What happens to thermoplastics when they are heated?

When thermoplastics are heated, they exhibit a unique characteristic that allows them to be reshaped. Thermoplastics soften upon heating and can be molded into different shapes. This property is due to the molecular structure of thermoplastics, which consists of long chains of polymers that can slide past one another when the material is heated. As a result, when thermoplastics are subjected to heat, they do not undergo a chemical change; instead, they reach a pliable state where they can easily be formed into various shapes or structures. Upon cooling, they return to a solid state without losing their chemical identity. This ability to be reformed multiple times without significant degradation is what makes thermoplastics versatile materials in manufacturing and design.

The behavior of thermoplastics contrasts with other materials, such as thermosets, which become rigid and cannot be reshaped after the initial setting process. Thus, the reshaping capability of thermoplastics when heated is a defining feature that is crucial for various applications in engineering and product development.