Plastic is a man-made or semi-manufactured substance primarily sourced from petrochemicals or organic materials such as cellulose and starch. The fundamental elements undergo chemical treatment to create extensive molecular chains known as polymers. These polymers can be shaped into diverse forms through methods including injection molding, extrusion, or blow molding. Certain types of plastics are also referred to as resins.

Plastic has become a prevalent material in contemporary society owing to its resilience, affordability, and ease of production. There exists a wide variety of plastics, each possessing distinct properties and features. Among the most frequently encountered types are polyethylene, polypropylene, PVC, PET, polystyrene, and nylon. Plastics can be categorized into two principal groups based on their chemical structure: thermoplastics and thermosets. Thermoplastics can be reshaped, melted, and remolded multiple times, while thermosets cannot be reprocessed upon heating.