[Home]History of Polyethene

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Revision 10 . . (edit) October 2, 2001 1:06 am by DavidSaff [spelling]
Revision 9 . . (edit) October 2, 2001 1:04 am by Sodium
Revision 7 . . September 29, 2001 2:48 am by Not now
  

Difference (from prior major revision) (minor diff, author diff)

Changed: 11c11
The angles are soewaht different than shown in ASCII.
The angles are somewhat different than shown in ASCII.

Added: 27a28,32
Types of polyethene

Their are two main types of polyethene: High Density Poly(ethene) (HDPE) and Low Density Poly(ethene) (LDPE). The main difference between these is the extent of branching? in the polymer chains. LDPE has many branches which means that the chains do not fit well together. It has therefore less strong intermolecular forces as the Instantaneous-dipole induced-dipole attraction is less. This results in a lower density and tensile strength. LDPE is created by free radical polymerization.

HDPE has virtually no branching and thus stronger intermolecular forces and tensile strength. The lack of branching is ensured by the the aid of a Zieglar-Natta catalyst, where the polymer chain actually grows out from the catalyst.

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