What are Thermoplastics?

Thermoplastics are a category of plastics that become soft and moldable upon heating and solidify upon cooling. This process is reversible and repeatable through repeated heating and cooling cycles, representing a physical change rather than a chemical one. These materials can dissolve in specific solvents, exhibiting both melt-processable and soluble characteristics.

Common thermoplastics include the four major types: polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), and polystyrene (PS), often referred to as general-purpose plastics. These typically have a continuous service temperature below 100°C. Thermoplastics are known for their excellent electrical insulation properties. Notably, polytetrafluoroethylene (PTFE), polystyrene (PS), polyethylene (PE), and polypropylene (PP) possess very low dielectric constants and loss factors, making them ideal for high-frequency and high-voltage insulation applications.

While thermoplastics offer advantages in processability and ease of molding, they generally exhibit lower heat resistance and are susceptible to creep—a time-dependent deformation under load. The extent of creep varies based on factors such as applied load, ambient temperature, exposure to solvents, and humidity levels.