nC2H4

nC2H4 refers to a polymer composed of repeating ethylene (C2H4) monomer units. This substance is more commonly known as polyethylene. Polyethylene is a thermoplastic polymer, meaning it can be melted and reshaped multiple times. Its properties vary significantly depending on how the ethylene monomers are linked together, primarily influenced by the polymerization process.

The two most common forms are low-density polyethylene (LDPE) and high-density polyethylene (HDPE). LDPE is characterized by branched polymer chains, resulting in a flexible and transparent material. It is widely used in plastic bags, films, and squeeze bottles. HDPE, on the other hand, has linear polymer chains with minimal branching, leading to a more rigid, strong, and opaque material. HDPE finds applications in milk jugs, detergent bottles, pipes, and toys.

Polyethylene is synthesized through various polymerization techniques, including free-radical, Ziegler-Natta, and metallocene catalysis. The choice of catalyst and reaction conditions dictates the degree of branching and molecular weight, thereby controlling the material's physical and mechanical properties. Polyethylene is one of the most produced plastics globally due to its versatility, low cost, and desirable properties such as chemical resistance and electrical insulation.