2024 Vol.34(5): 1–7    [Abstract] ( )    [PDF 1462 KB ] ( )

Odor problems in leather-making processes have received more and more attention with increasing environmental awareness among the populace. However, there is currently a lack of systematic research and a summary on the sources, causes, and control methods of odor from the leather-making processes. A three-round Delphi survey was conducted to study the odor levels and sources of the leather-making processes by consulting 51 experts from leather-making enterprises, industry associations, and universities in the leather field. Results show that the odor in the leather-making processes mainly comes from seven procedures and the odor levels of these procedures, from high to low, are storage, unhairing, liming, soaking, fleshing, deliming, and splitting. The main odorous substances are odorous gases generated by decaying hides or hide scraps in the rawhide warehouse, fleshing and splitting machines, and ground gaps; odor of industrial sulfide impurities; and ammonia and hydrogen sulfide released from ammonium salt deliming. It is recommended that tanneries prevent and control odor pollution by inhibiting rawhide decay; keeping fleshing machine, splitting machine, and tannery ground clean; adopting low-sulfide hair-save unhairing and ammonia free deliming technologies; and spraying deodorants.

2024 Vol.34(5): 8–14    [Abstract] ( )    [PDF 1617 KB ] ( )

Industrial wastewater frequently contains priority pollutants like chromium, which tend to form complexes with organic molecules. These complexes are challenging to remove, often leading to substantial environmental discharge. In this study, Selenastrum capricornutum served as the model organism to investigate the biological impact of various multiligand chromium complexes on algal cells. Results showed that the multiligand chromium complexes significantly elevated the level of reactive oxygen species (ROS) in the algal cells (increases of 44% to 55%), which induced oxidative stress and consequently inhibited algal growth to different extents (inhibition rates ranged from 16% to 67%). Extended exposure further hindered the synthesis of soluble proteins and carbohydrates in Selenastrum capricornutum. Notably, gelatin-gallic acid-chromium complexes were identified as the most biotoxic of the multiligand chromium complexes studied. Furthermore, Selenastrum capricornutum exhibited some degree of biodegradation of these complexes after long-term co-cultivation. These findings suggest that multiligand chromium complexes could pose considerable risks to aquatic ecosystems.

2024 Vol.34(5): 15–24    [Abstract] ( )    [PDF 2439 KB ] ( )

The development of biodegradable plastics holds significant importance and value in achieving carbon peaking and carbon neutrality goals. Utilizing gelatin as the raw material, gelatin films were produced through a combination method involving plasticizing with nonanoic acid, crosslinking with dialdehyde starch, and hot pressing. Investigation was conducted to explore the effects of nonanoic acid plasticizing and hot pressing on the structure and performance of dialdehyde starch-crosslinked gelatin films. Results indicate that, when a 20% addition of nonanoic acid was made, the modified gelatin films exhibited a smooth surface, dense structure, the highest tensile strength, and lower rates of elongation at break, water vapor permeability and swelling properties. After 11 minutes of hot pressing, the gelatin film demonstrated improved water resistance and mechanical properties. It maintained a relatively intact film morphology after 22 days of degradation in soil, and over 80% mass loss after 34 days. The gelatin films prepared through nonanoic acid plasticizing, dialdehyde starch crosslinking, and hot pressing, with high mechanical strength, water resistance and environmental degradability, are offered beneficial strategies for the development of environment-friendly protein plastics.

2024 Vol.34(5): 25–31    [Abstract] ( )    [PDF 1621 KB ] ( )

Using gelatin as the raw material, a homogeneous solution was prepared by dissolving it in a ternary system of sodium acetate trihydrate/urea/water (DES/H2O). Compared to traditional water system, gelatin dissolved by DES/H2O can expose more active functional groups. Therefore, more ester bonds could be formed between gelatin and polyvinyl alcohol when using carbon diimide hydrochloride as a cross-linking agent. Results indicate that, when DES/H2O solvent contained 60% DES was used (based on the total mass of the DES/H2O solution), the prepared gelatin-based film precursor exhibited 95.23% of transmittance, 1 524.0 nm of particle size, and -31 ℃ of crystallization temperature. At a shear rate of 10 s-1, its viscosity was 449.07 mPa·s. These findings suggest that the prepared gelatin-based precursor solution demonstrates strong cross-linking effect, good compatibility, and stable internal structure, providing a novel method for processing gelatin-based films with favorable physicochemical properties.

2024 Vol.34(5): 32–39    [Abstract] ( )    [PDF 1821 KB ] ( )

Zeolite tanning agent and chrome tanning agent, respectively, were used to retan the wet white prepared by using the organic tanning agent KELINTAN EIT AT. The absorption characteristics of the retanned leather fibers to the anionic dyes Direct Blue 80 and Acid Red 249 were investigated by using the one-way variable method. Scanning electron microscope, physical adsorption tester - specific surface area analysis, and nanoparticle size surface potential analyzer were used to characterize the retanned leather fibers, including fiber looseness and isoelectric point. Results showed that the isoelectric point of KELINTAN EIT AT tanning fibers increased from 5.5 to about 7.0, and the specific surface area of the fibers increased and the degree of looseness increased under both the zeolite and chrome retanning systems. It is concluded that the chemical retanning mechanisms of zeolite and chrome tanning agents are the same in the wet dyeing and finishing process of KELINTAN EIT AT tanned leather. Furthermore, the ability of leather fibers to absorb and bind anionic dyes was improved, and chemisorption was the main absorption and binding mechanism. The absorption process was in accordance with the laws of the secondary kinetic model and the Langmuir isothermal model. The results of this study provide theoretical support for the development of wet dyeing and finishing processes for chrome-free tanning systems.

2024 Vol.34(5): 40–49    [Abstract] ( )    [PDF 2136 KB ] ( )

Adsorption operation plays a crucial role in the chemistry and chemical engineering. Developing environmentally friendly, cost-effective, and efficient adsorption materials is of great significance for the future development of adsorption technology. Collagen fibers (CFs), a kind of natural biomass resource mainly derived from animal skins, possess a unique three-dimensional hierarchical structure and abundant active functional groups, which suggesting their considerable research value and boundless potential for the production of superior adsorbents. This review provides an overview of the advancements in the development of CFs-based adsorbents, specifically focusing on CFs immobilized by tannin, CFs loaded with metal ions, and CFs grafted with functional groups. The application of these adsorbents in the removal of radionuclide ions, toxic heavy metal ions, inorganic anions, organic contaminants, as well as in the separation of natural products and the immobilization of cells are discussed. Additionally, potential areas for future research and development of CFs-based adsorbents are also prospected.

2024 Vol.34(5): 50–59    [Abstract] ( )    [PDF 1940 KB ] ( )

Polyurethane has excellent physical and mechanical properties, and is widely used in leather, functional materials and medical fields. However, polyurethane is prone to combustion, so the introduction of nanomaterials with flame-retardant function in polyurethane is of great significance to improve the fire safety of polyurethane materials. This review first summarized the advantages of nanomaterials over traditional flame retardants. The development of flame-retardant polyurethane nanocomposites in terms of preparation, mechanism, and applications in leather and functional materials was demonstrated in this review. We also discussed the introduction of various types of nanomaterials, e.g., carbon nanotubes, metal-organic frameworks, and MXene. Meanwhile, research and development direction of the flame-retardant polyurethane nanocomposites was discussed.

2024 Vol.34(5): 60–66    [Abstract] ( )    [PDF 1667 KB ] ( )

Due to the poor compatibility between ammonium polyphosphate (APP) flame retardant and anion polyurethane, the resulting polyurethane still produces a large number of droplets when burned. Phosphorus-based flame retardants were used to modify anion waterborne polyurethane for flame retardant enhancement. The optimal dosage of the two flame retardants, APP and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivatives (DOPO-PHB), and an economically efficient flame-retardant modification system were investigated. The flame retardancy and thermal degradation performance were examined through limiting oxygen index (LOI), vertical burning test, and thermogravimetric analysis. The mechanical properties of the resulting film were determined using a tensile testing machine. Results indicate that a LOI value of 27.8% and a V-0 rating in the vertical burning test were achieved when 1% APP and 4% DOPO-PHB were added. Without melting drops, the mechanical properties of polyurethane were improved, and its compatibility was enhanced.

2024 Vol.34(5): 67–73    [Abstract] ( )    [PDF 1996 KB ] ( )

A mathematical model with waterborne polyurethane (WPU) content, temperature during the curing process and the reduction degree of microfiber leather as variables was developed to predict the thermal and humidity comfort performance of microfiber suede leather by performing orthogonal experimentation, using both statistical regression and neural network methods. The model was subjected to normality testing and analysis of variance, and the influencing factors were analyzed and compared to assess the predictive ability of the model. The results showed that the WPU content had a significant effect on moisture permeability, and the degree of reduction had the greatest effect on breathability. The fitting coefficients of breathability and moisture permeability in the statistical regression prediction model were 0.871 and 0.865, respectively, while these coefficients in the neural network prediction model were 0.997 and 0.989, respectively. Overall, the neural network model performed better than the statistical regression model in predicting the thermal and wet comfort of microfiber suede leather.

2024 Vol.34(5): 74–80    [Abstract] ( )    [PDF 2411 KB ] ( )

In order to deeply explain and analyze the matching relationship between the shape design of sports shoes and cultural imagery, and to enhance the users' recognition of the cultural elements in the design of sports shoes, a method of designing sports shoes with cultural imagery was proposed by combining perceptual engineering and shape grammar. Through collecting, evaluating and selecting samples of sports shoes, and carrying out shape deconstruction and feature interpretation, the Minnan heritage culture was selected as the object of cultural imagery research, and the design elements were determined through factor analysis and cluster analysis. A factor library of Jin Cang embroidery patterns was constructed, and the shape grammar was applied to product design. Results show that users have clear subjective impressions of the cultural imagery, and the perceptual factors of the shoes are mainly focused on the two aspects of shape and style. This method successfully extracted the non-heritage cultural imagery elements that meet the users' perception and integrated them into the shoe design, which provides an empirical case and methodological reference for related product design.

2024 Vol.34(5): 81–85    [Abstract] ( )    [PDF 1130 KB ] ( )

The aim of this study was to investigate the test-retest reliability of spatiotemporal parameters and lower-limb joint angles, obtained from Xsens inertial-sensor-based motion capture system during walking in healthy subjects. Fifteen able-bodied adults completed two separate gait assessments, separated by 6±1?days. Spatiotemporal parameters and lower-limb joint angles were analyzed. The intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were used to compare the relative reliability and absolute reliability of those two sessions. The results showed that the ICC of the spatiotemporal parameters was generally fair-to-excellent, and most of the SEM was excellent. All joints in sagittal plane were excellent and fair-to-excellent agreement was found for all joint angles in transverse and frontal plane, and SEM results were excellent. Our results suggest that the Xsens system is reliable for measuring spatiotemporal gait parameters and lower-limb joint angles in healthy young people, and it can be used by clinicians or researchers to conduct gait research.

2024 Vol.34(5): 86–91    [Abstract] ( )    [PDF 1422 KB ] ( )

Pediatric foot diseases have a significant negative impact on children's growth and development. Therefore, intervening with orthopedic shoe insoles is essential for the affected children. Using a mobile APP to customize shoe insoles is a convenient and efficient solution. We firstly reviewed the existing studies and summarized the application progress of 3D printing technology in the field of pediatric orthopedic shoe insoles. Then, based on the 3D printing technology and service design concept, a 3D-printed custom pediatric orthopedic shoe insole APP was developed. This APP integrated many functions such as foot data collection, intelligent matching, and personalized customization, aiming to provide more precise and convenient orthopedic shoe insole customization service. Through this APP, users can obtain personalized and comfortable orthopedic shoe insoles, enhancing the effectiveness of rehabilitation treatment and user experience. The launch of this APP will provide a new solution for children's foot health, with significant clinical and market value.

2024 Vol.34(5): 92–98    [Abstract] ( )    [PDF 1671 KB ] ( )

The Kingfisher feather craftsmanship is an intangible cultural heritage with great Chinese cultural significance, which occupies an important position in ancient high-grade clothing. Because the feather materials used do not meet the demands of the times, it is on the verge of dilemma. Through the substitution test of several natural feather materials and textile materials, this article delved into the transformation of design and innovative application of the Kingfisher feather craftsmanship based on the distinctive features of modern leather accessories. On this basis, it is proposed that the design and application of the Kingfisher feather craftsmanship need to be driven by consumption demands, highlighting fashionable attributes while endowing the products with a sense of story through the integration of intangible cultural elements. With this study, it is expected to provide thoughts and reference for the productive protection of Kingfisher feather craftsmanship in the field of leather products.

2024 Vol.34(5): 99–106    [Abstract] ( )    [PDF 2118 KB ] ( )

The Dechang Lisu embroidery patterns are rich in themes and exquisite in shapes, and the patterns are inspired by daily life with distinctive regional characteristics and cultural connotations. Combining the research methods of design and ethnology, and based on the first-hand graphic and textual data collected from fieldwork and interviews with the inheritors, this research analyzed and summarized the embroidery materials and techniques, pattern themes and modeling techniques, pattern compositions and color combinations, etc., and extracted the typical patterns for design transformation. Adhering to the concept of green development, the products were made of recyclable and safe biodegradable plant fiber synthetic leather. By combining innovative derivative patterns with embroidery and dyeing techniques, versatile and fashionable luggage bags are created. This research aims to explore the artistic design value and diversified transformation path of ethnic embroidery patterns in plant leather bags, and provide a new reference for promoting the development of Dechang Lisu intangible cultural heritage and the innovative practice of ethnic handicrafts.

2024 Vol.34(5): 107–115    [Abstract] ( )    [PDF 3181 KB ] ( )

Cross modeling is an important aspect of Chinese traditional clothing culture. With the historical development and evolution, it radiates the new era style, becomes a major design feature of contemporary clothing, and has high research value. Based on the design theory, this paper traced the origin and "etiquette" culture of cross modeling in clothing, analyzed its design characteristics, built an innovative design application model of cross modeling in women's leather clothing on this basis, and exemplified the feasibility of this model in practice to create a "six-step" process of leather clothing design innovation. The research shows that cross modeling has the characteristics of various design forms, flexible design layout and multi-dimensional design methods, and the innovative design application model based on this can help women's leather clothing design. Cross modeling design can adapt to the personalized needs of 20-30 year old female audience for leather clothing. Leather clothing design innovation can follow a "six-step" process.

2024 Vol.34(5): 116–124    [Abstract] ( )    [PDF 2946 KB ] ( )

Leather, as an ancient material, has a history of application for tens of thousands of years. With the development of economy and society and the change of modern consumer demand, there are new requirements for the design and development of leather materials. Crossover design is the design means of the new era. The use of crossover design can make leather materials interact with each other in external aesthetic feeling and internal quality, and make the design of leather materials more innovative. The work Embroidery Red Flag, through crossover design method, digital technology, leather and intangible cultural heritage (referred to as "intangible") Shu embroidery technology cross-border integration, and applied to leather installation art. The experiment of process and process in the early stage of work design and development is helpful to the reasonable and orderly design of leather products. Through the design and production of leather products with Chinese characteristics and trend aesthetic characteristics, the cross-border cooperation between leather materials and traditional elements is realized, a new path of leather products innovation and development in the new era is explored, and new life vitality is injected into the modernization development of leather products.

2024 Vol.34(5): 125–132    [Abstract] ( )    [PDF 1207 KB ] ( )

As China enters a stage of high-quality development, industrial upgrading is accelerating, which has put forward higher requirements for the development of vocational education, especially for the construction of double-qualified teachers. Teacher enterprise practice is an important measure to promote the combination of theory and practice, and improve teachers' ability and quality. It is also an important basis for promoting the integration of industry and education, school-enterprise cooperation, and promoting teaching reform and classroom revolution. This topic is about the leather shoe industry through field visits, questionnaire survey and studying the leather shoe industry vocational education teacher in the enterprise practice, including planning, organization form, implementation plan, effect evaluation, evaluation method, existing problems, etc. By summarizing the concise analysis, we combed out the teachers’ position, responsibilities and collaborative mode in the enterprise practice during deepening the process of government, enterprise and industry. This article will offer the support for promoting the overall abilities of teachers and transformation and upgrading of leather shoe industry.