On the physics required for prediction of long term performance of polymers and their composites

McKenna, Gregory B.

doi:10.6028/jres.099.014

Cited by 108 publications

(60 citation statements)

References 39 publications

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“…In traditional glass science the concept of "fictive temperature" is used as a structural characteristic that by definition gives the temperature at which the structure would be in equilibrium [54][55][56][57][58][59]. For any aging experiment, in glass science one assumes that the fictive temperature adjusts itself monotonically from the initial temperature to the final temperature.…”

Section: Fictive Temperature Variations Following a Temperature Jumpmentioning

confidence: 99%

Strongly correlating liquids and their isomorphs

Pedersen

Gnan

Bailey

et al. 2011

Journal of Non-Crystalline Solids

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This paper summarizes the properties of strongly correlating liquids, i.e., liquids with strong correlations between virial and potential energy equilibrium fluctuations at constant volume. We proceed to focus on the experimental predictions for strongly correlating glass-forming liquids. These predictions include i) density scaling, ii) isochronal superposition, iii) that there is a single function from which all frequency-dependent viscoelastic response functions may be calculated, iv) that strongly correlating liquids are approximately single-parameter liquids with close to unity PrigogineDefay ratio, and v) that the fictive temperature initially decreases for an isobaric temperature up jump. The "isomorph filter", which allows one to test for universality of theories for the nonArrhenius temperature dependence of the relaxation time, is also briefly discussed.

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Section: Fictive Temperature Variations Following a Temperature Jumpmentioning

confidence: 99%

Strongly correlating liquids and their isomorphs

Pedersen

Gnan

Bailey

et al. 2011

Journal of Non-Crystalline Solids

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“…It is generally accepted that the main properties of physical ageing, also called structural relaxation, are non-linearity and non-exponentiality [20][21][22]. The nonlinearity is revealed by the asymmetry of the approach to equilibrium.…”

Section: General Featuresmentioning

confidence: 99%

“…Still related to the dynamics below T g , but near this temperature, large-scale mobility can occur besides the local mobility described in the previous section. This process, designated as physical ageing or structural relaxation [20][21][22], is related to the metastable glassy phase. The most common situation in which physical ageing is studied is when a material is cooled from above its T g to an ageing temperature, T a , below T g .…”

Section: General Featuresmentioning

confidence: 99%

Molecular dynamics in polymeric systems

2004

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It is well known that the properties of polymeric materials depend strongly upon their chemical structure. Other more specific factors that may be related to the chemical structure also determine the macroscopic behaviour of such materials, namely the relative position of the different segments of the polymeric chain, the molecular architecture (molecular weight distribution, branching, copolymer organisation, cross-linking extent, etc.), the crystalline environment and the pressure/temperature conditions. All these factors have a common impact in the material: they are strongly correlated to the mobility on the molecular level. That is why a huge amount of work has been devoted to the study of translational/rotational mobility that occurs within the polymeric chains. This review is intended to provide a brief survey on such kinds of mobilities, how they can be studied and what are their main characteristics. Examples on systems studied in our groups will be provided, obtained by dielectric and mechanical spectroscopies and differential scanning calorimetry. It will be mainly focused on molecular motions that occur in the solid phase (i.e., to temperatures up to the rubbery plateau). The dynamics in blends or copolymers will be avoided here, as they would deserve a special discussion in their own context. Special attention will be paid to the glass transition and the mobility that occurs below and above it. The dynamics that are observed in peculiar systems, such as semi-crystalline or liquid crystalline polymers, will be addressed.

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“…This evolution is characterized by changes in the free volume, enthalpy, and entropy of the polymer and will produce measurable changes in the mechanical properties (Struik [4], McKenna [5]). Physical aging is thermoreversible by heating the polymer above its T g and subsequently quenching the material.…”

Section: Classes Of Degradation Mechanismsmentioning

confidence: 99%

On the use of accelerated aging methods for screening high temperature polymeric composite materials

Thomas

1999

40th Structures, Structural Dynamics, and Materials Conference and Exhibit

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A rational approach to the problem of accelerated testing of high temperature polymeric composites is discussed. The methods provided are considered tools useful in the screening of new materials systems for long-term application to extreme environments that include elevated temperature, moisture, oxygen, and mechanical load. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for specific aging mechanisms.

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On the physics required for prediction of long term performance of polymers and their composites

Cited by 108 publications

References 39 publications

Strongly correlating liquids and their isomorphs

Strongly correlating liquids and their isomorphs

Molecular dynamics in polymeric systems

On the use of accelerated aging methods for screening high temperature polymeric composite materials

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