Low density polythene and high-density polythene, both are polymers of ethane but there is marked difference in their properties. Explain.
Low density and high-density polythenes are obtained under different conditions. These differ in their structural features.
Low-density polythene is highly branched structures.
LDP is obtained by free radicle addition reaction at high pressure and high temperature. It is chemically inert and tough but slightly flexible.
High-density polythene consists of closely packed linear molecules. Close packing increases the density.
HDP is obtained by the addition polymerization of the ethene in the presence of the hydrocarbon solvent at low pressure and temperature up to 350 K in the presence of a catalyst called Ziegler-Natta catalyst. Under these conditions, the polymer obtained is highly tough and has a high density due to close packing.
HDP is harder and tougher than LDP.