Nylon is a synthetic thermoplastic linear polyamide (a large molecule whose components are bound by a particular type of bond) that was first produced in 1935 by American chemist Wallace Carothers who was then working at the DuPont research facility in Delaware. Wallace produced what is technically known as Nylon 66 (still one of the most common variants). Demand for Nylon in particular and synthetic materials in general grew during World War II when natural items like silk, rubber, and latex were in significantly shorter supply.
Nylon is used for a variety of applications to include clothing, reinforcement in rubber material like car tires, for use as a rope or thread, and for a number of injection molded parts for vehicles and mechanicalequipment. It is exceptionally strong, relatively resistant to abrasions and moisture absorptivity, long lasting, resistant to chemicals, elastic and easy to wash. Nylon is often used as a substitute for low strength metals. It is the plastic of choice for components in the engine compartment of vehicles because of its strength, temperature resilience, and chemical compatibility.
Nylon can also be combined with a large variety of additives to produce different variants with significantly different material properties. Here is a look at a composite gear made of both Nylon and carbon.
Nylon is commonly referred to using the chemical designation “PA” (e.g. PA 6 or PA 6/66) and is most commonly available in black, white, and it’s natural color (off white or beige). Perhaps the most common variant for engineering applications is Nylon 6/6. Nylon 6/6 can be extruded (melted and forced through a nozzle) and is therefore a good plastic for both injection molding and 3D printing. It has a high melting temperature making it a wonderful substitute for metals in high temperature environments (e.g. under the hood in a vehicle). The material’s downside is that it has relatively low impact strength (even when compared to other plastics, see the chart below). The following diagram shows the relative impact strength of Nylon when compared to the impact strength of other commonly used plastics such as ABS, Polystyrene (PS), or Polycarbonate (PC). Of note, the impact strength of Nylon can actually be improved by a process called “conditioning.” For this reason as well as the ease with which Nylon can be combined with other materials to improve its strength, it is important to check the material properties of the specific Nylon composite you are using.