What is ABS Plastic?
Acrylonitrile Butadiene Styrene (ABS) is an opaque thermoplastic and amorphous polymer. “Thermoplastic” (as opposed to “thermoset”) has to do with the way the material responds to heat. Thermoplastics become liquid (i.e. have a “glass transition”) at a certain temperature (221 degrees Fahrenheit in the case of ABS plastic). They can be heated to their melting point, cooled, and re-heated again without significant degradation. Instead of burning, thermoplastics like ABS liquefy which allows them to be easily injection molded and then subsequently recycled. By contrast, thermoset plastics can only be heated once (typically during the injection molding process). The first heating causes thermoset materials to set (similar to a 2-part epoxy), resulting in a chemical change that cannot be reversed. If you tried to heat a thermoset plastic to a high temperature a second time it would simply burn. This characteristic makes thermoset materials poor candidates for recycling. ABS is also an amorphous material meaning that it does not exhibit the ordered characteristics of crystalline solids.
How is ABS made?
ABS is most commonly polymerized through the process of emulsion (the mixture of multiple products that don’t typically combine into a single product). A well known example of an emulsified product is milk. ABS is also created, albeit less commonly, by a patented process known as continuous mass polymerization. Globally, the most common methodology to create ABS is the emulsion process.
It is important to note that because ABS is a thermoplastic material, it can be easily recycled as mentioned above. This means that a common way of producing ABS plastic is from other ABS plastic (i.e. making ABS from ABS).