What is the structural difference between and ? How does the structure account for different behaviour and nature, hence the use of a polymer?
or Low-density polythene has a highly branched molecular structure. It has low density (0.92 g/cm 3) and low melting point, as the molecules do not pack well due to branching. It is transparent and chemically inert with moderate toughness.
or High-density polythene has linear chains, and thus the molecules are closely packed in space. Therefore, it has a higher density and melting point. In comparison to , it is harder, tougher and has greater tensile strength.