Pages 182–184
Abstract
Research summary supplied by the authors
The increasing restrictions on halogenated flame retardants, particularly brominated compounds, have created an urgent need for environmentally benign and high-performance alternatives in leather manufacturing. This study presents the development of a bromine-free aluminum–carboxymethyl melamine (Al-CMM) Metal–Organic Framework (MOF) as a hybrid flame-retardant system specifically engineered for leather applications. The nitrogen-rich carboxymethyl melamine ligand was synthesized and complexed with Al³+ ions under aqueous conditions to obtain a thermally stable MOF with high charforming capability. To enhance its processability and distribution, the MOF was wet-milled to sub-micron sizes and subsequently introduced into the leather matrix during the rechroming stage, ensuring uniform penetration across collagen fibrils. The treated leathers were evaluated using horizontal flammability testing, revealing a maximum reduction of 18.2% in flammability at a 9% MOF offer level, without compromising the structural integrity of the leather. SEM–EDS mapping confirmed homogeneous MOF deposition throughout the cross-section, while ICP-OES studies demonstrated efficient exhaustion behaviour. Importantly, the physical and organoleptic properties of the treated leathers - softness, fullness, tensile strength, and grain smoothness - remained comparable to conventional chrome-retanned controls, indicating that the MOF does not adversely interfere with downstream post-tanning processes. The Al-CMM MOF system thus offers a sustainable, metal–organic route to flame-retardant leather manufacture, eliminating the environmental and toxicological concerns associated with halogen-based retardants. This work contributes a viable materialschemistry–driven solution for enhancing fire safety in automotive, upholstery, and speciality leather sectors, aligning with global sustainability mandates.