"Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition."
The various factors that can cause polymers to degrade, including environmental factors and exposure to heat or light.
Polymer structure: Understanding the molecular structure and properties of polymers, including chain length, molecular weight, branching, and tacticity.
Polymer types: Knowledge of various types of polymers such as thermoplastics, elastomers, thermosets, etc., their unique properties and applications.
Chemical and physical degradation: This covers chemical and physical mechanisms that can lead to polymer degradation, including thermal, photo-, oxidation, hydrolysis, and radiation degradation.
Polymer stabilization: Understanding the different methods to stabilize and protect polymers including the use of antioxidants or UV protectants.
Characterization techniques: Different analytical techniques that can be used to investigate changes that occur during polymer degradation including spectroscopy (IR, UV-Vis, NMR), chromatography, and microscopy.
Kinetics of degradation: Understanding the reaction kinetics that describe the rate of polymer degradation based on environmental factors such as temperature, sunlight intensity, and chemical composition.
Relationship between polymer structure and degradation: The effect of polymer structure and chemical composition on degradation rate.
Mechanisms of degradation: Understanding the different mechanisms that can cause polymer chain scission or crosslinking, such as free radical reactions or acid-catalyzed hydrolysis.
Environmental degradation of polymers: Understanding the degradation of polymers under environmental conditions, including biodegradation, composting, and landfills.
Polymer recycling: The process of recycling polymers including the types of recycling processes and the effect of degradation on recyclability.
Applications of polymer degradation: This covers the use of polymer degradation in automotive, aerospace, medical, and food industries.
Thermal degradation: It occurs when a polymer is subjected to high temperature. The chemical bonds in the polymer break down due to the heat, causing the polymer to degrade.
Photo-oxidation: The degradation process that happens when a polymer is exposed to UV light. The UV rays can cause the polymer to oxidize over time, which leads to its decomposition.
Hydrolysis: This type of degradation occurs when a polymer is broken down into simpler molecules by reacting with water. The water molecule cleaves the polymer chain, leading to the formation of new molecular species.
Chemical degradation: It is a process when a polymer is chemically broken down by a reactive species, such as an acid or alkali. The polymer's stability and structural integrity could be affected by the occurrence of such reactions.
Biological degradation: The breaking down of polymer chains caused by biological agents, such as bacteria or fungi. These agents release enzymes that degrade the polymer, leading to its ultimate breakdown.
Mechanical degradation: This type of polymer degradation refers to the physical breakdown of a polymer due to mechanical stresses. Mechanical deformation and abrasion can significantly impact polymer structure.
Thermal oxidation: The process of oxidative degradation induced by high temperatures. This happens due to the presence of atmospheric oxygen, which can lead to chemical reactions with the polymer, leading to a loss of mechanical properties.
Radiation Degradation: This occurs when a polymer is exposed to high-energy radiation like X-rays, gamma rays or electron beams. The polymer degradation happens due to radiation-induced reactions with molecular species present in the polymer.
Thermal hydrolysis: Disintegration of the polymer due to heat and water together. The combination of high temperature and humid environment leads to the cleavage of polymer bonds.
Thermal-mechanical degradation: Polymer degradation due to the simultaneous action of mechanical and thermal stresses. The degradation happens due to a combination of shear stress, high temperature, and prolonged exposure.
Thermal-oxidative-mechanical degradation: This occurs when all three stress factors - mechanical, thermal and oxidative stresses - combine to produce a profound degradation of polymers, leading to a breakdown.
Environmental Stress cracking (ESC): It is polymer degradation due to the simultaneous action of mechanical stress and agents such as chemicals, moisture, and temperature. The degradation is accelerated when the polymer is exposed to both stress conditions simultaneously.
"Polymers and particularly plastics are subject to degradation at all stages of their product life cycle, including during their initial processing, use, disposal into the environment, and recycling."
"Biodegradation can take decades..."
"...whereas some industrial processes can completely decompose a polymer in hours."
"Polymer stabilizers ensure plastic items are produced with the desired properties, extend their useful lifespans, and facilitate their recycling."
"Biodegradable additives accelerate the degradation of plastic waste by improving its biodegradability."
"Some forms of plastic recycling can involve the complete degradation of a polymer back into monomers or other chemicals."
"In general, the effects of heat, light, air, and water are the most significant factors in the degradation of plastic polymers."
"The major chemical changes are oxidation and chain scission..."
"These changes affect physical properties like strength, malleability, melt flow index, appearance, and color."
"The changes in properties are often termed 'aging'."
"Polymers and particularly plastics are subject to degradation..."
"Technologies have been developed to both inhibit or promote degradation."
"Polymer stabilizers ensure plastic items are produced with the desired properties..."
"...extend their useful lifespans..."
"...and facilitate their recycling."
"Biodegradable additives accelerate the degradation of plastic waste..."
"...the effects of heat, light, air, and water are the most significant factors in the degradation of plastic polymers."
"The major chemical changes are oxidation and chain scission..."
"These changes affect physical properties like strength, malleability, melt flow index, appearance, and color."