Question

High density polyethylene(HDPE) can be prepared from ethylene by

• A. Ziegler-Natta process
• B. Heating with peroxides
• C. Condensing in sealed tubes
• D. Condensing with styrenes

Answer 1

The correct option is A Ziegler-Natta process

HDPE is prepared by co-ordination polymerization which occurs through the intermediate formation of co-ordination complexes. For example, ethylene first forms a co-ordination complex with the transition metal titanium by donating its $\pi$ electrons. The $\pi$ complex thus formed then reacts stepwise with a large number of ethylene molecules ultimately leading to the formation of a polymer. The polythene so obtained has high density $\left(0.92g/c{m}^3\right)$ and higher m.pt. (403K) as compare to LDPE $(density-0.92g/c{m}^{3}andm.pt.384K)$