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Abstract Viscoelastic models of polymer behaviour incorporate a relaxation time which is defined as the ratio of the viscosity of the elements to their modulus (see the article on polymer models).In more complex models a relaxation time spectrum is defined since it is recognised that an adequate model of the behaviour cannot be made using a single relaxation time. The agreement between experimental observations and theory increases as the number of elements, and associated relaxation times, in the models increase and by using a large number of elements and a relaxation time spectrum good agreement can he achieved. However this is an artificial process and the use of such models tells us nothing about the molecular processes which give rise to viscoelastic response, they merely provide a means by which the response of the polymer, over the temperature, time and strain rate for which the model is valid, can be predicted. There are however ‘genuine’ relaxations which occur in polymers which are related to the movements of side groups and give rise to changes in the modulus and loss tangent.
Abstract Viscoelastic models of polymer behaviour incorporate a relaxation time which is defined as the ratio of the viscosity of the elements to their modulus (see the article on polymer models).In more complex models a relaxation time spectrum is defined since it is recognised that an adequate model of the behaviour cannot be made using a single relaxation time. The agreement between experimental observations and theory increases as the number of elements, and associated relaxation times, in the models increase and by using a large number of elements and a relaxation time spectrum good agreement can he achieved. However this is an artificial process and the use of such models tells us nothing about the molecular processes which give rise to viscoelastic response, they merely provide a means by which the response of the polymer, over the temperature, time and strain rate for which the model is valid, can be predicted. There are however ‘genuine’ relaxations which occur in polymers which are related to the movements of side groups and give rise to changes in the modulus and loss tangent.
Relaxations in Polymers
Swallowe, G. M. (author)
1999-01-01
4 pages
Article/Chapter (Book)
Electronic Resource
English
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