Infrared study of the effect of heat on wool

Moharram, M. A.; Abdel-Rehim, T. Z.; Rabie, S. M.

doi:10.1002/app.1981.070260315

Cited by 8 publications

(6 citation statements)

References 16 publications

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“…It is known that the properties of wool fibers change after they are exposed to thermal effect. Many studies were devoted to understand the thermal characteristics of the wool fibers on the basis of structural changes and the effect of temperature on the spectroscopic properties, the stress–strain curves, and the tensile properties of wool fibers . However, the tensile characteristics of the wool fibers after the wool fibers were exposed to heat treatment at different elevated temperatures were not investigated much in detail.…”

Section: Introductionmentioning

confidence: 99%

Uniaxial tensile properties of TiO₂ coated single wool fibers by sol‐gel method: The effect of heat treatment

Aksakal

Koç

Bozdoğan

et al. 2013

J of Applied Polymer Sci

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Single wool fibers were coated with TiO 2 by using the sol-gel method. The uniaxial tensile properties of TiO 2 coated single wool fibers heated at different temperatures from 25 to 200 C were investigated and compared with those of uncoated single wool fibers. It was observed that the shape of the stress-strain curve of TiO 2 coated wool fibers became the same as uncoated wool fibers and showed a similar tendency of change to uncoated wool fibers with increasing temperature. But, the TiO 2 coated wool fibers obtained higher rigidity than uncoated wool fibers and up to their rupture points; they obtained higher stress levels in three deformation regions in the stress-strain curves, which indicates stronger wool fibers. Although the breaking extension of TiO 2 coated wool fibers decreased little by about 8%, the Young's modulus of TiO 2 coated wool fibers increased significantly by 19%, which was caused mostly by an increment in the stiffness of the cuticle layer of the wool fiber, and remained relatively higher than that of uncoated wool fibers after heat treatments. Structural changes in both uncoated and TiO 2 coated single wool fibers due to thermal effect, which caused the changes in the uniaxial tensile properties and the thermal behaviors of these fibers were discussed by using spectroscopic and thermal analysis methods in detail.

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Section: Introductionmentioning

confidence: 99%

Uniaxial tensile properties of TiO₂ coated single wool fibers by sol‐gel method: The effect of heat treatment

Aksakal

Koç

Bozdoğan

et al. 2013

J of Applied Polymer Sci

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“…The use of FTIR and XRD (X-ray diffraction) methods in the study of structure or properties of cotton cellulose has been a subject of interest for a number of researchers. [8][9][10][11][12][13] However, till the present time the effect of microwave heating on the structural properties of cotton fibers and on the mercerization mechanism has not yet been fully investigated. The main purpose of the present study is to apply FTIR spectroscopy to investigate the microwave heating induced changes in the structural properties of cotton fibers and also the effect of microwave irradiation on the mercerization mechanism of cotton fibers.…”

Section: Introductionmentioning

confidence: 99%

FTIR spectroscopic study of the effect of microwave heating on the transformation of cellulose I into cellulose II during mercerization

Moharram

Mahmoud

2007

J of Applied Polymer Sci

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Fourier transform infrared (FTIR) spectroscopy techniques were used in the study of the effect of microwave (MW) heating on the structural properties of cotton fibers and on the mercerization mechanism of these fibers. Samples of the fibers were microwave heated for different times and different microwave powers. Also, mixtures of cotton fibers and aqueous solution of NaOH with different concentrations were exposed to microwave radiation for different times and different powers. It was found that microwave heating of cotton fibers under these experimental conditions causes no observable changes in their spectral features apart from slight changes in the intensities of the absorption bands. The determined values of the absorbances ratio A1375 cm 21 /A2900 cm 21 revealed that microwave heating for short periods and at low powers decreases the crystallinity of cotton as the result of the drying effect of microwave heating, while microwave heating for longer periods and at higher power results in recristallyzation of the fibers. The analysis of the experimentally obtained data revealed that microwave heating that causes molecular motions by migration of ions and rotations of the dipoles produces no considerable effects on the mechanism of mercerization but only reduces the concentration of NaOH in the solution and the time of treatment which are needed for the complete transformation of cellulose lattice type I into cellulose lattice type II without any heating. Also it was found that the magnitude of reductions depends on the applied power. Moreover the results proved that the deconvolution and the second derivatives of the FTIR spectra of cotton fibers can be used as a useful tool for distinguishing cellulose lattice type II from cellulose lattice type I.

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“…The band frequencies of wool fibre (Figure 3.3) are generally in good agreement with the assignments from previous work. 7,49,84,85 This is illustrated in Table 3.1.…”

Section: Infrared Spectroscopy (Ftir)mentioning

confidence: 99%

“…86 Also 1046 cm -1 may be assigned to vibrations of cysteic acid groups. 84,85 A very weak band at 499 cm -1 is assigned to the symmetric stretch of -S-S-vibrations. 87…”

Section: Vw -Very Weakmentioning

confidence: 99%

“…At very high temperatures (~ 90 o C), the -S-S-bonds in the cystine residues break more readily and oxidize into cysteic acid residues. 27,84 These cysteic acid (-RSO 3 H) groups may bind with metal ions (M 2+ (aq) ). When heated above 85 o C, usually for more than 8 hours, the high metal uptake may be attributed to the formation of metal sulfide and to the ligation of cysteic acid groups to metal ions.…”

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Some Uptake Studies of Metal Ions and the Formation of Cu₂0 Particles in Wool

Samarasinghe¹

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<p>This research programme is concerned with the uptake studies of Cu2+, Zn2+ and Mn2+ at different conditions, by merino wool fibres and also uptake studies of Cu2+ ions by chemically modified wool fibres. Cu2O particles and Cu complexes are formed within merino wool by an in situ reaction with sodium borohydride and thioglycoloic acid respectively. The d-block elements have the ability to bind chemically to certain functional groups present within the keratin protein of wool. The absorption of the Cu2+, Mn2+ and Zn2+ from solution by wool fibres under different conditions notably, time, temperature and initial concentration have been studied. The optimum temperature and reaction time to give highest absorption of the Cu2+ by the wool fibre was found to be 90 oC and one hour without modifying the nature of the wool, from a solution of Cu2+ concentration of 450 mg L-1. Cu2+ was found to give the greatest absorption by the wool fibres, whereas Zn2+ and Mn2+ were found to be absorbed the least. The absorption of Cu2+ ions increases with increasing temperature. At the higher temperature of 90 oC, the -S-S- bonds in the cystine amino acids break more readily, generating thiol and cysteic acid groups to bind with copper ions. The uptake of Cu2+ by ethylenediaminetetraacetic dianhydride (14 mg g-1 of wool) or thioglycolic acid (42.5 mg g-1 of wool) or sodium borohydride (41.8 mg g-1 of wool) treated merino wool fibres increases with respect to unmodified wool (8 mg g-1 of wool). NaBH4 treated merino wool reduces Cu2+ ions to Cu2O particles which form within the wool fibres by an in situ reaction. TGA treated merino wool provides additional functional groups to bind with copper ions and Cu2O particles also likely to be formed within TGA treated wool composites. The metal ions were absorbed into the fibres under various conditions and the extent of absorption was quantified. The form and binding of the Cu2O particles or Cu2+ ions onto the wool fibres are studied using UV-Visible, FTIR, XRD, SEM, EDS and TEM methods.</p>

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Infrared study of the effect of heat on wool

Cited by 8 publications

References 16 publications

Uniaxial tensile properties of TiO₂ coated single wool fibers by sol‐gel method: The effect of heat treatment

Uniaxial tensile properties of TiO₂ coated single wool fibers by sol‐gel method: The effect of heat treatment

FTIR spectroscopic study of the effect of microwave heating on the transformation of cellulose I into cellulose II during mercerization

Some Uptake Studies of Metal Ions and the Formation of Cu₂0 Particles in Wool

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Infrared study of the effect of heat on wool

Cited by 8 publications

References 16 publications

Uniaxial tensile properties of TiO2 coated single wool fibers by sol‐gel method: The effect of heat treatment

Uniaxial tensile properties of TiO2 coated single wool fibers by sol‐gel method: The effect of heat treatment

FTIR spectroscopic study of the effect of microwave heating on the transformation of cellulose I into cellulose II during mercerization

Some Uptake Studies of Metal Ions and the Formation of Cu₂0 Particles in Wool

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Uniaxial tensile properties of TiO₂ coated single wool fibers by sol‐gel method: The effect of heat treatment

Uniaxial tensile properties of TiO₂ coated single wool fibers by sol‐gel method: The effect of heat treatment