Wool fiber analysis

Parachlorobenzotrifluoride, 6 1341 Paracortex, in wool fibers, 22 173 Para-crystalline lattice model, 24 464 Paracyclophane synthesis, 24 38 PARAFAC (PARAllel FACtor analysis),... 

Analysis of Plasma Deposited Flurocarbon Coatings on Polymer Films and Wool Fibers... 

Hair. Until recently, the application of luminescence specifically to the analysis of human hair has not been attempted in any systematic manner. It has been shown that three of the amino acids, i.e., phenylalanine, tyrosine, and tryptophan, found in hair protein both fluoresce and phosphoresce (15). It has been established that for other proteins that contain all three of the amino acids, the luminescence (both fluorescence and phosphorescence) is predominately the result of the tryptophan chromophores, with possibly some contribution from the tyrosine (15)- More directly related to the luminescence of hair are the-studies of Konev (23) involving the luminescence of wool keratin. He observed both fluorescence and phosphorescence from wool fibers that were characteristic of tryptophan. 

This conformational analysis using conformation-dependent C CP/MAS NMR chemical shifts was applied to estimate conformational transitions of SCMKA by stretching, heating, or steam-treating [87-90]. It is confirmed that the )S-sheet form appears and the a-helix content decreases upon stretching and steam-treating, as observed for native wool fiber. For SCMKA heated at 200°C for 3 h in vacuo, the C CP/MAS NMR spectrum shows the peaks are broader than those of other treated samples. This indicates the existence... 

Under conditions of lower pH, where this reduction process is reaction-controlled rather than diffusion-controlled, equation B or C can be rate-limiting. If equation B is rate-limiting, the reaction is simply second-order—first-order with respect to mercaptan and hrst-order with respect to keratin disulhde—and analysis is not as complicated as when Equation C is rate-limiting. In kinetic studies for a complex material like human hair or wool fiber, an excess of thiol is most commonly employed, and one generally assumes the reaction in Equation B to be ratecontrolling. The reaction is then described by pseudo-hrst-order kinetics (first-order with respect to keratin disulhde). 

Analysis of DNA by polymerase chain reaction has also been shown to be a useful, but expensive, means of distinguishing between different hair and wool fibers. 

In a pilot study, it was discovered that an ultraviolet zone (UVO) based method, which has been developed for surface treating wool fibers, could be used to oxidatively modify polymer surfaces. Electron spectroscopy for chemical analysis (ESCA) and contact angle results indicated that the treatment was effective on PE and a polyetheretherketone (PEEK). It produced changes in surface oxygen chemistry and free energy, which increased polarity and improved wettability of the surface. Composite lap shear tests showed that the treatment gave a marked improvement in adhesion and that an optimum joint strength is achieved at low treatment times (<1 min). 

Analysis of the data obtained testifies that in all types of wool fibers (but to different extent) reduction of quantity of amino acids with disulfide bonds (cystine, methionine) and ones related to polar (hydrophilic) amino acids, including serine, glycine, threonine, and tyrosine, is observed. These very amino acids provide hydrogen bonds imparting stability to keratine stracture. 

Amino Acid Analysis. Protein fibers, such as wool and alpaca, consist of macromolecules that are naturally formed during the growth of the hair. These large molecules are actually copolymers of about 20... 

Quantitative analysis of fiber mixtures in polyester-wool textures by KBr pelleting has been described by Hannah et al. (1975). Deviations from the real values were approximately 1%. 

Wortmann F J, Quantitative fiber mixture analysis by scanning electron microscopy. Part III Round trial results on mohair/wool blends , Textile Research Journal, 1991,61, 371-374. 

This method involves oxidation of hair using peracetic acid. Analysis of the gamma-keratose from human hair indicates a higher proportion of sulfur compared to the other keratose fractions or to whole fiber [42]. Cor-held et al. [93] have isolated matrix material from merino wool by this procedure. Chemical analysis shows a relatively high proportion of sulfur and a correspondingly greater proportion of cystine compared to the other fractions or to whole fiber [42]. 

The data for cuticle analysis are based on the work of Bradbury et al. [16] who analyzed cuticle and whole fiber from several keratin sources, including human hair, merino wool, mohair, and alpaca. These scientists concluded that there is very nearly the same difference between the amino acid composition of the cuticle and each of these fibers from which it was derived. They listed the average percentage differences used in these calculations. More recent analyses of cuticle and whole fiber of human hair [68, 69] are in general agreement with these data [18]. 

The ingredients for pretreatments can range from simple to complex, with particular formulations for particular dye types or fabrics, or combinations of these. This chapter is an overview of pretreatment as a process, rather than a specific chemical or physical analysis of a particular step in that process. References are included for those interested to further their own research. Specific ingredients tend to be confidential as commercially sensitive, but some recipes are publicly available for use as a starting point for experimentation (Bae, 2007, p. 46 Hawkyard, 2006 Provost et al., 2003). Many of the pretreatment formulations have been aimed at fashion fabrics, so they are biased toward fiber types such as cotton, silk, nylon, and wool. The principle and most common ingredients for pretreatments are thickeners, alkalis, and urea ... 

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