Types and Categories of Plastics

September 25, 2014
Types and Categories of Plastics

An expansive portfolio of plastics is on hand for today’s industrial applications. The tailored polymers exhibit properties that compete with metals and ceramics, ushering in the plastic age. The evolution of these plastics began at the dawn of the twentieth century, with industry in search of substitutes for elastic materials that lacked key characteristics, the capacity to withstand the extreme temperatures of the foundry and the caustic spills on oil rigs and gas refineries, but the formidable substance has since matured to include countless plastics. Each polymer is graded and adaptable, able to promote dominant characteristics and subdue undesired properties, bringing the best in elasticity or durability to industry.

Taking hold of these properties, we see that plastic falls into several fundamental domains. Thermosetting plastics are malleable before they harden, but once they do cure, they retain their shape and resist change. This class of polymer is tough and durable, currently the champion form of plastic for moulding components in many industrial fields. Car body parts are examples of a thermoset plastic, as are other components destined for use in harsh environments where elevated temperatures, abrasive forces, and corrosive chemicals are present.

So far we’ve seen a distinct separation between plastic. Thermoplastic is the next type of plastic that retains this simple contrast. Thermoplastic materials include nylon, polyvinyl chloride, and dozens of polymers based on weakly-linked molecular bonds. Consistent to this structure, these substances melt under high temperatures, and they’re easy to mold, unlike a thermosetting plastic, which can only be shaped once during an initial heat-formed manufacturing process. We then add elastomers to the mix, synthetic rubber substitutes that aren’t strictly a type of plastic, but we’d be remiss in not mentioning this highly pliable polymer and its properties, characteristics that can be adapted to include a rigid structure that compares to a standard plastic. And this is where the waters become murky. An elastomer can be conditioned to conform to the thermoplastic model or the thermoset definition. Think of today’s vehicle tyres and how they burn without deforming. The same dual properties exist within polyurethane, and we must conclude that it’s the production matrix of a plastic that defines the tailored properties, whether the substance forms a thermoset, a thermoplastic, or exhibits the pliable traits of an elastomer.

For further elucidation, refer to the above types of plastics, the categories set by organic chemists, and add further study by researching epoxies, silicones, and other polymer groups.