Eco-friendly nanosilica-filled lubricant for fatliquoring leather

The present work focused on the synthesis and characterization of two different nanosilica (named NS-1 and NS-2) particles for use with lubricant in fatliquoring leather. NS-1 was prepared in a base-catalyzed reaction at room temperature via a sol-gel-based eco-friendly approach, while NS-2 was synthesized using the bi-functional silane coupling agents in an acid-catalyzed medium at 60 °C. After the NS particles in different contents are added separately to the lubricant (coded NSL-1 and NSL-2), they were applied to leather as a nanosilica-filled lubricant for fatliquoring leather. NS-1 particles with an amorphous and spherical-shaped structure had better thermal stability (at 700–900 °C), a smaller particle size of 150 nm, and particle size distribution, and good wettability properties due to its lower contact angle of 29° than NS-2 particles. NSL-1 containing 10% uniform nanosilica particles was determined to provide well isolation and inter-fibrillar opening in fibrous structures by the SEM analysis. Compared to the others, NS-1- filled lubricant gave a good lubrication effect and exhibited enhancing better and strong the fibrous network structure of the leather consisting of very thin and tight collagen fibers. Also, the leathers treated with NS-1- filled lubricant showed that they can be exhibited better tensile strength, percentage extension, good touching, and fat uptake. The prepared NS particle via a greener sol-gel approach proved a filling effect on the leather and can be used for application in the leather industry as a lubrication agent due to their good properties.