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90°. 90°. 0°. 3500 . 3500 . 3000 . 3000 . 2500 . 2500 . 2000 . 2000 . 1500 . 1500 . 1000 . 1000 . Wavenumber / cm -1. Silk. Crystallinity Index X = I 1615 / I 1655. polarised infrared spectra. Orientation parameter = X 90° / X 0°. ageing. Heat Aged
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90° 90° 0° 3500 3500 3000 3000 2500 2500 2000 2000 1500 1500 1000 1000 Wavenumber / cm-1 Silk Crystallinity Index X = I1615 / I1655 polarised infrared spectra Orientation parameter = X90° / X0°
Heat Aged Light Aged Untreated Silk Heat Aged Light Aged ‘Pink’ Tin Heat Aged Light Aged Orientational Order Parameter, W Dynamite - - Ammoniacal Tin Heat Aged - - Iron Heat Aged Heat Aged Light Aged ‘Blue’ Iron Breaking Load /g pol infrared signatures of silk ageing
Raman spectrum of silk Raman spectrum of silk confocal microspectroscopy
Ascertaining the condition of historic textiles: monitoring deterioration using infrared and Raman spectroscopy • microstructure determines mechanical behaviour • IR/Raman spectroscopy probes fibre crystallinity • microstructure determines mechanical behaviour • IR/Raman spectroscopy probes fibre crystallinity • other condition markers: moisture sorption • NIR a valuable non-destructive probe
Moisture sorption at 90% RH modern linen 17.7 aged linen 13.1 Adsorption-desorption isotherm for linen 20 18 16 14 Adsorption new 1 cm 12 Desorption new 10 Change in mass /% Adsorption aged 8 Desorption aged 6 4 2 0 0 20 40 60 80 100 RH /%
Wavenumber / cm-1 3500 3500 3000 3000 2500 2500 2000 2000 1500 1500 1000 1000 OH OH mid- infrared spectrum of linen
Near infrared (NIR) spectroscopy a non-invasive probe
NIR spectrum of Victory sailcloth Wavenumber (cm-1) 7500 7000 6500 6000 5500 5000 4500 4000
cotton wool silk Wavenumber (cm-1) 7500 7000 6500 6000 5500 5000 4500 4000 NIR spectra of natural fibres
Wavenumber (cm-1) a c 7500 7500 7000 7000 6500 6500 6000 6000 5500 5500 5000 5000 4500 4500 4000 4000 NIR spectrum of linen sailcloth
2 CH Wavenumber (cm-1) 6000 5800 5600 5400 5200 5000 4800 4600 second derivative NIR spectrum
20% 50% 80% 2 OH + OH Wavenumber (cm-1) 7500 7000 6500 6000 5500 5000 4500 4000 surrogate aged linen sailcloth RH
Wavenumber (cm-1) 7500 7000 6500 6000 5500 5000 4500 4000 excess bound aged linen 50% RH difference spectrum (80% - 20%)
modern linen aged linen Wavenumber (cm-1) 6000 5500 5000 4500 4000
NIR-derived moisture sorption data 20 modern linen 18 16 aged linen 14 12 10 8 Change in mass /% 6 4 gravimetric isotherms 2 0 0 20 40 60 80 100 RH /%
Conclusions Informed preservation demands condition monitoring Mechanical behaviour is effected by microstructure Vibrational spectroscopy can probe crystallinity Moisture sorption is another signature of ageing NIR spectroscopy offers non-destructive interrogation Informed preservation demands condition monitoring Informed preservation demands condition monitoring Mechanical behaviour is effected by microstructure Informed preservation demands condition monitoring Mechanical behaviour is effected by microstructure Vibrational spectroscopy can probe crystallinity Informed preservation demands condition monitoring Mechanical behaviour is effected by microstructure Vibrational spectroscopy can probe crystallinity Moisture sorption is another signature of ageing Paul Garside, Averil Macdonald and colleagues at the Textile Conservation Centre Robert Alexander, Perkin Elmer Arts and Humanities Research Council Acknowledgements Back to Index.ppt