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The purpose of this study is to explore a theoretical idea in relation to a body of empirical material from a reading activity involving a picturebook on shadow. The theoretical idea, sprung from variation theory, entails children's discernment through synchronic simultaneity as a key to their ability to imagine. To explore this idea, an analysis has been conducted on how 5-year-olds, in words and actions, express themselves in a reading activity involving The Black Rabbit (Leathers, 2014) in regard to discerning and imagining about shadow as a light phenomenon. Vygotsky describes children's previous experiences as a key to their ability to imagine. The results of this study imply that children's discernment in the moment, with synchronic simultaneity, appears to be another key that unlocks their ability to imagine explicit depictions in a picturebook. The results also show that when children's discernment with both synchronic and diachronic simultaneity (i.e., discernment in the moment and before the moment) is missing, their ability to imagine remains untapped, as none of the keys to their imagination, which might unlock their ability to imagine implicit depictions in a picturebook, are used. [ABSTRACT FROM AUTHOR]

In order to achieve batch production, we propose a simple and fast method to prepare leather-finished plywood. In this study, ethylene–vinyl acetate was selected as the intermediate layer to prepare EVA/polyurethane (PU) leather composites. ESEM, tensile property test and compressive property test were used to characterize the microstructure and physical-mechanical properties of the composites. The response surface method (RSM) was also used to explore the relationship between hot pressing temperature, hot pressing pressure and hot pressing time. The significance of the factors and the interactions between the two factors were determined by ANOVA, with the most significant effect being that of the temperature. The theoretical optimal hot pressing process conditions were calculated by the regression equation as a temperature of 124.4 °C, a time of 200 s and a pressure of 1.3 MPa. The surface bond strength of the test specimen measured under this condition was 1.89 MPa, it has good finishing properties and the impregnation peel strength and surface bond strength met the requirements of GB/T 15104-2021. [ABSTRACT FROM AUTHOR]

Quantifying the degree of deterioration is crucial for developing prevention strategies for archaeological leather. In this work, the morphology, chemical compositions, and physical properties of artificially aged leather samples were analyzed using a series of test methods to determine non-destructive or micro-destructive technologies for quantifying the degree of deterioration in archaeological leather. Results show that the hydroxyproline (Hyp) content of leather decreases with the increase of deterioration degree because deterioration leads to the gradual destruction of the collagen fiber network of leather. Moreover, the Hyp content of leather can be micro-destructively determined by high-performance liquid chromatography with fluorescence detection. Therefore, the determination of Hyp content is recommended to quantify the degree of deterioration in archaeological leather. [ABSTRACT FROM AUTHOR]

Vegetable tannins are environmentally friendly tanning agents. However, they generally impart a dark colour to the tanned leather and highly contribute to the organic load in wastewaters. In this study, we employed a purification protocol separately on chestnut tannin (CT) and sulfited quebracho tannin (QT) to obtain the purified fractions (PCT and PQT). These samples were characterised by GPC, 1H NMR, 13C NMR, FT-IR, and HPLC–DAD techniques and applied for tanning tests. Through the purification process, non-tannin components and smaller molecules such as gallic acid, glucopyranose, and catechin were effectively removed from CT and QT, which consequently led to the reduced moisture content, pH value, and lighter colour of purified fractions. The crust leathers processed with PCT and PQT showed desirable light shades. Moreover, the organic loads in PCT and PQT tanning wastewater were reduced by 13.5% and 19.1%, respectively, when compared to those in traditional CT and QT tanning wastewater. Additionally, the physical and mechanical characteristics of crust leathers processed with PCT and PQT were comparable to those processed with CT and QT. Thus, purification of vegetable tannins may serve as a feasible strategy for producing light-colored vegetable-tanned leather while minimizing organic pollutant discharge during the vegetable tanning process. [ABSTRACT FROM AUTHOR]

For a long time, the leather industry has considered the chromium tanning process to be the easiest and fastest way to treat raw hides and transform them into valuable products. In the last few decades, increasing attention has been paid to the potential oxidation of the trivalent chromium in tanned leather. This happens for many reasons, such as the quality of the tanning agent or the adoption of good manufacturing practices. Anyway, the main problem, which is difficult to solve, is the sensibility of the free residual chromium tanned leather, which is high enough for possible harmful activity. Given this scenario, this work proposes a solution to decrease hexavalent chromium formation by using antioxidants during the leather tanning process. In this regard, a screening work was started, to find the worst-case scenario for trivalent chromium oxidation. To do this, commercial tanning products were employed, especially fatliquoring agents, which, in some cases, are the main source that could easily react with ROS (Reactive Oxygen Species) to drive chromium oxidation. After the determination of conditions, different groups of common antioxidants were tested to analyse the antioxidation performances and their possible use in the chromium-based tanning process. The results underline the efficient action of the antioxidants studied, paving the way for some interesting perspectives to limit the drawbacks of chromium tanned leather. [ABSTRACT FROM AUTHOR]

Fruit leathers are convenient, delicious and sophisticated alternatives to natural fruits as a source of nutrients, fibers and bioactive compounds. The present study was conducted to develop new fruit leathers by adding 0.5%, 1.0% and 1.5% wild bilberry (BIPP) and blackcurrant (BCPP) pomace powders in pear leather manufactured with honey (5%), pectin (1%) and lemon juice (2.5%) as additional ingredients. The CIEL*a*b* color parameters, titratable acidity, total phenolics content, total anthocyanins content and DPPH radical scavenging activity were determined in the fruit leathers. In addition, the puncturing force, flexibility and adhesiveness of the fruit leathers were measured and sensory analysis was conducted. The results showed that the addition of pomace powders significantly decreased the lightness, chroma and hue angle and increased the titratable acidity of the fruit leathers while a* values decreased in the leathers with BIPP addition. Flexibility slightly decreased while adhesiveness significantly increased with increasing BIPP and BCPP addition level, changes that were perceived as negative in the sensory analysis. The total phenolic content increased by 2.03, 3.26 and 4.45 times at 0.5, 1.0 and 1.5% BIPP addition, respectively, while only by 1.22, 1.42 and 1.60 times at the same levels of BCPP addition. The newly developed fruit leathers could be recommended as alternative snack foods with high nutritional value and functionality. [ABSTRACT FROM AUTHOR]

Natural leather-based materials possess a combination of air permeability, wear resistance, and plasticity. However, conventional leather products have inherent limitations that make them unsuitable for unconventional applications. Therefore, it is necessary to develop new capabilities in order to overcome these limitations. In this study, we explored the conversion of regular leather into a high-strength product with hydrophobic properties through surface engineering. To achieve this, we synthesized polysiloxane-modified fluorinated waterborne polyurethane emulsions as functional coatings using emulsion polymerization. The structure and properties of the treated leathers were characterized using techniques such as Fourier transform infrared, thermogravimetry, X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. The results demonstrated that the synthesized polysiloxane-modified fluorinated waterborne polyurethane successfully penetrated and combined with the fibers of the leather, resulting in excellent hydrophobicity. The water contact angle increased to 124.3°. Furthermore, the tensile strength and tear strength of unfinished leather are 875 N and 114 N, respectively. The application of waterborne polyurethane-derived functional additives as coatings resulted in a significant increase in tensile and tear strength of the leather by 60 N and 16 N, respectively. In addition, the softness of the leather increased from 7.6 mm to 10.09 mm. Overall, the use of this functional waterborne polyurethane coating will contribute to the diversification of leather applications. [ABSTRACT FROM AUTHOR]

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This research concentrates on the developmemnt of sustainable formulation of an environmentally friendly structural composite using an innovative approach, incorporating recycled materials. The primary aim of this research is to utilize the industrial wastes as re-circulated input to make structural materials without using new raw materials. Waste plastic, tanned waste leather, and waste glass fiber-reinforced plastic (GFRP) additives. The fabrication employs the hand layup method, and the composite undergoes comprehensive characterization following ASTM standards. According to the results, the composite designation "D" emerged as the most mechanically robust, with a tensile strength of 142 MPa, flexural strength of 195 MPa, compression strength of 156 MPa, interlaminar shear strength of 45 MPa, rail shear strength of 31 MPa, and an impact energy of 4.94 J. Concerning creep behavior, the "E" designation demonstrates minimal creep strain, recording values of 0.0057, 0.0076, and 0.0123 for 5000 s, 10000 s, and 15000 s time frame, respectively. This indicated the addition of 5 vol. % of GFRP additives improved the load-bearing effect. In terms of flammability, the "E" designation exhibits noteworthy flame resistance, with a low flame propagation speed of 10.83 mm/min. Additionally, the "E" designation demonstrates stable hydrophobic behavior, revealing a minimal water absorption percentage of 0.001. This study showcases the potential of the developed composite, emphasizing its mechanical strength, resistance to creep, flame retardancy, and hydrophobic properties, positioning it as an environmentally responsible and versatile material for diverse applications. [ABSTRACT FROM AUTHOR]

This study was based on an epoxy hybrid biocomposite made of silane-treated goat tanned leather that had been toughened with treated chitosan carbohydrate polymer (CCP) and areca fiber that had been treated with silane. The objective was to examine how silane-treated CCP and a hybrid type of fiber and leather enhance the epoxy biocomposite's mechanical and impact toughness. Aqueous solution silane treatment was used to treat the fiber and tanned leather, and the hand layup method was used to create the composites. The mechanical characteristics of the composite material Areca/Leather/Areca (ALA2) with addition 1.0 vol.% of CCP results in improvements to the maximum tensile, flexural, strength and modulus, Izod impact toughness, and hardness test values of 172 MPa, 4.98 GPa, 208 MPa, 5.30 GPa, 7.0 J, and 87 Shore D. The hybrid form of fiber and leather increased the low-velocity impact maximum up to 10.5 J and 11.3 J for reinforcements that were as-received and those had been surface treated as well as introduced with 1.0 vol.% of CCP, respectively. The addition by 1.0 vol.% of CCP for the ALA staking sequence resulted in a maximum fatigue life count of 32847. The composite designation ALA2 is therefore advised for further application, and it is suggested that Areca/Leather/Areca hybrid layup sequences with silane-treated 1.0 vol.% CCP produce the best results. In both surface-treated and as-received conditions, the ALA layup sequences outperformed other composite designations. When a high impact toughening effect is required, such composite materials with higher impact toughness and toughness may be used in the defense, automobile, drone, and structural industries. [ABSTRACT FROM AUTHOR]

The utilization of leather waste (LW) in a polyurethane (PU) matrix makes a smart and novel shape stable phase change material (SSPCM). This is essential for sustainability as it reduces landfill waste after use. The PU is synthesized in bulk with a 90% yield, using biodegradable polycaprolactone diol and bio‐based polyol (castor oil), along with tolylene‐2,4‐diisocyanate. PL and PLG composites are prepared by blending of constituent components PU (P), LW (L), and poly(glycidyl methacrylate) (PGMA, G), as specified by their code names. Role of LW (hydrogen bonding and chemical crosslinking) and morphology are elucidated by FTIR and SEM, respectively. Self‐healing time (2 h), shape fixity ratios (Rf) (PL: 60–80% and PLG: 60–70%) and shape recovery ratios (Rr) (100% for both) are determined at 60°C. PLG displays faster shape recovery in water (<30 s) compared to air (>300 s). Shape stability and thermal properties of the SSPCM are examined using the temperature responsive leakage study, TGA, and DSC. This research introduces a new approach for using leather waste (LW) in SSPCM, with self‐healing and 100% Rr. This material may find application where SSPCM with high durability and flexibility is essential such as textile and footwear materials. [ABSTRACT FROM AUTHOR]

Pestil, also known as fruit leather, has emerged as a promising non‐dairy carrier for probiotics, utilizing apricots and incorporating probiotics into its formulation. This study aimed to develop a healthy snack bar by incorporating three distinct strains of probiotic bacteria, both in free and encapsulated forms, into the recipe of apricot leather. The physicochemical, bioactive, microbiological, and textural attributes of the resulting apricot pestils were evaluated over a 120‐day storage period. Fluctuations in pH (4.74–4.97) were observed during storage, whereas water activity (0.31–0.45) and moisture content (8.05%–13.40%) exhibited a decreasing trend over time. Incorporating free or encapsulated bacteria resulted in a darker surface, attributed to the intermolecular interactions between probiotics and the pestil matrix. The initial total phenolic content was highest and declined significantly during storage (52.13–291.73 mg gallic acid equivalent/100 g) (p < 0.05). Viability was found to be higher in the encapsulated forms of bacteria at the conclusion of the storage period. Overall, apricot pestil emerged as a promising matrix for viable probiotics, facilitating their delivery and hosting in both free and encapsulated forms during storage. [ABSTRACT FROM AUTHOR]

One of the most crucial components in any industrial operation is energy. However, the supply is not limitless. One of the key ingredients in cement production is energy, whose cost share ranges from 8 to 15% of overall production costs in developed nations but is much more in undeveloped nations. Therefore, the objective of this extensive research was to carry out a thorough energy conservation audit at the Sheba leather factory, located in the city of Mekelle, in the north region of Ethiopia. The specific objective of this research was to analyse the patterns of power consumption, identify energy-saving techniques, as well as to propose energy-saving recommendations for their implementation. It was obtained using primary and secondary data from the industry personnel. As a result, a total of 19 recommendations for energy saving were found and were forwarded for consideration. These recommendations have the potential to save a total of about $ 29900 annually, but their implementation would cost close to $ 15900, with a payback period of seven months. These recommendations also cover the utilities of the boiler, motors, blower, air compressors, cooling tower, and lighting. In order to lower their energy use, economic benefits are also considered. [ABSTRACT FROM AUTHOR]

For a long time, the leather industry has considered the chromium tanning process to be the easiest and fastest way to treat raw hides and transform them into valuable products. In the last few decades, increasing attention has been paid to the potential oxidation of the trivalent chromium in tanned leather. This happens for many reasons, such as the quality of the tanning agent or the adoption of good manufacturing practices. Anyway, the main problem, which is difficult to solve, is the sensibility of the free residual chromium tanned leather, which is high enough for possible harmful activity. Given this scenario, this work proposes a solution to decrease hexavalent chromium formation by using antioxidants during the leather tanning process. In this regard, a screening work was started, to find the worst-case scenario for trivalent chromium oxidation. To do this, commercial tanning products were employed, especially fatliquoring agents, which, in some cases, are the main source that could easily react with ROS (Reactive Oxygen Species) to drive chromium oxidation. After the determination of conditions, different groups of common antioxidants were tested to analyse the antioxidation performances and their possible use in the chromium-based tanning process. The results underline the efficient action of the antioxidants studied, paving the way for some interesting perspectives to limit the drawbacks of chromium tanned leather.

Abstract Vegetable tannins are environmentally friendly tanning agents. However, they generally impart a dark colour to the tanned leather and highly contribute to the organic load in wastewaters. In this study, we employed a purification protocol separately on chestnut tannin (CT) and sulfited quebracho tannin (QT) to obtain the purified fractions (PCT and PQT). These samples were characterised by GPC, 1H NMR, 13C NMR, FT-IR, and HPLC–DAD techniques and applied for tanning tests. Through the purification process, non-tannin components and smaller molecules such as gallic acid, glucopyranose, and catechin were effectively removed from CT and QT, which consequently led to the reduced moisture content, pH value, and lighter colour of purified fractions. The crust leathers processed with PCT and PQT showed desirable light shades. Moreover, the organic loads in PCT and PQT tanning wastewater were reduced by 13.5% and 19.1%, respectively, when compared to those in traditional CT and QT tanning wastewater. Additionally, the physical and mechanical characteristics of crust leathers processed with PCT and PQT were comparable to those processed with CT and QT. Thus, purification of vegetable tannins may serve as a feasible strategy for producing light-colored vegetable-tanned leather while minimizing organic pollutant discharge during the vegetable tanning process. Graphical Abstract

PT ASA is a leather tanning company. Almost 65% of the company's assets are allocated for the procurement of raw leather, which consists of goat and sheepskin. In addition to being expensive, the availability of raw leather is also very limited. The company faces a trade-off where, on one hand, the raw material is easily decayed, but on the other hand, its availability is extremely limited, and if there is not enough inventory, the production process will be disrupted. In this research, a multi-objective optimization model is developed for controlling the inventory of raw leather using the Fuzzy Goal Programming approach. The objectives to be achieved are to minimize the total inventory cost, maximize the total quantity of raw leather that meets standards, and minimize the total cost of losses due to decayed raw leather. Based on the calculations, the fuzzy goal programming membership function value is obtained at 0.9155, with a total inventory cost over the planning horizon of IDR 10,341,630,000, a total of 1,279,542 sq ft of raw leather meeting standards, and a total loss cost due to decayed raw leather of IDR 142,911,691.

Hides and skins, the main raw materials for leather industries, are traditionally preserved with sodium chloride (NaCl). Due to the excessive use of salt (around 40 to 50% w/w) in the curing process, total dissolved solids (TDS), and salinity are produced in large quantities by the soaking effluent during the leather processing. To address the resulting environmental threat from the tanneries and replace traditional curing, plant-based curing is a cutting-edge green technology. In this study, Tamarindus indica leaves were used as a combination of 5% powder + 10% salt and 10% paste + 10% salt to preserve goat skin for 28 days. The organoleptic characteristics, hydrothermal stability, moisture content, nitrogen content, and bacterial load were periodically monitored. After curing, the goatskin was processed into leather, the environmental impact of the wastewater was evaluated, and its physical and fibre strength was assessed. The TDS value, chloride content, biochemical oxygen demand, and chemical oxygen demand were reduced up to 65.62%, 69.38%, 31.08%, and 27.06% respectively. The prepared shoe-upper leather exhibited equivalent physical properties compared to the control. Scanning electron microscopy (SEM) image ensured the conformity of the fibre structure of the experimental leather with control. A significant correlation was seen among the skin preservation efficiency parameters, while the strongest correlation was (r = -0.996, p

Recycling leather waste, which accumulates in large quantities in tanneries, and producing packaging paper with improved properties reduces the environmental burden and is at the same time economically efficient. A modified fibrous mass of waste from tanned and untanned leather scraps, waste paper, and acrylic emulsion was obtained and packaging paper based on them was produced. Alkaline modification of tanned leather waste - chrome shavings - leads to an increase in the electrokinetic potential and, accordingly, the stability of the fibrous suspension, partial hydrolysis of skin collagen occurs with the formation of new polar groups, and at the same time, the degree of cross-linking of the skin increases. In the paper composition, new intermolecular bonds are formed between cellulose and skin collagen. The microstructure, elemental composition, morphology, thermal and physical-mechanical properties of modified chrome shavings and composite paper were determined. A significant improvement has been achieved in the main parameters of paper: surface density (decrease by 16-25%), breaking load and breaking length (increase by 15-23%), number of double bends (increase by 2-6 times) in comparison with paper obtained from pure waste paper, and also to a greater extent compared to paper obtained from unmodified leather waste.

For commercial leather processing, chrome tanning is the most used approach but it significantly contributes to environmental pollution. Vegetable tannins, which are large polyphenolic compounds, form strong interactions with proteins and carbohydrates, thereby enhancing the adaptability and value of vegetable-tanned leather as well as reducing environmental impact. In this study, vegetable tannins were extracted from the leaves of Guava plants (Psidium guajava) using ethanol as the solvent, facilitated by ultrasound. Extracted tannins were quantified using the Folin–Ciocâlteu reagent with ultraviolet-visible spectroscopic method. Ultrasound enhanced the extraction process producing a high yield in less time due to its mechanical, thermal, and cavitation impacts. The extracted tannins were characterized by a variety of spectroscopic techniques, including Proton (1H) Nuclear magnetic resonance, Fourier-transform infrared, and ultraviolet-visible spectroscopy. The effect of various process variables, such as temperature, solid-liquid ratio, ultrasonic power, extraction period, and powder fineness, were also investigated to optimize the extraction process. Finally, the extracted tannins were employed in leather tanning processes to assess their potential as tanning agents. The extracted tannins ensured uniform diffusion of tannins, improved thermal stability and reduced the number of tannins in effluent by 68% making it an environmentally friendly leather tanning process.

Abstract A comprehensive evaluation of collagen-based historical artifacts is crucial for the preservation and inheritance of cultural relics, necessitating interdisciplinary approaches that integrate scientific knowledge with practical expertise to develop effective conservation strategies. The present work was focused on a piece of historical leather armor housed in Turpan Museum, Xinjiang, China. SEM–EDS, XRD, ATR-FTIR, and NMR were carried out on this historical leather armor from macro and micro perspectives, mainly including morphology observation, composition analysis, structural assessment, which could provide both quantitative and qualitative insights into the deterioration of the historical leather armor. Additionally, the non-destructive sampling methods and the third-generation sequencing technology (TGS) were employed to identify a total of 13 bacterial species and 8 fungal species, and their metabolic pathways were predicted, providing guidance for preventive conservation and restoration strategies. By the present work, necessary fundamental knowledge might be provided for the effective preservation and inheritance of collagen-based historical artifacts. Graphical Abstract

The aim of this research was to assess the hazardousness and ecotoxicity of paiche leather (Arapaima gigas) dyed with natural colourants (turmeric and purple corn) versus synthetic colourants (anilines). To determine hazardousness, the methodology included the assessment of flammability, corrosivity, reactivity to H2S and HCN, toxicity from metals, and organic compounds of dyed leather. Additionally, its ecotoxicity was determined using the California red worm (Eisenia fetida) as a bioindicator through a bioassay, with treatments at 0.02, 0.04, 0.08, 0.16, and 0.20 g of leather/g of substrate, including undyed leather and a negative control in the investigation. The hazardousness analysis results indicated that leather samples dyed with both natural and synthetic colourants are not hazardous. However, the concentrations of chromium, nickel, cadmium, and lead exceed the permitted values for their use in footwear according to the European Union. Regarding ecotoxicity, the results demonstrate that acute toxicity to E. fetida is lower for natural colourants compared to synthetic colourants, where 100% mortality occurs at concentrations between 0.04 and 0.08 g of leather/g of the substrate. Concerning chronic toxicity, after 12 weeks of exposure, the tolerance concentration for undyed paiche leather is 0.035 g of leather/g of the substrate, and for leather dyed with purple corn and turmeric, it is 0.2 g of leather/g of the substrate. It is shown that the active compounds of natural colourants have a positive effect on worm survival, and it is concluded that paiche leather dyed with these colourants presents environmental advantages over leather dyed with synthetic colourants.

Environmental pollution caused by wastes generated from chrome tan is a major concern nowadays. This study aimed to develop an eco-friendly alternative tanning agent using graphene oxide (GO) based nanocomposite materials. GO was synthesized by a new approach with modification of the Hummers method. Two types of GO-based nanocomposites, GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were prepared by adding TiO2 nanoparticles and polyethylene glycol (PEG) as surface modifiers. They were successfully applied to leather tanning processes at different concentrations (2%, 4%, and 6%). Both synthesized GO, GO-nanocomposites, and the resulting tanned leathers were characterized by Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Fourier-transform Infrared Spectroscopy (FT-IR). Different physico-mechanical properties of leathers tanned with nanocomposites were evaluated and the results were compared with chrome-tanned leathers. The tensile strength of chrome-tanned leather was 223 (kg/cm) whereas the maximum tensile strength was found at 228 (kg/cm) and 233 (kg/cm) in 6% GO-TiO2 and GO-TiO2-PEG tanned leathers respectively. The environmental pollution impact of the effluents generated by the new tanning process was assessed. The COD of effluents generated from chrome tanning was 4800 ppm which was significantly reduced to 2400-1440 ppm and 2880-1920 ppm when GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were applied in leather tanning respectively. The TDS and BOD were found at 183.8 and 200 ppm in conventional chrome-tanned wastewater which were significantly reduced to the range of 47.5-18.3 and 100-50 ppm respectively in liquid wastes obtained from the GO-composite tanning process. The maximum reduction of COD, BOD, TDS, and TSS in leather waste liquid was found with the application of 2% GO-nanocomposites in tanning. The results revealed that leathers tanned with nanocomposites possess characteristic properties which were very similar to those observed in chrome-tanned leathers whereas the new tanning agents drastically reduced the intensity of pollutants in leather effluents. The application of new nanocomposites in the leather tanning process is an innovative effort. This new nanocomposite-tanning method showed minimal consequences regarding environmental pollution with the generation of less toxic effluents from the respective tanning process.

Abstract Melamine resin (MR), traditionally synthesized using melamine and formaldehyde, is widely used in the leather industry. However, the emission of free formaldehyde poses a significant challenge for conventional MR. To address the issues of aldehyde in MR, extensive research has been conducted. This paper introduces a novel aldehyde-free MR (LTSL) retanning agent synthesized using cyanuric chloride, l-lysine, and sodium sulfanilate. The chemical structure of LTSL was analyzed via Fourier transform infrared spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The presence of amino, carboxyl, and sulfonic acid groups in LTSL enhanced its storability and imparted LTSL with an amphoteric character. The isoelectric point of LTSL was optimized to reach 4.37, and LTSL exhibited an appropriate size distribution with an average particle size of 254.17 nm and achieved high absorption rates of 87.77% and 95.84% for retanning and fatliquoring agents, respectively. Consequently, the thickness rate of LTSL reached up to 37%, with no detectable formaldehyde. Notably, LTSL also demonstrated excellent physical and mechanical properties, primarily attributed to the coordination and electrostatic interactions between the chrome-tanned collagen fiber and amino/carboxyl groups in LTSL. This research presents an innovative approach for developing an aldehyde-free MR retanning agent, significantly contributing to the sustainable development of leather manufacturing. Graphical Abstract

To achieve precise grasping and spreading of irregular sheet-like soft objects (such as leather) by robots, this study addresses several challenges, including the irregularity of leather edges and the ambiguity of feature recognition points. To tackle these issues, this paper proposes an innovative method that involves alternately grasping the lowest point twice and using planar techniques to effectively spread the leather. We improved the YOLOV8 algorithm by incorporating the BIFPN network structure and the WIOU loss function, and trained a dedicated dataset for the lowest grasping points and planar grasping points, thereby achieving high-precision recognition. Additionally, we determined the optimal posture for grasping the lowest point and constructed an experimental platform, successfully conducting multiple rounds of leather grasping and spreading experiments with a success rate of 72%. Through an in-depth analysis of the failed experiments, this study reveals the limitations of the current methods and provides valuable guidance for future research. [ABSTRACT FROM AUTHOR]

A painted wooden shield from the 16th century, commonly traced back to the famous Lepanto Battle (1571), was investigated by a multi‐analytical approach to identify its manufacturing process and shed light on its cultural provenance. The typology is coherent with both the Christian and Ottoman armies and does not allow for an attribution. Radiocarbon dated the shield to two time intervals (1470–1525, 1580–1625, at 68% level of probability), compatible with the date of the Battle of Lepanto. Optical and Scanning Electron Microscopy, Attenuated Total Reflectance, External Reflection Fourier Transform Infrared, micro‐Raman and Energy Dispersive X‐ray Spectroscopy, and histochemical and shrinking temperature tests were used to characterize the artefact. The shield resulted to be made of softwood panels, covered by a stratigraphy of flax fibres, cattle skin, and a painting preparation layer of hydromagnesite. Adhesion was ensured by bone glue. Oblique, red, and cinnabar stripes alternating on the white preparation are visible on the front of the shield, whereas a homogeneous dark paint covers the back. None of the raw materials was informative by themselves, but the unusual presence of the hydromagnesite could be crossed with the geographical context, resulting in a promising outcome for future isotopic and trace element studies. [ABSTRACT FROM AUTHOR]

Releasing of large volumes of leather scraps wastes from different leather, footwear, and leather goods industries has become a major environmental pollution concern now a days in developing countries. Natural nanofibers are widely used as prospective reinforcement materials in formulation of different biocomposites materials. Herein, a new nanocomposite material has been synthesized and characterized using leather scraps wastes and Slender amaranth based nano-cellulose with latex in a clean environment perspective. Nano-cellulose was extracted from Slender amaranth vegetable wastes as natural fiber for green composites preparation. The extracted nanofibers, leather waste composite, and the resulting nanocomposite material have been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Field emission scanning electron microscopy (FESEM). Different physio-mechanical characteristics of nanocomposite were evaluated which showed its potential applications as shoe upper components. The results revealed that addition of nano-cellulose significantly improved the physical properties of new composite sheet. SEM images revealed the surface morphology of nanocomposite which was observed to be predominantly homogenous with uniform distribution of particles. This novel nanocomposite exhibits different potential properties and TGA data showed higher thermal stability of this material in comparison to those obtained with control method. It can find application as a green reinforcement material in the preparation of different leather goods with improved mechanical properties and thermal stability. These significant findings highlight the preparation of a valuable biocomposite material from leather solid wastes which is cost effective and sustainable for leather industries as well as it emphasizes an effective approach to reduce environmental pollution. [ABSTRACT FROM AUTHOR]

Polyurethane acrylates (PUA) are commonly used as leather finishing agents because of their excellent film-forming, mechanical and abrasion resistance properties. In this study, silicone-modified polyether-based waterborne polyurethane acrylate (WPUA) was synthesized as an environmentally friendly leather finishing agent. The effects of different soft segments on the properties of WPUA were investigated by tensile strength, water absorption, thermogravimetry (TG), derivative thermogravimetry (DTG), and water contact angle tests. The results showed that the WPUA synthesized with PTMG 2000 as the soft segment had higher elongation at break, lower water absorption, and a larger water contact angle. The effect of different mass percentages of silicone on the properties ofpolytetramethylene oxide (WPUA) was investigated by scanning electron microscope (SEM), particle size, zeta potential, Fourier transform infrared spectroscopy (FT-IR), water contact angle, folding resistance, and mechanical properties. It was found that the hydrophobic, tensile, and folding resistance properties of the waterborne leather finishing agent were best when the silicone content was 5 wt%. What's more, the synthesized silicone-modified polyether-type waterborne polyurethanes, with excellent comprehensive performance, have great potential for industrial application in leather finishing agents. [ABSTRACT FROM AUTHOR]

The aim of this study is the determination some quality parameters of grape and mulberry pestils (leathers) sold in Elazig. For this purpose, a total of 45 fruit pestil samples, of which 23 were grape pestils and 22 were mulberry pestils, were analyzed for their physical properties, chemical properties, and microbiological characteristics. In grape and mulberry pestils, the average L* (lightness/darkness) values were 42.72 and 44.81, a* (redness) values were 10.29 and 9.07, and b* (yellow) values were 20.90 and 20.90, respectively. In grape and mulberry fruit pestil samples, the thickness values were 1.62 and 1.34, pH values were 3.82 and 4.75, acidity values (as citric acid) were 0.63 and 0.22%, aw values were 0.602 and 0.627, dry matter values were 68.78% and 72.99 %, ash values were 2.25% and 0.64%, insoluble ash values in 10% HCl were 0.20 and 0.29, and Brix values were 18.83 and 19.36, respectively. TMAB, coliform, Staphylococcus-Micrococcus, and yeast-mold counts were found to be 4.72 and 4.48, 1.30 and 1.89, 2.11 and 2.12, and 2.04 and 2.11 log10 cfu/g, respectively, in all samples examined. In 14 of the samples (31.11%), the total number of mesophilic aerobic microorganisms was found to be >5 log10 cfu/g. Escherichia coli and Salmonella spp. were not found in any of the samples. However, the samples were found to contain significant levels of yeast-mold. There was no difference between the groups in microbiological terms in statistical analysis (P > 0.05). According to the current study, there was no standard production and not enough hygiene rules were observed in the pestil production process in family businesses in Elazig. On the other hand, essential information was obtained on some physical, chemical and microbiological quality parameters of grape and blackberry pulps sold in markets and stores in Elazig. [ABSTRACT FROM AUTHOR]

The current review context elaborates on the engineering methods adopted by the researchers for the development of different sustainable flexible composites for use as an alternative to leather like material. This article also elaborates on the usage of different natural fibre-based cellulose, bacterial cellulose, and different plant-based compounds for the construction of leather like lifestyle products with the examination report of essential physical properties of engineered products. Besides, it elucidates the process conditions followed by the researchers for making natural fibre based flexible composite products. [ABSTRACT FROM AUTHOR]

Flexible heaters with personal thermal management capabilities have great potential in thermal therapy applications due to their excellent flexibility, low power consumption, and portability. However, manufacturing wearable heating devices that are breathable, wear resistant and conformal for long-term use is still challenging. To address these issues, we designed a leather heater using breathable, biocompatible, and tailorable leather as the substrate through a simple in-situ polymerization polypyrrole strategy. This heater exhibits excellent heating and mechanical properties (reaching 64°C at a voltage of 5 V with efficient Joule heat generation of 2286 W/m2 and uniform temperature distribution, and functioning properly after 1000 cycles of bendability tests). In addition, this heater displays better wear resistance and water vapor permeability rate (38.04 g/(m2 h)). The cuttable and sewable of leather gives the strategy ability to be flexibly designed to mold the heater to the specific requirements of different body parts, providing a new approach to wearable thermal therapy. [ABSTRACT FROM AUTHOR]

Formaldehyde is widely utilized across various industries such as food, textiles, and leather, yet its presence raises significant health concerns due to its irritation and carcinogenicity. Numerous methods have been developed to probe it in solution and gas states. Among them, absorption spectroscopy-based methods commonly employed. However, these methods require complex preprocessing for colored solutions to avoid interference. In response to this challenge, a novel interference-resistant detection kit leveraging surface-enhanced Raman spectroscopy (SERS) coupled with reaction-induced self-amplification for rapid and direct detection of formaldehyde was developed. The kit needed only ten minutes and achieved a limit of detection lower than 10−4 μg/mL with a handheld Raman spectrometer. Thanks to the kit's reaction with formaldehyde, colloidal nanoparticles were linked to form "hot-spots" to further enhance the SERS signals. The signal demonstrated outstanding resistance to interference, including different dyes, ensuring a practical tool for direct detection of formaldehyde in complex solutions. [ABSTRACT FROM AUTHOR]

AbstractLeather finishing provides an esthetic look to the leather. Oil in combination with wax emulsion in the form of oleogel when applied to leather finishing produces a special class of leather known as crunch leather. Using an optimized ratio of Beeswax emulsion blended with Neat’s-foot oil in the form of oleogel for the making of crunch leather was investigated in this study. The chemical characterizations such as FTIR, dynamic light scattering, and particle size analysis, of the experimental emulsion were carried out. The experimental leathers undergo various tests such as contact angle measurements, optical microscopy imaging, color measurement, light fastness, fastness to dry and wet rub, tensile, tear strength, and elongation at break. The experimental leathers were showing better results than the control leathers. The present work focuses on the finishing of leather, and the interaction of oil and wax oleogel with leather which approaches a sustainable and eco-friendly process. [ABSTRACT FROM AUTHOR]

1. The aim of this study was to estimate heritability and genetic correlations, first among behavioural responses of juvenile South African Black ostriches towards humans and secondly with slaughter weight and skin traits.2. Behavioural traits, such as willingness of the birds to approach humans, keeping a distance from the human observer and allowing touch interactions by a human were recorded (n = 1012 birds). In addition, slaughter weight, skin size, scores for nodule size, nodule shape and the presence of hair follicles were recorded.3. Single- and multi-trait animal model analyses performed on the data using ASReml4 revealed high heritability estimates of 0.44 for allowing touch interactions and 0.48 for both willingness to approach and keeping a distance from the human observer. In addition, significant genetic correlations among behavioural response traits were estimated, ranging from −0.99 between keeping a distance and willingness to approach the human observer, to 0.87 between allowing touch interactions and willingness to approach the human observer.4. In contrast, genetic correlations of behavioural response traits with most slaughter and skin traits were low, variable, and not significant. The exception was hair follicle score, which appeared to be unfavourably correlated with key behavioural traits.5. This study suggested that the temperament of ostriches could be improved by selection of birds that demonstrate willingness to associate with humans without compromising slaughter weight or skin traits. [ABSTRACT FROM AUTHOR]

PET/PA6, hollow, segmented-pie, microfiber nonwovens (PET/PA6 HSMNs) play an important role in a microfiber, synthetic leather base. Most of the current PET/PA6 HSMNs generally lack in hygiene performance. Moreover, there is an urgent need for the asymmetric wettability of PET/PA6 HSMNs to ensure the comfort of clothing. In this work, a novel, asymmetrically wettable, PET/PA6 HSMN with a gradient structure is proposed, which can regulate liquid adsorption and directional transport. An MOF-303 was successfully synthesized and loaded onto the PET/PA6 HSMN, which had been pre-treated with gradient hydrolysis under sulfuric acid. The droplet quickly permeated the modified PET/PA6 HSMN, and the droplet disappearance time decreased to 62.40 ms. The liquid strikethrough time of the modified PET/PA6 HSMN reached 5.16 s. The maximum adsorption capacity of the modified PET/PA6 HSMN was 68.161 mg/g, which was improved by 122.83%. In addition, the air permeability of the pre-treated PET/PA6 HSMN increased from 308.70 mm/s to 469.97 mm/s, with the sulfuric acid concentrations increasing from 0% to 20%, and the air permeability of the modified PET/PA6 HSMN decreased gradually from 247.37 mm/s to 161.50 mm/s. Furthermore, the tensile strength of the modified PET/PA6 HSMN treated with sulfuric acid and MOF-303 was also obviously enhanced compared with the PET/PA6 HSMN treated with pure sulfuric acid. This PET/PA6 HSMN, with asymmetric wettability, owing to its high hygiene performance and water transport capabilities, is promising and able to extend the application of a microfiber synthetic leather base for clothing. [ABSTRACT FROM AUTHOR]

Tefillin are Jewish ritual artifacts consisting of leather cases, containing inscribed slips, which are affixed with leather straps to the body of the tefillin practitioner. According to current Jewish ritual law, the tefillin cases and straps are to be colored black. The present study examines seventeen ancient tefillin cases discovered among the Dead Sea Scrolls in caves in the Judean Desert. All seventeen cases display grain surfaces with a very dark, nearly black appearance. We start with a hypothesis that the cases were intentionally colored black in antiquity using either a carbon-based or iron-gall-based paint or dye. The aim of this study is to test this hypothesis by subjecting these tefillin cases to a battery of examinations to assess the presence of carbon and iron used as pigments, and of organic materials which may have been used as binding agents in a paint. The tests deployed are: (1) macroscopic and microscopic analyses; (2) multispectral imaging using infrared wavelengths; (3) Raman spectroscopy; (4) Fourier transform infrared spectroscopy (FTIR); and (5) scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy. The results of these tests found no traces of carbon-based or iron-gall-based pigments, nor of organic compounds which may have served as binders in a paint. These results suggest that our posited hypothesis is unlikely. Instead, results of the SEM examination suggest it more likely that the black color on the surfaces of the tefillin cases is the result of natural degradation of the leather through gelatinization. The Judean Desert tefillin likely represent tefillin practices prior to when the rabbinic prescription on blackening tefillin was widely practiced. Our study suggests that the kind of non-blackened tefillin which the later rabbis rejected in their own times may well have been quite common in earlier times. [ABSTRACT FROM AUTHOR]

The fragility and weakness of historical, archaeological, and heritage leather artifacts in museums, and libraries due to unsuitable environmental conditions are significant challenges. This study aims to assess the effectiveness of Hydroxypropyl Beta Cyclodextrin, a novel material, in consolidating leather artifacts by examining their physical, chemical, and mechanical properties. Vegetable-tanned leather samples were treated with different concentrations of Hydroxypropyl Beta Cyclodextrin and subjected to artificial heat aging. Evaluation methods included digital and scanning electron microscopy, contact angle measurements, mechanical testing, color analysis, pH measurement, and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy. Results showed that Hydroxypropyl Beta Cyclodextrin at 1% and 2% concentrations improved chemical stability, surface morphology, color retention, and mechanical properties of the leather samples. The third concentration yielded less favorable outcomes. This study recommends using Hydroxypropyl Beta Cyclodextrin at 1% and 2% concentrations for consolidating historical leathers. [ABSTRACT FROM AUTHOR]

Due to the increase in electromagnetic waves emitted by the electrical and electronic equipment surrounding us, protection from electromagnetic waves has become a very important subject. It is thereby proposed that conductive textiles and fabrics are used for protection of sensitive equipment and personnel from electromagnetic interference. Conductive textiles are considered to be a particular sub-genre of technical textiles and exhibit favourable electromagnetic shielding properties together with a list of other attributes that make them suitable for such applications. In more detail, conductive textiles exhibit light weight and low volume while being comfortable to wear, conforming to different shapes of surfaces and everyday objects (thus being easily integrated within the surrounding environment), being aesthetically appealing, etc. In this context, most of the literature-available shielding textiles or fabrics used are either conventional or conductive fabrics that are further coated with metal layers for extra conductivity and shielding. However, metal shielding exhibits certain disadvantages: it is prone to corrosion while corrosion-resistant materials (such as silver or gold) are extremely expensive; it is difficult to process; and it compromises the comfortability and aesthetic appeal of the final product. Herein, we propose the usage of electrically conductive leather for efficient shielding from electromagnetic interference. The motivation for this work is twofold: first, leather materials are seldom if not at all used for electromagnetic shielding and we wanted to close that gap for an industry sector (leather clothes and garments) that is thriving. Second, we are using one or more layers of polypyrrole treatment (PPy) to inherit conductivity to leather surfaces. We show that PPy is sufficient treatment for inheriting very satisfactory electromagnetic shielding properties all the while maintaining the comparative advantages of a non-metal-processed fabric surface (e.g. comfortability, aesthetic appeal etc.). We demonstrate a variety of different PPy treated leather samples and illustrate that electromagnetic shielding is proportional to the number of PPy layers used for leather processing. The measurements results are obtained using RF and microwave high-frequency equipment in a controlled laboratory environment within the X-microwave band (8-12 GHz). [ABSTRACT FROM AUTHOR]

The conventional use of chemicals worldwide in different industries has significantly increased, impacting the environment. The need to improve industrial processes led to prospects into enzymes from various sources, including microbial sources to substitute the toxic chemicals and processes with environmentally friendly processes and biodegradable waste products. Enzyme applications are notably getting more attention in medicine, agriculture, and industries, including pharmaceuticals, food, detergents, leather, and cosmetics. They are utilized in these industries to enhance durability of product, shorten process time, improve efficiency and stability, and properly manage waste. Medicine mainly uses them for diagnostic and treatment purposes, including proteases and amylases. The pharmaceutical industries explore the specificity of enzymes to bind target substrates, yielding specific and desired products via reactions, including hydrolysis, acylation, and esterifications. Waste and pathogen treatments, in addition to soil and plant improvements, are the major applications of enzymes in agriculture, employing pectinases, cellulases, and xylanases. In the food industry, amylases are used for starch degradation and dough improvement, whi le proteases are used for juice beer production clearance. The detergent industry adds enzymes to its formulations, including lipases, proteases, and cellulases, to improve stain removal by modifying fabric fibers to release dirt and soil particles. Enzymes, including proteases and lipases, are used in the leather industry for curing, soaking, dehairing, degreasing, and tanning, in addition to waste elimination. In comparison, an immobilized lipase is utilized in the cosmetic industry to produce retinoids, protein disulfide isomerase, glutathione sulfhydryl oxidase, and transglutaminase are applied in hair waving. Furthermore, developing the cost-effective technique of enzyme immobilization technology further promotes the application of enzymes in these endeavors attributed to their stability and recyclability. Thus, there is a significant improvement in research towards green and eco-friendly applications of enzymes. This review discusses how enzymes have been successfully deployed and utilized in medicine, agriculture, pharmaceutical, food, detergent, leather, and cosmetics industries. Enzymes in these industries exhibited beneficial applications, though the recyclability of the enzymes remains challenging for some endeavors. However, immobilization techniques have been gaining attention which might present a solution to the challenges associated with enzyme reusability. [ABSTRACT FROM AUTHOR]

As a global research topic, leather artifacts have been studied even longer than other materials. And the archaeology and research on them is more abundant in foreign countries. The technology of leather manufacturing, an ancient craft, has a long history of development, and can be traced back to the Paleolithic Age, which is almost as long as the history of human civilization. Therefore, the study of leather artifacts and their historical development is of great significance to the restoration and protection of leather artifacts. After reviewing earlier literature and books, this paper had a preliminary understanding of the unearthed situation and status of ancient leather abroad. With further reading, it finally analyzed and summarized the unearthed leather artifacts from nearly 39 regions of five continents. The structure of this paper is composed of three aspects: the situation of foreign leather artifacts, the characteristics of cultural relics and the leather tanning techniques. Firstly, it analyzed and summarized typical archaeological sites with abundant resources such as the Austrian salt mine, Danish marsh, Rome leather factories in Europe, Asia, Africa and so on, to understand the time, burial environment and uses of unearthed leather artifacts, so as to analyze the tanning process. Europe is rich in unearthed artifacts dating back to prehistoric times, including Iron Age hide fragments from the Italian ice fields, prehistoric hide fragments of shoes from the Swiss ice fields, and more than 200 Iron Age hides from the Hallstatt salt mine in Austria. The Pazyryk tombs of the Iron Age in the Altai Mountains of Asia provide important information for understanding the natural beast art style of the Altai Mountain areas. Egyptian leather, affected by the Nubian culture in Africa, is rich in colors and materials. Through reviewing the history and development of ancient leather in many areas, this paper further analyzed the tanning process, which could provide clues and information for the protection of ancient leather artifacts. Secondly, the ages of leather artifacts were divided into Neolithic Age, Bronze and Iron Age, A.D. to the 5th century A.D., and Middle Ages, and the characteristics of leather artifacts in different ages were analyzed by taking study areas as examples. For instance, in the Neolithic period, people used the serrated edges of stones and cherts to cut animal skin, and stitched leather with bone needles, bone spurs or plant fibers. The leather that Otzi the icaman wore in the late Neolithic period was made of animal tendons sewn by plants as stitches, which confirmed the characteristics of this era. Finally, the ancient leather tanning techniques were mainly plant tanning, mineral tanning, smoke tanning and oil tanning. Through understanding the leather artifacts of 39 regions, the characteristics of ancient tanning process were analyzed and compared. The result of the tanning process depends on a number of factors, such as the type of hides (bull or cow hides), breeds (cow or sheep leather), living conditions (animals’ health condition), the quality of the raw hides, the properties of different parts of the same hide and the tannin. With the plant tanning as an example, the source of plant tannins and the differences in functional groups in tannins affect the efficiency of tanning and the properties of tanned leather. Based on the published literature on leather artifacts, this paper widely collects, collates and analyzes the distribution of foreign leather artifacts and their characteristics, and summarized four ancient leather tanning techniques. Sorting out the relevant data of leather artifacts in 39 regions and understanding the human living environment and cultural history can help further study the development of leather in the context of the times. The study of various uses of leather can enrich the development of leather tanning technology, and research on tanning technology and tannins used is of great significance for the restoration and protection of leather artifacts. The tanning process of many unearthed leather artifacts is hard to determine. Thus, the analysis of four ancient tanning processes summarized by predecessors is emphasized in this paper to compare the differences between tanning techniques. The aim is to determine the tanning method of unearthed leather artifacts with more advanced and non-destructive technology and methods and to fill the gap of tanning information of leather artifacts for the protection and restoration. And this paper clarifies the development characteristics of the world leather artifacts and provides a reference to enhance the international study level of leather artifacts in China. [ABSTRACT FROM AUTHOR]

The research presented here is an attempt to develop an innovative and environmentally friendly material based on bacterial nanocellulose (BNC), which will be able to replace both animal skins and synthetic polymer products. Bacterial nanocellulose becomes stiff and brittle when dried, so attempts have been made to plasticise this material so that BNC can be used in industry. The research presented here focuses on the ecological modification of bacterial nanocellulose with vegetable oils such as rapeseed oil, linseed oil, and grape seed oil. The effect of compatibilisers of a natural origin on the plasticisation process of BNC, such as chlorophyll, curcumin, and L-glutamine, was also evaluated. BNC samples were modified with rapeseed, linseed, and grapeseed oils, as well as mixtures of each of these oils with the previously mentioned additives. The modification was carried out by passing the oil, or oil mixture, through the BNC using vacuum filtration, where the BNC acted as a filter. The following tests were performed to determine the effect of the modification on the BNC: FTIR spectroscopic analysis, contact angle measurements, and static mechanical analysis. As a result of the modification, the BNC was plasticised. Rapeseed oil proved to be the best for this purpose, with the help of which a material with good strength and elasticity was obtained. [ABSTRACT FROM AUTHOR]

The leather industry is one of the most polluting industries in the world due to the large amounts of waste following raw hide processing but also due to the high content of chemical substances present in leather waste. The main problem with chromium-tanned leather solid waste is related to the storage, due to the ability of chromium to leach into soil or water, and also owing to the high ability of trivalent chromium to oxidize to its toxic form, hexavalent chromium. The purpose of this article is to present the most current methods of chromium extraction from solid tanned leather waste in order to obtain non-polluting leather, which can constitute secondary raw material in new industrial processes. The extraction methods identified in the present study are based on acid/basic/enzymatic hydrolysis and substitution with the help of organic chelators (organic acids and organic acid salts). In addition, this study includes a comparative analysis of the advantages and disadvantages of each identified extraction method. At the same time, this study also presents alternative chromium extraction methods based on the combination of conventional extraction methods and ultrasound-assisted extraction. [ABSTRACT FROM AUTHOR]

The progress of chrome-free tanning in tanning has made the development of its supporting polymer chemicals a hot spot. In terms of polymers, the structure of polymer chains has a significant impact on their molecular structure, directly affecting their application range and effectiveness as the leather chemicals in this process. To date, there are still few reports on the review of organic chromium-free tanning chemicals based on the structure of polymer chains. Thus, in this study, the polymer chemicals used in chrome free tanning was reviewed according to the main construction methods such as linear, branched, and cross-linked structures. In addition, the characteristics of the different configurations, the main factors affecting them and the advantages of the corresponding configurations in the preparation of chemicals for chrome-free tanning were characteristics. This study can provide theoretical supports for the development of polymer chemicals in organic chromium-free tanning systems, and further promote the transformation, upgrading, and sustainable development of the traditional leather industry. [ABSTRACT FROM AUTHOR]