Abstract

Researchers have pointed out that the upper part of therapeutic footwear should be made from leather or a combination of materials with a smooth inner lining. This study aims to evaluate the quality of shoe upper leather made based on environmental considerations for therapeutic footwear manufacture, specifically for individuals with diabetes. The leather utilised in this research is vegetable-tanned, a more sustainable and environmentally conscious alternative to conventional chrome tanning methods. Sixteen (16) different tannin ratios of Divi-Divi (DD), Acacia nilotica (AN) and Pakia clappertoniana (PC) were explored to enhance the resultant leather. The tanning trials were conducted with a 30% blend for shoe upper leather. Important physical properties determined following the official methods of the International Union of Leather Technologists and Chemist Society (IULTCS) include tensile strength, elongation at break, Lastometer, Apparent density, Indentation index, resistance to compression, water vapour permeability, water vapour adsorption and shrinkage temperature. The findings revealed that tannin ratio B4 (PC:DD (3:1)) produced the highest shrinkage temperature at 85°C, while tannin ratio B2 (PC:DD (1:1)) exhibited the highest resistance to compression at 6.65 N/mm², a low water vapour permeability of 0.12%, and an elongation of 52%. Tannin ratio B3 (PC:DD (1:3)) displayed water vapour adsorption of 13.5%, an apparent density of 5.63 kg/m³, and tannin ratio A1(DD) demonstrated an indentation index of 37, and a tensile strength of 33.2 N/mm². The results of the Lastometer test exceeded the standard value of 7 mm distension. The outcomes suggest that the vegetable-tanned leather utilised in eco-friendly therapeutic footwear exhibits comparable physical properties to traditional chrome-tanned leather commonly used in the footwear industry. In conclusion, this study posits that vegetable-tanned leather can serve as a viable, eco-friendly alternative to traditional chrome-tanned leather in producing therapeutic footwear for individuals with diabetes while maintaining quality standards.