Fracture micromechanics of polymer materials

Tamusz, Vitauts P.; Kuksenko, V. S.

doi:10.1007/978-94-017-1597-3

Cited by 49 publications

(25 citation statements)

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“…As a result, stress and strain are highly localized along these regions. Microcracks or crazes can be easily initiated and the crack can propagate through these weak defects [37].…”

Section: Discussionmentioning

confidence: 99%

Crystalline organization and toughening: example of polyamide-12

Corté

Beaume

Leibler

2005

Polymer

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“…As a result, stress and strain are highly localized along these regions. Microcracks or crazes can be easily initiated and the crack can propagate through these weak defects [37].…”

Section: Discussionmentioning

confidence: 99%

Crystalline organization and toughening: example of polyamide-12

Corté

Beaume

Leibler

2005

Polymer

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“…Whatever the exact mechanisms may be, it appears that degradation evolution equations based on chemical reaction rate theory describe the kinetics of cellulose degradation reasonably well, although certain modifications may be necessary to account for experimental observations. On the other hand, there is now a great deal of experimental evidence in polymers that chain scission occurs during the degradation and failure of polymers and particularly, although the concentration of chain scissions is a time function of the degradation, the total accumulation of chain scissions at failure for a given polymer is, to a good approximation, independent of the loading conditions (Kukensko and Tamuzs 1981). The chain scission concentration N of a polymer thereby represents a logical scalar parameter with which to characterize degradation within the material.…”

Section: Degradation Evolution Equation Of Cellulose At a Molecular Lmentioning

confidence: 98%

On the degradation evolution equations of cellulose

Ding

Wang

2007

Cellulose

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Cellulose degradation is usually characterized in terms of either the chain scission number or the scission fraction of cellulose unit as a function of degree of polymerisation (DP) and cellulose degradation evolution equation is most commonly described by the well known Ekenstam equations. In this paper we show that cellulose degradation can be best characterized either in terms of the percentage DP loss or in terms of the percentage tensile strength (TS) loss. We present a new cellulose degradation evolution equation expressed in terms of the percentage DP loss and apply it for having a quantitative comparison with six sets of experimental data. We develop a new kinetic equation for the percentage TS loss of cellulose and test it with four sets of experimental data. It turns out that the proposed cellulose degradation evolution equations are able to explain the real experimental data of different cellulose materials carried out under a variety of experimental conditions, particularly the prolonged autocatalytic degradation in sealed vessels. We also develop a new method for predicting the degree of degradation of cellulose at ambient conditions by combining the master equation representing the kinetics of either percentage DP loss or percentage TS loss at the lowest experimental temperature with Arrhenius shift factor function.

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“…In this case the fracture process has to result from a drastic localization at certain sites. The dangerous sites can be located in thin surface layers of the polymer where the submicrocrack concentration can be several times higher than that in the volume [116]. Our studies have indicated, however, that the most probable sites for submicrocrack formation and coalescence in a highly oriented polymer are the kink borders [117], where microfibrils are ruptured due to a sharp bending ( Figure 18).…”

Section: Drawing Arrest and Fracture Of Oriented Polymersmentioning

confidence: 86%