What is meant by chain scission?
A degradation mechanism (300–500°C) involving rupturing of bonds in the backboned of the polymer chain, while non-chain scission is concerned with all other bond-breaking reactions caused by pyrolysis. …
What is the most common cause of chain scission in PA 6?
Normally, chain scission is caused by exposure to elevated temperatures in combination with high shear stress, and is often associated with processing techniques where air is not present.
How do you degrade polyethylene?
Degradation of polyethylene can be classified as abiotic or biotic, the former being defined as deterioration caused by environmental factors such as temperature, UV irradiation, while the latter is defined as biodegradation caused by the action of microorganisms that modify and consume the polymer leading to changes …
What are the chains that make plastic?
polymer A substance made from long chains of repeating groups of atoms. Manufactured polymers include nylon, polyvinyl chloride (better known as PVC) and many types of plastics.
How does chain scission reduce molecular weight of a polymer?
Chain scission reduces the molecular weight of the macromolecules of a polymer and this finds some commercial applications in problems concerned with molecular weight control, particularly useful in the reclamation of polymer wastes. BenzartiK. , ColinX. , in Advanced Fibre-Reinforced Polymer (FRP) Composites for Structural Applications, 2013
Where do chain Scissions occur in FRP composites?
BenzartiK. , ColinX. , in Advanced Fibre-Reinforced Polymer (FRP) Composites for Structural Applications, 2013 Chain scissions can occur at peculiar sites of high reactivity (selective chain scissions). They may also be randomly distributed if all the repeat units are equi-reactive (random chain scissions).
What is the term used to describe chain scission?
Mechanicochemical degradation is the term used in describing chain scission of polymer backbones through the application of shear during a processing operation. It was previously believed that this type of process led to carbon-carbon chain scission, which usually causes a dramatic change in rheological properties.
Where does chain scission occur during photooxidation?
During photooxidation, the oxidation occurs in the vicinity of the double bond, resulting in chain scission.254 On the other hand, the crosslinking reactions occur under aerobic and anaerobic conditions.
