Although chrome is considered as the major tanning agent in the production of all types of hides and leather worldwide, it represents a serious source of environmental pollution. Therefore, polyamidoamine hyperbranched polymer (HPAM) was involved in pretanning of the depickled hides to enhance the chromium uptake during the tanning process. The key parameters which affect the exhaustion and fixation of chrome tan including shrinkage temperature of the tanned leather were studied. The results showed a significant improvement in the chrome exhaustion, the shrinkage temperature, and the texture and softness of the leather treated by HPAM. 1. Introduction At the last decades, hyperbranched polymers have attracted great attention due to their dendritic architecture as highly branched polymers and their unique properties including lower viscosity, higher solubility, and higher amount of reactive terminal groups, compared with their equivalent linear analogues. Furthermore hyperbranched polymers are synthesized via one pot reaction using various techniques such as step-growth polycondensation, self-condensing vinyl polymerization, ring-opening polymerization, self-condensing ring-opening polymerization, and proton transfer polymerization [1–5]. Several types of hyperbranched polymers were prepared such as polyphenylenes, polyethers, polyesters, polyamides, polycarbonates, poly(ether ketones), and polyurethanes [6–12]. Generally, hyperbranched polymers are readily feasible for different potential applications, such as toughening and cocuring agents, multifunctional initiators, rheology control compounds for surface modification, medical applications, nanofillers for polymer nanocomposites, nonlinear optics, nanoporous generators for low dielectric constant insulators, coatings, and drug delivery systems [13–24]. Therefore, hyperbranched polymers are of immense importance for industrial applications. Accordingly, this work was devoted to explore their application for further use in the leather industry as pretanning agents (modifying agent) to enhance the uptake of chrome during tanning process. In tanning process, protein of raw hides, which is easily attacked by organisms, is converted to a stable fiber structure, preventing their putrefaction. Although several types of metallic salts are employed for tanning of leather, chromium salts are still considered as the most important tanning agents used for all types of hides and leather. Generally, chromium salts are involved in more than 80% of the tanning industry worldwide [25]. However, under normal tanning
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