Linear low-density polyethylene is made by the co-polymerisation of Ethylene using olefins with longer chains. This polymer is different from LDPE because it has short branches rather than long ones, processed at lower temperatures and pressures, and different molecular weight distribution and linear structure. In addition, its higher tensile strength and impact resistance (when compared to LDPE) allows it to be processed to thinner films with higher stress cracking resistance. The only disadvantage it has is its narrow heat resistance and its difficulty in processing.
The manufacturing process is similar to that of LDPE using the Ziegler-Natta catalyst, but an additional raw material, 1-butene or 1-hexene is added to the feedstock. This results in the formation of small side chains of one or two carbon atoms. The structure of the polymer is linear, but the density is lower due to the presence of such short branches and gives more shear strength and flexibility.
LLDPE is used for making thin film liners, wrapping film, stretching film, etc. 80% of the world’s productions goes to food packaging due to its high puncture resistance, thus increasing the food’s shelf life. It is also used in extrusion coating applications where it protects the object like containers, paper, etc.
It is used as insulating materials for cables.