1. Mechanooxidation of polyethylene (PH)
During Processing (screw extrusion)
•The mechanochemical reaction which results from shearing of the polymer chain is
typified in the above schematic.
•Hydroperoxides produced in the polymer at this stage subsequently sensitize the
fabricated product to further oxidation.
•The Willow Ridge catalytic additive reduces the energy necessary for further chain
scission.

2. Formation of low Mw carboxylic acids and esters in the oxidation of polyethylene
The Willow Ridge catalyst technology allows the free
radical products produced during processing to
transform into lower Mw carboxylic compounds
initiated by ambient heat, UV energy, and time.
This process can be monitored by the increasing
absorbance of the carbonyl (C=O) functional group
through FT-IR analysis, as well as Mw measurements
through HPSEC analysis.
The change in the chemical structure of the polymer
also changes the hydrophobicity, and as a result allows
for the polymer to be readily assimilated by
microorganisms once they come in contact with the
microbes.
However, the oxidation products are not extractable by
water or by a 0.1 N NaOH solution medium, which
relates to no migration issues for food contact
applications.

3. Summary of polymer oxidation
Oxidation involves three distinct phases; Initiation, Propagation, and Termination.
Initiation begins in the screw extruder with the introduction of hydroperoxides. Reaction (e) is the rate
determining step as the microbial biodegradation will follow the oxidation growth rate measured by
looking for the carbonyl groups formed in reaction (h).
The Willow Ridge technology lowers the activation energy necessary to promote complete oxidation and
serves as a vehicle to control a steady oxidative-degradation rate, which will convert into a steady
biodegradation rate once the material is properly disposed of and comes into contact with microbes.