Physical, mechanical and chemical characterization of a composite from leather shavings and scrap office paper for potential packaging application

A composite material with potential applications in the packaging industry was developed using leather shavings, scrap office paper, thermoplastic resin, and distilled water. The production process consisted of raw material preparation, the production of recycled paperboard sheets, and sheet finishing. An extreme vertex mixture design generated 13 samples to optimize the proportions of paper, leather shavings and resin, using tensile strength (ASTM D828-22) as the dependent variable. The optimal recycled paperboard formulation was 70 wt.% paper, 5 wt.% leather shavings, and 25 wt.% resin. Physical tests were conducted to measure grammage (ISO 536), thickness (ISO 534), moisture content (TAPPI T 412), and water absorption (ISO 535-2023). Chemical analyses included scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) with attenuated total reflectance (ATR), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG) and elemental chemical composition of the composite material. Compared with reference paperboard, the recycled paperboard exhibited lower moisture absorption but also reduced tensile strength. FTIR spectra confirmed cellulose-related bands and revealed the presence of collagen from leather, while TGA/DTG curves indicated slight shifts in degradation temperatures, reflecting reduced thermal stability due to leather incorporation. The recycled paperboard shows potential for sustainable packaging applications that demand moderate mechanical performance. However, the lower thermal stability and tensile strength may limit its use in high-stress demanding applications. • Discarded scrap office paper, leather shavings, and thermoplastic resin were used. • Physical, mechanical, and chemical tests were carried out on the recycled paperboard and reference paperboard. • Water absorption was reduced by 22.94% compared with reference paperboard.