Gelatine-modified Zn-Al layered double hydroxide (GLDH) was synthesised by co-precipitation to develop an effective, environmentally compatible flame-retardant system for leather. The resulting GLDH and the precursor materials (gelatine and Zn-Al LDH) were characterized by zeta potential, hydrodynamic diameter, crystallographic phase(s), functional groups, and thermal analysis. The GLDH exhibited crystallographic phases typical of LDH, gelatine, and hydrozincite (ZnO), confirming the successful incorporation of gelatine in the LDH matrix. Pristine LDH and GLDH were applied to leather to assess their influence on the flammability performance of leather. Horizontal flammability tests showed a reduction in burning rate by 9.1% for LDH-treated leather and 23.5% for GLDH-treated leather. The enhanced performance of GLDH is attributed to the synergistic effect of gelatine incorporation, which promotes char formation and improves thermal shielding in addition to the endothermic dehydroxylation and decomposition mechanism of the LDH. These results indicate that gelatine-modified LDH can be a promising, environment-friendly flame-retardant additive for leather.
Crunch leather is a special class of leather that exhibits a double-tone effect on the surface due to the migration of oil within the leather surface. In this study, extracted fat has been used in place of oil to get crunch leather. The fat was extracted from cow, buffalo, sheep, and goat and characterised. Due to high fat content, sheep fat was specifically selected for use in the finishing process as an alternative to traditional oils in the making of crunch leather. The experimental leather preparation involved mixing sheep fat with a Beeswax emulsion at 80 degrees C in varying ratios. These experimental leathers were compared with control leathers treated with carnauba wax to assess differences. The physical properties of the experimental leathers were found to be on par with those of the control leathers.
In the quest for eco-friendly and sustainable substitutes for traditional petroleum-based polyurethane (PU) dispersions for leather finishing, this work explores the application of bio-based waterborne polyurethane dispersion (BPUD) prepared from cardanol-based polyols for typical resin finishing in comparison to the performance of a commercial petroleum-based PU dispersion (PPUD). Two formulations were studied namely a mixture of BPUD with an acrylic resin binder at 1:1 ratio and the other using BPUD alone (2:0 ratio) and various performance properties such as film adhesion, color fastness, water vapor permeability, hydrophobicity, and gloss were analyzed along with structural properties. Physicochemical characterization showed that BPUD has a lower particle size and similar viscosity compared to PPUD. The structural features of the leather, namley grain surface and fiber structure, were not altered significantly when PPUD is substituted with BPUD as seen through scanning electron microscopy. Most importantly, BPUD exhibited better film adhesion in dry and wet environments, increased water vapor permeability (4.9 mg/cm(2).Hr compared to 3.09 mg/cm(2).Hr for PPUD based finishing), and matching hydrophobicity and gloss, especially in the resin-free variant. Color fastness against rubbing and light was slightly lower in the absence of resin, but total performance confirms the viability of BPUD as a good petrochemical-based PU alternative. These results highlight the significance of bio-based dispersions in environmentally friendly leather processing and pave the way for the continued development of biodegradable and sustainable PU systems.
Traditionally, 50% w/w sodium chloride (NaCl) is employed for hides and skin preservation (curing). However, enormous water pollution, aquatic toxicity, soil infertility, and high chemical consumption make it questionable. Leftover and abundant plant biomass can be a sustainable alternative source of curing if they keep antimicrobial activity against hides and skin spoilage microorganisms. This study investigates biomass-based curing (BBC) from Cynodon dactylon and Albizia lebbeck plant independently and collaboratively. The plant's dry powder was directly applied and evaluated curing efficiency through bacterial load, moisture content, hydrothermal stability, and hydroxyproline content assessment. The BBC formulations were easy to use and showed high biomass conversion efficiency, reaching 41% for C. dactylon and 53% for A. lebbeck based on raw weight. They also exhibited strong antimicrobial activity. C. dactylon showed inhibition zones of 18 mm against E. coli and 17 mm against B. subtilis in methanol extracts. A. lebbeck showed a 17 mm zone of inhibition against E. coli in both ethanol and methanol extracts, and a 15 mm zone against B. subtilis in ethanol extract. In addition, the BBC formulations successfully preserved goatskin for 30 days, performing comparably to the conventional preservation method. It lessened the salinity, total dissolved solids, and chemical oxygen demand load from tannery-soaking effluent by 67-74%, 41-65%, and 60-85%, respectively, through the maximum reduction of salt consumption (90%). The environmental efficiency index (EEI) revealed that BBC systems (EEI: 29.9-31.3) are around 1.5 times more environmentally sustainable than conventional curing (EEI: 20.7). In addition, the alternatives have no effect on the features of final leather. Therefore, the ecofriendly BBC has the potential to prevent the generation of heavy pollution from tanneries.
Diabetic foot (DF) disease can involve both monomicrobial or polymicrobial infections. The emergence of antibiotic-resistant strains in DF has been attributed to the recurring nature of infections and the use of antibiotics by patients. In some cases, these strains have been observed to form biofilms, which can significantly complicate the progression of the disease. Shoes are very important for patients of DF. In this regard, the importance of natural compounds that can be integrated into shoes/insoles that DF patients can use is emphasized in the literature. Lichens have very important bioactive components that are not even found in plants, and these compounds have many properties such as antimicrobial, antibiofilm and antioxidant. This study aimed to investigate antibacterial, antibiofilm and antioxidant properties of acetone extracts obtained from tested lichens against DF isolates. The lichen species examined were P. furfuraceae, H. physodes, and Usnea spp., and the isolates analyzed included S. epidermidis, A. baumannii, A. pittii, P. aeruginosa and K. pneumoniae, which were isolated from DF patients. Lichen acetone extracts were found to have low antibacterial activity (below 50% inhibition) against only A. baumannii and S. epidermidis. However, with consideration of the antibiofilm effect of the extracts, a more promising outcome was observed than in terms of antibacterial activity. Noteworthy antibiofilm activity was exhibited by lichen extracts, particularly against S. epidermidis (approximately 97%) and subsequently against A. pittii (between 92.61- 80.59%) at the 800 mu g/mL. Even at a concentration as low as 25 mu g/mL, the acetone extracts of P. furfuraceae, H. physodes, and Usnea spp. inhibited biofilm formation of S. epidermidis, with inhibition ratios of 92.95%, 94.74%, and 96.43%, respectively. Moreover, high biofilm inhibitory effects with the percentages of 87-90% were detected against K. pneumoniae even at low concentrations. The findings of this study demonstrate that acetone extracts from the tested lichen species exhibited a high antibiofilm efficacy of over 80% against DF isolates. It is important to consider the capacity of lichens to prevent the formation of biofilms by microorganisms that develop on the feet of diabetic patients. The incorporation of these materials into footwear in the leather industry may provide an additional benefit of combating persistent microorganisms.
