Near Infrared (NIR) Fourier Transform (FT) Raman spectra of some nylons

Hansen, Susanne Brunsgaard; Christensen, D. H.; Nielsen, O. Faurskov

doi:10.1051/jcp/1993901797

Cited by 4 publications

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“…14 -17 Plots of the ratio of the relative intensity of the CH 2 bending mode ¾1440 cm 1 and the C O stretch (amide I, ¾1640 cm 1 mode versus the number of CH 2 groups per repeat unit (single-number nylons) excluding CH 2 adjacent to C O bonds have been investigated. 18 The relative intensities of the different components of the C-H stretching band (2900-3000 cm 1 range) can be correlated with the repeat unit arrangement. 19 The low-wavenumber region shows components assigned to a hydrogen bond mode, which varies with the nylon  structure.…”

Section: Structure Of Polyamide 66mentioning

confidence: 99%

“…19 The low-wavenumber region shows components assigned to a hydrogen bond mode, which varies with the nylon  structure. 18 At least three PA66 polymorphs,˛,ˇand , have been characterized that generally co-exist in various amounts, depending on the processing conditions. The most stable structure is the˛-phase, which is comprised of planar sheets of hydrogen-bonded molecules stacked upon one another.…”

Section: Structure Of Polyamide 66mentioning

confidence: 99%

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(Nano)structure, skin/core and tension behaviour of polyamide fibres

Marcellan

Colomban

Bunsell

2004

J Raman Spectroscopy

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International audienceThe micro/nanostructural evolution of ultrahigh-performance and textile (containing a dispersion of TiO2 powder) polyamide 66 fibres during tensile loading and failure initiation was studied using Raman spectroscopy low-wavenumber collective modes (100 cm-1) as a mechanical probe representative of the crystalline domains. The analysis of the wavenumber distribution revealed the skin/core heterogeneity. A compressive residual stress in the skin was evaluated at about 200 MPa from calibration plots. The homogeneity of the TiO2 grain dispersion was mapped on fibre sections and scanned along their lengths. In situ analysis at different strain levels shows that the amorphous region accommodates the stress up to ca 350 MPa, from which point elastic behaviour is observed. Particular attention was devoted to analysing crack formatio

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Section: Structure Of Polyamide 66mentioning

confidence: 99%

Section: Structure Of Polyamide 66mentioning

confidence: 99%

(Nano)structure, skin/core and tension behaviour of polyamide fibres

Marcellan

Colomban

Bunsell

2004

J Raman Spectroscopy

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show abstract

“…14 -17 Plots of the ratio of the relative intensity of the CH 2 bending mode (¾1440 cm 1 ) and the C O stretch (amide I, ¾1640 cm 1 ) mode versus the number of CH 2 groups per repeat unit (single number nylons) excluding CH 2 adjacent to C O bond have been investigated. 18 The relative intensities of the different components of the C-H stretching band (2900-3000 cm 1 range) can be correlated to the repeat unit arrangement. 19 The low wavenumber region shows a narrow component assigned to collective T 0 mode vibration of the chain, also involving the hydrogen inter-chain bond mode.…”

Section: Structure Of Pa 66mentioning

confidence: 99%

Micro‐Raman study of the fatigue fracture and tensile behaviour of polyamide (PA 66) fibres

Ramirez

Colomban

Bunsell

2004

J Raman Spectroscopy

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The micro/nano structural evolution of two different types of ultra-high-performance polyamide (PA) 66 fibres, before and after tensile fatigue loading and failure, was studied using Raman spectroscopy. The nanostructure of these PA fibres consists of amorphous and crystalline domains. Two probes were considered: (i) low-wavenumber collective modes at ∼100 and ∼70 cm −1 as representative of the crystalline and amorphous domains, respectively; and (ii) N-H stretching mode at ∼3300 cm −1 , as representative of the inter-chain behaviour. The analysis of the wavenumber distribution revealed that the skin/core heterogeneity is a maximum for the amorphous domains. The residual stress in the skin was evaluated at about 200 and 400 MPa from calibrations plots for crystalline and amorphous domains, for the two types of fibres. This stress disappears after thermal treatment around T g . In situ analysis at different strain levels shows that the amorphous regions accommodate the stress up to ∼350 MPa, from which point elastic behaviour is observed. The analysis of a series of fibres failed in fatigue showed that amorphous domains are highly stressed during the failure and remnant compression can be measured. The extent of the stressed region extends to typically 100-400 µm from the fracture. Examination of the N-H wavenumber shift shows that the fracture squeezes the polymer chains together. Fatigue failure is explained by the loss of compliance in the amorphous region.

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Low-frequency Raman spectroscopy

Colaianni

Nielsen

1995

Journal of Molecular Structure

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Near Infrared (NIR) Fourier Transform (FT) Raman spectra of some nylons

Cited by 4 publications

References 0 publications

(Nano)structure, skin/core and tension behaviour of polyamide fibres

(Nano)structure, skin/core and tension behaviour of polyamide fibres

Micro‐Raman study of the fatigue fracture and tensile behaviour of polyamide (PA 66) fibres

Low-frequency Raman spectroscopy

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