Today's KNOWLEDGE Share
Polymer Degradation
Polymer degradation refers to the process by which polymer materials undergo structural changes, resulting in the loss of their properties and functionality. This degradation can be physical, chemical, or biological, and it impacts the mechanical, thermal, and optical properties of the polymer.
II. Types of Polymer Degradation
1. Thermal Degradation
Thermal degradation occurs when polymers are exposed to high temperatures, causing the breakdown of molecular bonds. This type of degradation is common during processing and manufacturing.
2. Photo-Degradation
Photo-degradation is induced by exposure to ultraviolet (UV) radiation from sunlight. UV light can break down the chemical bonds in polymers, leading to discoloration, brittleness, and loss of mechanical strength.
3. Oxidative Degradation
Oxidative degradation involves the reaction of polymers with oxygen. This process is accelerated by heat and light and results in the formation of free radicals, which further propagate degradation.
4. Hydrolytic Degradation
Hydrolytic degradation is caused by the reaction of polymers with water. This type of degradation is significant in polymers that are used in humid or aquatic environments.
5. Biodegradation
Biodegradation involves the breakdown of polymers by microorganisms. While this can be advantageous for biodegradable plastics, it poses a challenge for conventional plastics that are not designed to degrade in the environment.
III. Factors Influencing Polymer Degradation
Several factors influence the rate and extent of #polymerdegradation:
Temperature: Higher temperatures accelerate the degradation process.
Light Exposure: Prolonged exposure to UV light increases the rate of photo-degradation.
Oxygen: The presence of oxygen facilitates oxidative degradation.
Moisture: Water can promote hydrolytic degradation.
Mechanical Stress: Physical stresses can create micro-cracks, which act as initiation sites for degradation.
Chemical Environment: Exposure to chemicals, such as acids and bases, can catalyze degradation reactions.
source : Plastics Technology
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