广东费飘职业故本学院 Guangdong Inatitute of Textile Technology Structures of wool fibers Intermolecular bonding cross-linking: 2 cystine amino acids one on each of the two adjacent chains form a cystine link, a covalent bond(s-s bond, increasing strength and elasticity. Ionic bond: salt linkage formed when two amino acids are in close proximity responsible for reacting with acid dyes Hydrogen bonds: between amide groups but have relatively low density due to more amorphous phase and packing difficultiesStructures of wool fibers Intermolecular bonding ◼ Cross-linking: 2 cystine amino acids one on each of the two adjacent chains form a cystine link, a covalent bond (S-S bond), increasing strength and elasticity. ◼ Ionic bond: salt linkage formed when two amino acids are in close proximity: responsible for reacting with acid dyes. ◼ Hydrogen bonds: between amide groups but have relatively low density due to more amorphous phase and packing difficulties