L'Interface Dans Les Composites Pps‐Carbone

Böudet, Alain M.; Teyssèdre, G.; Caramaro, L.; Chabert, B.

doi:10.1002/bscb.19890980917

Cited by 3 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, charges themselves may act as 'defects' inducing crystal growth preferentially from the surface of such defects. Figure 21.22 shows an example of heterogeneous germination of Poly(phenylene sulphide) -PPS-on a Carbon fiber: very specific morphology, called transcrystalline region, is obtained in this case [41]. It results from a dense crystal nucleation on the fiber and a growth of crystalline lamella along radial directions of the fiber.…”

Section: Structural Reorganizationmentioning

confidence: 99%

Ageing and Degradation of Multiphase Polymer Systems

Colin¹,

Teyssèdre²,

Fois³

2011

Handbook of Multiphase Polymer Systems

View full text Add to dashboard Cite

Ageing can be defined as a slow and irreversible variation as a function of time (in use conditions) of a material structure, morphology or composition leading to a detrimental change in its use properties. The cause of this change can be the own material instability or its interaction with the environment of exposure. The definition so given is that viewed from an application point of view. There are issues associated with this definition that deserve to be mentioned. First, there are ageing mechanisms, essentially of a physical nature as detailed below, that are not irreversible in nature (e.g. crystallinity change, structural recovery, water uptake without loss of the integrity of the chemical structure, etc.), but may lead to a change in the use properties of these materials. The reversibility is in principle achievable by, e.g. thermal treatment or drying. However, this is not necessarily compatible with the use of materials as pieces, or the material will evolve again anyway when exposed to use environmental stresses. Second, irreversible material evolution in itself does not necessarily imply a detrimental change of use properties. It can even result in an improvement of properties. This represents indeed a marked difficulty when attempting to define so-called 'ageing markers' for materials, i.e. material properties to be monitored for health monitoring purpose: the marker must be 21.1.2 Classification of Ageing Types There is a wide variety of polymer ageing types. Each one is a complex phenomenon, but decomposable into a set of elementary mechanisms that can be interactive: chemical reactions, macromolecular motions, molecular species transport into the polymer, crystallinity change, etc. Unfortunately, there is no entirely satisfactory method for their classification, because the most rigorous criteria, in theory, are often open to criticism in practice. The simplest and most agreed method consists in distinguishing two main ageing families according to the nature of involved mechanisms: r chemical ageing is responsible for a variation of the macromolecule chemical structure r physical ageing affects the macromolecule conformation, the material morphology or composition, without altering the macromolecule chemical structure. Then, the different ageing types, defined in terms of the main ageing driving environmental stress, involve one of the two families of mechanisms defined above: r Thermal ageing is initiated by material's own instability. Its kinetics essentially depends on temperature and atmosphere composition. It can be a chemical or a physical ageing, or a combination of them. r Humid ageing is due to a chemical or a physical interaction of polymer with water, the latter being either in a liquid or a vapor state. r Photo-chemical ageing results from polymer interaction with light rays (in general, UV solar radiations). Atmospheric oxygen plays, in general, an important role (photo-oxidation). r Radio-chemical ageing is due to the polymer interaction with ionizing (γ, β, α, neutrons, etc.) rays. ...

show abstract

Section: Structural Reorganizationmentioning

confidence: 99%