Production method 3 - LLDPE

Although LLDPE has similar applications to LDPE, its manufacture is more like HDPE. The same reactors can in fact often be used for both. The main difference is that a co-monomer (second monomer) is used with ethene in order to introduce some degree of controlled branching of the polymer chains.

co-monomers used to make LLDPE
co-monomers used to make LLDPE co-monomers used to make LLDPE
co-monomers used to make LLDPE
co-monomers used to make LLDPE
co-monomers used to make LLDPE
co-monomers used to make LLDPE


Mechanism

Unlike LDPE, the reaction is not a free radical polymerisation. The catalysts used are very efficient, and 1g of catalyst can produce as much as 1000 kg of LLDPE. These very small amounts of catalyst remain in the polymer, and are not recovered.

The mechanism is essentially the same as that for HDPE , and the same reactors can often be used for both.

diagram: mechanism of Ziegler-Natta catalyst with LLPDE

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