Thermal degradation of polymers is molecular deterioration as a result of overheating at high temperatures the components of the long chain backbone of the polymer can begin to be broken (chain scission) and react with one another to change the properties of the polymer. Almost 50% of failures of engineering plastics result from environmental degradation the increasing utilisation of plastics in more exacting applications and the pressure for increased life, without uneconomic over design, are imposing a requirement for improved characterisation of the performance. Degradation of plastic polymers can proceed by either abiotic or biotic pathways 17 generally abiotic degradation precedes biodegradation, and is initiated thermally, hydrolytically, or by uv-light in the environment 14 smaller polymer fragments formed by abiotic degradation can pass through cellular membranes and are biodegraded within the.
This degradation is usually negligible at ambient temperatures, but in some polymers it may be a problem during processing one important example is a condensation polymer such as nylon 66. Polymer degradation is a change in the properties tensile strength, colour, shape, etc polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalis and some salts. Introduction polymer degradation and stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology.
Polymer degradation and stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and. Polymer degradation and stability 98 (2013) 2801e2812 this paper is to discuss the most recent works reported the me- chanical and chemical recycling of some traditional polymers and. A method of degrading a polymer into oligomers and/or monomers in a solvent, using a catalyst, and a functionalized magnetic particle comprising a catalyst being capable of degrading the polymer into. Abstract this report is concerned with three distinct aspects of polymer degradation and stability with the general aim of the production of materials of improved. Polymer degradation in literature, poly(n-vinyl pyrrolidone) blended with pvc, pvp act as hcl absorber which decrease the thermal stability of pvc via increasing the dehydrochlorination rate.
Polymer degradation can be caused by heat (thermal degradation), light (photodegradation), ionizing radiation (radio degradation), mechanical action, or by fungi, bacteria, yeasts, algae, and their enzymes (biodegradation. Gpc/sec analysis of polymer degradation molecular weight molecular structure molecular size introduction understanding the effects of processing a polymer on its molecular weight, molecular weight distribution, and solution viscosity are important to manufacturers. -an ester bond next to a thioether group is much more susceptible to degradation than an unmodified ester -app: drug delivery, tissue engineering -degradation rates controlled by altering charge of neighboring groups or length of sulfide containing linker.
Read the latest articles of polymer degradation and stability at sciencedirectcom, elsevier’s leading platform of peer-reviewed scholarly literature. The degradation of plastics can be said to begin as soon as the polymer is synthesised, and is increased by residual stresses left by moulding processes this can be followed by exposure to light (especially uv), humidity, oxygen, heat, bacteria and stress. Polymer degradation is a change in the properties (tensile strength, color, shape, etc) of a polymer or polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkali and some salts.
Polymers degrade by several different mechanisms, depending on structure and exposure conditions degradation results from an irreversible change which leads eventually to failure the most common types of degradation occur through chemical reactions, but there are a few important examples of. In general, the degradation mechanisms experienced by polymers are free-radical processes initiated by bond dissociation at the pyrolysis temperature the specific pathway followed by a particular polymer is related to the relative strength of the. Thermal and oxidative degradation of polymers in recent decades synthetic polymeric materials, be-cause of their unique physical properties, have rapidly.