Polyethylene (PE) is the most commonly used plastic material in the world, derived from the polymerization of ethylene gas. As a thermoplastic polymer, it can be melted and remolded multiple times, making it highly versatile across industries. Depending on its density and branching, polyethylene is classified into LDPE (Low-Density Polyethylene), HDPE (High-Density Polyethylene), and LLDPE (Linear Low-Density Polyethylene). HDPE is strong, rigid, and used in pipes, containers, and household products, while LDPE is softer and more flexible, ideal for films, bags, and packaging. Known for its excellent chemical resistance, polyethylene does not react with most acids, bases, and solvents, and it provides excellent moisture resistance, making it perfect for food packaging. It is also a good electrical insulator and is widely used in cable coatings. Its melting point ranges between 115°C and 135°C depending on the grade, allowing for easy molding and extrusion. However, being non-biodegradable, polyethylene poses environmental challenges, though it is recyclable and coded under #2 and #4 plastics. With its wide range of applications from toys and bottles to pipes and industrial films, polyethylene remains an indispensable material in modern life, balancing durability, affordability, and functionality.