Comparison Of Acrylic With Other Materials - We can compare acrylic with other materials on the following grounds. Polystyrene is the closest clear-plastic competitor in optical properties, but its performance at lower light wavelengths does not rival that of acrylic. It begins to absorb light at about three hundred and fifty nanometers and, consequently, does not transmit it. Same is the property of acrylic. Polycarbonate is a key material in the medical device area and is normally not used for diagnostic equipment when maximum clarity is a requirement. When taking about non diagnostic applications, acrylic competes with other clear plastics. These plastics include polystyrene, styrene acrylonitrile (SAN), polyvinyl chloride (PVC), polyethylene terephthalate glycol (PETG), and clear acrylonitrile butadiene styrene (ABS). Each of this material has its own advantages and disadvantages, depending on the application.
Polycarbonate material is clearly dominant when strength and toughness are the prime requirements as it tends to be over specified, especially for large parts whose failure in a medical environment could have severe consequences. While styrene copolymers are starting to gain on polycarbonate because of their toughness, clarity, and moderate pricing. On the downside, they are fairly soft and easily scratched. Chemical resistance offered by acrylic is much better than polycarbonate. When talking of impact resistance and strength, polycarbonate is tougher, although impact-modified acrylic grades can be used in many applications that specify polycarbonate. Acrylic is better than polycarbonate in terms of clarity, scratch resistance, and ultra violet transmission, and generally offers better process ability, since polycarbonate is prone to problems related to molded-in stress, such as crazing and cracking. When compared to ABS and clear PETG, ABS is less susceptible to residual molding stresses than polycarbonate, while PETG is less susceptible to chemical attack. But neither ABS nor PETG provides the clarity, scratch resistance, or light transmission of acrylic, and PETG is more difficult to process, tending to warp under adverse molding conditions.
Poly vinyl carbonyl is often selected when a flexible material is required, although it does not provide the clarity or scratch resistance of acrylic. Other competitors of acrylic in the medical market are polystyrene and styrene-containing copolymers such as SAN. These styrene materials exhibit low melt viscosity and are easy to process, but cannot quite match the performance of acrylic in the areas of clarity and UV transmittance. Polystyrene is used typically for complex parts because of its excellent process ability, which reduces the molded-in stresses that can affect light transmission in very complex parts. Failure of plastic parts is often traced to be mistakes in design, production methods, or material choice. When selecting the material for a particular application involves careful consideration of the end-use environmental conditions and functional requirements of the part.
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