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Although thermal degradation is defined as an oxygen free process it is difficult in practise to completely exclude oxygen. Where this is the case thermal oxidation is to be expected, leading to the formation of free radicals by way of hydroperoxides. These may then participate in thermal degradation reactions, accelerating the rate of breakdown.
Furnaces used for diffusion and thermal oxidation at LAAS technological facility in Toulouse, France. In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer. The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it.
Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition.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. [1]
Processes in the thermal degradation of organic matter at atmospheric pressure.. Thermal decomposition, or thermolysis, is a chemical decomposition of a substance caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes.
The degradation chemistry is complicated due to simultaneous photodissociation (i.e. not involving oxygen) and photo-oxidation reactions of both the aromatic and aliphatic parts of the molecule. Chain scission is the dominant process, with chain branching and the formation of coloured impurities being less common.
Thermal aging tests assess the effects of prolonged exposure to elevated temperatures on a material's chemical and physical properties. High temperatures can accelerate oxidation, polymer degradation, and phase transitions, leading to reduced mechanical strength and altered performance characteristics.
The Cope reaction or Cope elimination, developed by Arthur C. Cope, is the elimination reaction of an N-oxide to an alkene and a hydroxylamine. [1] [2] [3] [4]Cope reaction ...
The thermal-oxidative degradation of a polymer starts at lower temperatures than the merely thermal degradation. Both types of degradation proceed via a radical mechanism. [8] Aromatics offer a good protection against both types of degradation, because free radicals can be delocalized through the π-system of the aromatic and stabilized. In ...