Layered Double Hydroxide/Polymer Supramolecule with Different Structures for Leather Multiperformance Intensification

LDH/P supramolecule with exfoliated and intercalated structure by exfoliation/adsorption and in situ polymerization method is prepared, respectively. Afterward, the LDH/polymer supramolecule with exfoliated (LDH/P-E, exfoliation/adsorption) and intercalated (LDH/P-I, in situ polymerization) and partial exfoliated and partial intercalated (LDH/P-B, physical blending, reported in the previous work) is used in leather tanning and retanning process to evaluate the structure-activity relationship between LDH/P and leather application performance. LDH/P supramolecule with exfoliated structure shows the best intensification ability to most of the leather performances, and the sequence of intensification ability of LDH/P is LDH/P-E > LDH/P-B > LDH/P-I. This is related to the size and penetration property of LDH/P. For the leather performance intensification, the positively charged LDH layers can promote the absorption of negatively charged leather chemicals, and thus the dyeing and softness of leather can be intensified. The nanolayered structure of LDH filled between leather gaps can play a toughening and block effect, and thus the physical and mechanical strength, thickening rate, and the inhibition of volatilization of small organic molecule property of leather can be intensified. Furthermore, the reduction of chemical oxygen demand value of dyeing waste water is also an evidence that the LDH/P is an environmental retanning auxiliary.