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Article Dans Une Revue Vibrational Spectroscopy Année : 2005

Micro-raman study of the compressive behaviour of advanced PA66 polyamide fibres in a diamond-anvil cell

Résumé

The micro/nanostructural evolution of ultra-high performance PA66 polyamide fibres has been studied by Raman spectroscopy in a diamond-anvil cell, up to 10 GPa. The nanostructures of these PA fibres consists of amorphous and crystalline (αI-type) regions (oriented + crystalline index not, vert, similar 60%). Information on the “crystalline” part of the fibre is obtained from three probes: (i) a low wave number collective mode at not, vert, similar100 cm−1 representative of the “friction/shear” of crystalline chains; (ii) Nsingle bondH stretching mode at not, vert, similar3300 cm−1, and (iii) Amide I (Cdouble bond; length as m-dashO) stretching mode at not, vert, similar1650 cm−1; the last two modes are representative of the inter-chain and intra-chain behaviour, respectively. A reversible transition between two regimes was evidenced at not, vert, similar3.7 GPa and assigned to the onset of the “contact” between neighbouring polyamide chains, i.e. the onset of possible fatigue. In the first regime (I), the “friction” wave number increased linearly (7.5 cm−1 GPa−1) whilst the distance between neighbouring (crystalline) chains decreased from not, vert, similar0.293 to not, vert, similar0.285 nm; in the second regime (II), the “friction” wave number still increased but at a much slower rate (<4.5 cm−1 GPa−1) and the Cdouble bond; length as m-dashO stretching mode of the amide group started to increase (not, vert, similar1.6 cm−1 GPa−1), indicating that the chains were squeezed together in all directions. The Nsingle bondH stretching mode continued to decrease, slowly (dNcdots, three dots, centeredO down to 0.289 or 0.2865 nm according to the data fitting procedure). Different behaviours are expected for amorphous and crystalline “regions”.

Dates et versions

hal-00154821 , version 1 (14-06-2007)

Identifiants

Citer

Philippe Colomban, G. Sagon, M. Lesage, José-Martin Herrera-Ramirez. Micro-raman study of the compressive behaviour of advanced PA66 polyamide fibres in a diamond-anvil cell. Vibrational Spectroscopy, 2005, 37, pp.83-90. ⟨10.1016/j.vibspec.2004.06.007⟩. ⟨hal-00154821⟩
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