Wednesday, 28 February 2018

Rubber Degradation and Antioxidants

Rubber is an elastomer type polymer, this means that once stretched or deformed, rubber can return to its natural shape.


A monomer is a small molecule of an organic substance. Between each individual molecule, there is a weak double bond. A monomer can also be defined as is a molecule that binds chemically to other molecules to form a supramolecular polymer. When large numbers of monomer units combine to form polymers, this process is called polymerization. (Source: 1.)

Polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. (Source 2.)

Polymer Degradation

During the polymerization process, the formation of free radicals (R) is initiated. This is thought of as the initial stage of the degradation process.

The second stage is called 'Propagation'. During this stage, the atmospheric oxygen reacts with free radicals (R) to create 'Peroxy' (ROO) radicals.

When comparing the propagation stage to the initiation stage, the degradation process during the propagation stage is much more rapid. This reaction is called an autocatalytic oxidation reaction and will progress continually until termination takes place by forming a stable product.

Once Peroxy radicals have been formed, these react further with the labile Hydrogen atom of the polymer which in turn forms unstable hydroperoxides (ROOH).

Now that hydroperoxides have been created, they will immediately decompose via homolytic cleavage to then form alkoxy and hydroxyl radicals. These radicals then further propagate the degradation mechanism.

Polymer Oxidation

Polymer oxidation is a very complex process but can briefly be described as the effect that oxygen has during the polymerization process.

Oxidation can be the cause of chain scission and cross-linking, this, in turn, may lead to the loss of elastic properties in your product.

Polymer Oxidation can be avoided by using rubber antioxidants. To find rubber antioxidants at a reasonable price, make sure to visit Prisma Rubber Additives today!



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