Which polymer processing technique can be used to shape thermoplastics?

Extrusion is a widely used polymer processing technique specifically suited for shaping thermoplastics. During the extrusion process, thermoplastic materials are melted and continuously forced through a die to create long shapes such as sheets, tubes, or profiles. This method is highly efficient for producing consistent cross-sectional profiles and can be used to create various products, from packaging films to complex components in automotive and construction applications.

Thermoplastics, characterized by their ability to be re-melted and re-shaped, make extrusion particularly advantageous as it allows for continuous production and recycling of materials, which is not typically possible with other processes that involve irreversible changes to the material structure. Therefore, extruded products can be easily reprocessed, leading to less waste and greater sustainability in manufacturing.

The other options pertain to different processing methods that may not adequately apply to thermoplastics: welding is generally associated with joining materials rather than shaping them, sintering is a technique used primarily with powders (like ceramics or some composites) rather than thermoplastics, and fabrication can refer to a broad range of methods for making products but is not specific to shaping thermoplastics. Thus, extrusion stands out as the appropriate choice for shaping thermoplastics.