HAIR COLORANTS 383 REFERENCES (1) J. F. Corbett, Hair colouring, Rev. Prog. Coloration, 4, 3-7 (1973). (2) J. F. Corbett, Hair dye toxicity, in Hair Research (Springer-Verlag, Berlin, 1981), pp. 529-535. (3) J. F. Corbett, The electronic spectra of nitrobenzenes containing two electron donor substituents, Spectrochim. Acta, 23A, 2315-2332 (1967). (4) K-Y Chu andJ. Griffiths, Colour and constitution of nitro- and dinitro-p-phenylenediamines and their N-methyl derivatives,J. Chem. Soc. Perkin I, 1194-1198 (1978). (5) J. Griffiths, Practical aspects of color prediction of organic dye molecules, Dyes and Pigments, 3, 211-233 (1982). (6) J. F. Corbett, The role of meta difunctional benzene derivatives in oxidative hair dyeing. I. Reaction with p-diamines,J. Soc. Cosmet. Chem., 24, 103-134 (1973). (7) K. C. Brown and J. F. Corbett, The role of meta difunctional benzene derivatives and oxidative hair dyeing. II. Reaction with p~aminophenols,J. Soc. Cosmet. Chem., 30, 191-211 (1979). (8) K. C. Brown andJ. F. Corbett, Benzoquinone imines. Part 16,J. Chem. Soc. Perkin II, 308-311 (1979). (9) J. F. Corbett, Benzoquinone imines. Part VIII,J. Chem. Soc. B, 1502-1509 (1970). (10) M. J. Shah, Thin-layer chromatography of redox reaction products of oxidative hair dyes, J. Soc. Cosmet. Chem., 28, 259-271 (1977). (11) A. deLabbey, A. Baudry, and P. Bore, Voltammetry in oxidative hair dyeing, 12th IFSCC Congress, Paris, France, 13-17 Sept. 1982. (12) J. F. Corbett, Benzoquinone imines. Part IX,J. Chem. Soc. Perkin II, 539-548 (1972). (13) P. Berth, E. Lieske, D. Rose, and D. Schrader, The possibilities and limits of new hair dye systems, 11th IFSCC Congress, Venice, Italy, 22-25 Sept. 1980. (14) L'Oreal, U.S. Patent 4259261. (15) Clairol, U.S. Patent 4119399. (16)• L'Oreal, U.S. Patent 4047888. (17) I. Schwartz, J. Kravitz, and A. D'Angelo, Laboratory evaluation of some oxidation hair color intermediates, Cosmet. Tolietries, 94, (4), 47-50 (1979). (18) K. C. Brown andJ. F. Corbett, Benzoquinone imines. Part 15,J. Chem. Soc. Perkin II, 304-307 (1979). (19) K. C. Brown andJ. F. Corbett, Benzoquinone imines. Part 17,J. Chem. Soc. Perkin II, 886-889 (1981). (20) L'Oreal, U.S. Patent 4125601. (21) M. Y. M. Wong, Kinetics of dye rinse from bleached hair,J. Soc. Cosmet. Chem., 23, 165-170 (1972). (22) H. H. Tucker and I. Schwartz, Purification of some intermediates for permanent hair colors, J. $oc. Cosmet. Chem., 22, 139-151 (1971). (23) For a recent review see J. A. Maclaren and B. Milligan, IVool Science (Science Press, Marrickville, Australia, 1981), pp. 165-180. (24) Clairol, U.S. Patent 3920384. (25) e.g., Gillette, U.S. Patent 4182612. (26) e.g. Shiseido, U.S. Patent 3993436. (27) H. Gottschalck and P. Stachowiak, Quantitative tracing of 2,4-diaminoanisole in hair coloring products, Aertzl. Kosmetol., 10, 265-266 (1980). (28) F. N. Marzulli, D. M. Anjo, and H. I. Maibach, In-vivo skin penetration studies of 2,4-toluenediamine, 2,4-diaminoanisole, 2-nitro-p-phenylenediamine, p-dioxane and N-nitrosodiethanolamine in cosmet- ics, Food Cosmet. Toxicol., 19, 734-747 (1981). (29) H. I. Maibach and L.J. Wolfram, Percutaneous penetration of hair dyes, J. Soc. Cosmet. Chem., 32, 223-229 (1981).

j. Soc. Cosmet. Chem., 33, 385-406 (December 1982) The physical properties of alpha-keratin fibers PROFESSOR M. FEUGHELMAN, CSIRO, Division of Textile Physics, 338 Blaxland Road, Ryde, New South IVales 2112, Australia. INTRODUCTION The bulk of the material forming all alpha keratins such as mammalian hair, wools, horns, claws, nails, and quills is a biological polymer consisting of polypeptide chains. These chains, themselves the products of the condensation of amino acids, have the general formula O R• H ..... C--N--CH--C--N--CH ...... H O R• where R•, R2, are the side chains of the amino acids of which twenty different compositions exist in keratin, their proportion varying with the type of keratin. The term alpha refers to the distinct high angle X-ray diffraction pattern (the a-pattern) which differentiates these keratins from others such as feather keratin (1), The distinguishing feature of all keratins, when compared with other proteins, is the presence of a large proportion of the sulphur containing amino acid cystine. This amino acid with two amino and two carbonyl groups can form part of two adjacent polypeptide chains, creating a covalent crosslink via the disulphide group of the cystine residue. These disulphide linkages are associated with some 10% of the amino acid residues of the keratins and confer a high degree of the physical and chemical stability to the keratin fibers. As will be noted further in this review, these disulphide links play a basic role in the process of setting both in the hairdressing and wool textile industries. At the molecular level ce-keratin fibers can not only be considered to consist of networks of polypeptide chains crosslinked by the covalent disulphide bonds, but (as with all proteins) a large variety of hydrogen bonds as well as Van der Waals interactions exist both between and within the chains. Of special interest in the physical properties of ce-keratin fibers are the Coulombic interactions, also referred to as "salt links," which exist between charged basic side chains of lysine, arginine, and histidine and the acidic side-chains of glutamic and aspattic acids. These basic and acidic side chain groups represent about a quarter of the residues of the ce-keratin structure. Hydrophobic bonds, interactions between chains created by the presence of water, have also been detected for ce-keratin fibers immersed in water (2). 385