Novel Wet-White Tanning Approach Based on Laponite Clay Nanoparticles for Reduced Formaldehyde Release and Improved Physical Performances

Abstract

In this work, a novel eco-friendly wet-white tanning approach based on tetrakis­(hydroxymethyl) phosphonium sulfate (THPS) and synthetic Laponite clay nanoparticles has been developed to reduce potential HCHO risk as well as to improve leather performances. Our results indicate that the hydrothermal stability enhancement of the leather and the HCHO release are closely related to the dosage of THPS and final float pH in the THPS-based wet-white tanning process. The introduction of Laponite can cause distinct increase in shrinkage temperature (T s) of the combination tanned leather and reduced HCHO contents, implying the presence of synergistic effects between THPS and Laponite. The wet-white tanning system of 2.5% THPS combined 3% Laponite by two-bath method at final pH ∼4.5 is thus optimized, conferring the leather with a T s above 85 °C. Laponite clay nanoplatelets can be evenly bound between collagen fibrils without altering the native D-periodic banding patterns. Moreover, the novel combination tanning not only improves yellowing resistance and lightfastness but also enhances strength properties of the wet-white leather. These findings provide a potential application of Laponite to meet growing demands for reasonable tanning materials and related technologies toward eco-friendly leather manufacture.

Hierarchical Incorporation of Surface-Functionalized Laponite Clay Nanoplatelets with Type I Collagen Matrix

“…After incubation for 24 h, the as-prepared CF nanocomposites (defined as LAP–CFs, LAP–APTES–CFs, and LAP–THPS–CFs) were intensively rinsed with deionized water to remove the unbound NPs. Additionally, CFs treated with THPS (defined as THPS–CFs) were prepared using the reported methods in reference . All the resulting CF matrices mentioned above were processed into slices with a thickness of 30 μm using a Leica CM1950 cryostat microtome after being lyophilized at −43 °C for 24 h for further structural characterizations.…”

“…Additionally, CFs treated with THPS (defined as THPS−CFs) were prepared using the reported methods in reference. 37 All the resulting CF matrices mentioned above were processed into slices with a thickness of 30 μm using a Leica CM1950 cryostat microtome after being lyophilized at −43 °C for 24 h for further structural characterizations.…”

Sustainable and safer nanoclay composites for multifaceted applications

“…Shi et al 265 introduced a novel eco-friendly wet-white tanning approach by synthesizing a hybrid of tetrakis(hydroxymethyl) phosphonium sulfate (THPS) and synthetic LAPONITE® clay nanoparticles. These stable hybrid materials may be used to reduce the potential formaldehyde (HCHO) risk and improve the performance of leather with enhanced strength properties.…”

Biomass-derived aldehyde tanning agents with in situ dyeing properties: a ‘Two Birds with One Stone’ strategy for engineering chrome-free and dye-free colored leather

“…These are attributed to their ability to bind with the –NH 2 group on the collagen fibers (CFs) via constructing a robust covalent crosslinking structure. However, the continuous formaldehyde (FA) release from these tanned leathers during commercial use is difficult to avoid, 10,11 resulting in excessive FA in the leather products. Besides, the aldehyde organic tanning agents mentioned above result in tanned leather with a low isoelectric point, causing poor absorption and fixation of the commonly used wet-finishing materials.…”