Question

The difference in the densities of low density $(LDP)$ and high density polymers $(HDP)$ is due to the fact that

• A. $LDP$ are highly branched structures while $HDP$ consists of closely packed linear molecules
• B. $LDP$ are linear chains while $HDP$ are branched chains of polythene
• C. both $LDP$ and $HDP$ are unbranched linear chains with different lengths
• D. at high temperature, the density of polymer is reduce

Answer 1

Answer: (A)

LDP obtained through the free radical addition and H-atom abstraction has highly branched structure. Due to this branching, the density of LDP becomes low. Whereas HDP is obtained when addition polymerisation of ethene takes place in a hydrocarbon solvent in the presence of a catalyst such as triethylaluminium and titanium tetrachloride. It consists of linear molecules and has a high density due to close packing.