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How do polyethylene terephthalate and polycarbonate differ in common uses?

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major industrial polymers Figure 1: The linear form of polyethylene, known as high-density polyethylene (HDPE).

Polyethylene terephthalate (PET) and polycarbonate (PC) are both members of the polyester family, but they differ significantly in their primary industrial and consumer applications due to their distinct physical properties.123

Polyethylene Terephthalate (PET)
PET is primarily valued for its strength, stiffness, and barrier properties. Its common uses include:
* Textiles: It is widely spun into fibers for permanent-press fabrics, often blended with cotton or wool to provide wrinkle resistance.24
* Packaging: It is blow-molded into transparent, rigid containers for carbonated beverages and food products.23
* Industrial Materials: PET is used in tire yarns, conveyor belts, seat belts, and nonwoven fabrics for drainage and medical applications.2
* Films: It is extruded into films (such as Mylar) used for photographic backing and recording tapes.24

Polycarbonate (PC)
PC is classified as an engineering plastic, prized for its exceptional impact resistance, optical clarity, and dimensional stability. Its common uses include:15
* Safety Equipment: Due to its high impact strength, it is used for safety glasses, safety shields, helmets, and face masks for sports.14
* Optical Media: Its transparency and flow properties make it ideal for injection-molding compact discs.13
* Structural Components: It is fabricated into shatterproof windows, large water carboys, and housings for appliances, automobiles, and aircraft.14