370 JOURNAL OF COSMETIC SCIENCE \ J ...,Peptide, Hydrogen g' Bonds & Salt Links 00dl8 ° ° 0 .£._..peptide Bonds and van der Waals ---van der Waals S-CH2-C02- f=0 f=O =0 \ 1 Peptide, Hydrogen �Bonds & Salt Links oo�o 0 00 0 0 0 �eptide Bonds � and van der Waals � � � � f --¥an der Waals C=O f=O f=O _ "s-CH2-C02- � Figure 20. Reactions of the thioester linkage with TGA in the upper beta layer. \ J ...,Peptide, Hydrogen "7' Bonds & Salt Links oon s 0 OQ (1 Q .£._.peptide Bonds and van der Waats ---van der Waals S-CH2-C02- r=0 r=O =0 J Yeptide, Hydrogen -----::::::,.,,'Bonds & Salt Links oon s 0 OOry o�eptideBonds and van der Waals �an der Waals ._- ... ... .. ...----_rJ•.1•.• .. -. Figure 21. Reactions of thioester with TGA followed by quat & anionic in this same layer. cracks during heat drying, scale lifting by surfactants, and catastrophic failure. Failure in the wet state generally involves hydrophilic layers (endocuticle or the contact zone of the CMC) or bonding between hydrophilic layers, whereas failure in the dry state

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