Amorphous plastic is a type of plastic that has a non-crystalline or disordered molecular structure. Unlike semi-crystalline plastics, which have both crystalline and amorphous regions, amorphous plastics have a completely random arrangement of polymer chains. This results in a material with unique properties that differ from those of semi-crystalline plastics.

Amorphous plastics are typically characterized by their transparency, high impact resistance, and ability to be molded into complex shapes with good dimensional stability. They also have a lower melting point and lower stiffness compared to semi-crystalline plastics.

Examples of amorphous plastics include polycarbonate (PC), poly(methyl methacrylate) (PMMA or acrylic), polystyrene (PS), and acrylonitrile-butadiene-styrene (ABS). These materials are commonly used in a variety of applications, such as automotive components, consumer products, medical devices, and electronic enclosures.

The unique properties of amorphous plastics make them well-suited for many different applications, but can also present challenges in processing and manufacturing. For example, amorphous plastics can be easier to weld than semi-crystalline plastics, as their lower melting point and lack of crystalline structure can makes it easier to achieve strong, consistent welds. Ultrasonic welding cis a great method for joining amorphous plastics.