Table of Contents
What do you mean by degradation of polymerization?
Polymer degradation is a change in the properties of the polymer, such tensile strength, color, shape, and molecular weight, or of a polymer-based product under the influence of one or more environmental factors, such as heat, light, chemicals, or any other applied force.
What is chain end degradation?
Firstly the degradation start from chain end and resulting successive release of monomer unit. This phenomenon is actually reverse of propagation steps. So this type of degradation called de-polymerization. The molecular weight of the polymer decrease slowly.
What is degradation temperature?
4 Thermal Degradation. Thermal degradation occurs when the polymer changes its properties under the influence of increased temperature. Initially, it causes the migration of low-molecular-weight additives in aging materials, if any are present.
How the plastic degradation happen?
There are four mechanisms by which plastics degrade in the environment: photodegradation, thermooxidative degradation, hydrolytic degradation and biodegradation by microorganisms [33]. However, this entire process is very slow, and it can take 50 or more years for plastic to fully degrade [35].
What is chain end and random degradation?
In the case of chain-end scission, monomers are released. This process is known as unzipping, depropagation or end-chain depolymerization. Random main chain scission, on the other hand, leads to the formation of both monomers and oligomers (short chains with ten or fewer monomers).
What is mechanical degradation?
Mechanical degradation describes the breakdown of molecules in the high flow rate region close to a well as a result of high mechanical stresses on the macromolecules. This short-term effect is important only in the reservoir near the wellbore (and also in some of the polymer handling equipment, in chokes, and so on).
What is plastic degradation?
2. Degradation of plastics. Any physical or chemical change in polymer as a result of environmental factors, such as light, heat, moisture, chemical conditions or biological activity.
What is degradation reaction?
From Wikipedia, the free encyclopedia. Degradation reactions reduce the number of atoms in a molecule through a specific type of chemical transformation.
What does degradation mean in geography?
Physical Geography. the wearing down of the land by the erosive action of water, wind, or ice.
What is an example of degrading?
The definition of degrading is something that causes damage, humiliation or a loss of respect. When someone puts you down all the time and causes you to feel humiliated and disrespected, this is an example of degrading treatment.
What are the reactions in the random degradation reaction?
The random degradation reaction involves hydrolysis by trace amounts of water, oxidative degradation, cis -elimination, and inter- and intramolecular transesterification reactions [26].
Which is an example of the degradation of the environment?
Environmental degradation is the deterioration of the environment through depletion of resources such as quality of air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. It is defined as any change or disturbance to the environment perceived to be deleterious or undesirable.
The process of ‘degradation’ describes the chain scission process during which polymer chains are cleaved to form oligomers and finally to form monomers. ‘Erosion’ designates the loss of material owing to monomers and oligomers leaving the polymer 15.
How does the propagation of thermal degradation occur?
Propagation. The propagation of thermal degradation can involve a variety of reactions and one of these is where the free radical (R•) reacts with an oxygen (O 2) molecule to form a peroxy radical (ROO•) which can then remove a hydrogen atom from another polymer chain to form a hydroperoxide (ROOH) and so regenerate the free radical (R•).