Pub Date : 2023-12-01DOI: 10.34314/jalca.v118i12.8252
Deepak N, Inbasekar C, Nishad Fathima Nishter
Although tanning makes the collagen matrix resilient against microbial attack, the chemicals used in the finishing process are susceptible to microbes. Hence, it is imperative to develop a finishing process with inherent antimicrobial properties. Leathers with antimicrobial properties evoke a considerable array of interest in consumers. The present study aims to enhance the antimicrobial properties of the leather using copper nanoparticles in the finishing and retanning process. Copper nanoparticles have been synthesized by chemical reduction using copper sulphate pentahydrate as the precursor with dialdehyde starch and gallic acid. The prepared nanoparticles have been characterized using UV-Visible spectrometry, dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction techniques. The prepared nanoparticles have been used in both retanning and finishing processes. The experimental leather retanned using copper nanoparticles possess good mechanical strength properties and color index value compare to the control. Nanoparticles are effective against both gram negative and positive bacterial organisms. The nanoparticles also inhibit the growth of common fungus, which can colonize on leather. Thus, the current study paves the way for a novel solution that is an alternative to biocides and antimicrobial chemicals and is more effective in inhibiting microbial growth.
{"title":"Bactericidal and Fungicidal Action of Copper Nanoparticles on Leather Surface","authors":"Deepak N, Inbasekar C, Nishad Fathima Nishter","doi":"10.34314/jalca.v118i12.8252","DOIUrl":"https://doi.org/10.34314/jalca.v118i12.8252","url":null,"abstract":"Although tanning makes the collagen matrix resilient against microbial attack, the chemicals used in the finishing process are susceptible to microbes. Hence, it is imperative to develop a finishing process with inherent antimicrobial properties. Leathers with antimicrobial properties evoke a considerable array of interest in consumers. The present study aims to enhance the antimicrobial properties of the leather using copper nanoparticles in the finishing and retanning process. Copper nanoparticles have been synthesized by chemical reduction using copper sulphate pentahydrate as the precursor with dialdehyde starch and gallic acid. The prepared nanoparticles have been characterized using UV-Visible spectrometry, dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction techniques. The prepared nanoparticles have been used in both retanning and finishing processes. The experimental leather retanned using copper nanoparticles possess good mechanical strength properties and color index value compare to the control. Nanoparticles are effective against both gram negative and positive bacterial organisms. The nanoparticles also inhibit the growth of common fungus, which can colonize on leather. Thus, the current study paves the way for a novel solution that is an alternative to biocides and antimicrobial chemicals and is more effective in inhibiting microbial growth.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"161 3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138621426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.34314/jalca.v118i12.8259
The Editors
After almost 24 years we had to say farewell to our beloved Executive Secretary, Carol Adcock
在将近24年之后，我们不得不向我们敬爱的执行秘书卡罗尔·阿德科克说再见
{"title":"A Bittersweet Occasion","authors":"The Editors","doi":"10.34314/jalca.v118i12.8259","DOIUrl":"https://doi.org/10.34314/jalca.v118i12.8259","url":null,"abstract":"After almost 24 years we had to say farewell to our beloved Executive Secretary, Carol Adcock","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"136 3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138622196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.34314/jalca.v118i11.8240
F. E. Ahmed, Aschalew Shitu, Zerihun Teshome, Endalamaw Yihune, Misganaw Bitew, H. Fenta
Ethiopia has one of the world’s largest livestock resources. However, the effects of disease, inadequate nutrition and management constrain the potential of this resource. Ectoparasites are one of the primary contributing factors in the tanneries for sheep and goat skin rejection. The aim of this study is to assess the impact of medicinal herbal plant extracts on ectoparasites (ticks) on small ruminants in Ethiopia. According to scientific and ethnomedical data gathered from respondents (farmers), the plant species P. dodecandra, E. globulus, C. macrostachyus, J. schimperiana, and C. aurea were used (by farmers) for the study. Phytochemical screening of extracts revealed the presence of flavonoids, alkaloids, phenols and saponins, tannins. Ticks from small ruminants (i.e goat and sheep) were collected and an in vitro adult tick immersion test was carried out using concentrations of 6.25, 12.5, 25, 50, and 100 mg/ml of all medicinal plant extracts. The temporal tick mortality was observed within 24-hours. In order to compare the results, distilled water and 12.5% amitraz was used as positive and negative controls, respectively. After 24 hours of exposure, P. dodecandra, J. schimperiana, and C. macrostachyus extracts had a moderate (60%) effect on tick mortality; however, C. aurea extract at 100 mg/ml and E. globulus extract at 50 mg/ml and 100 mg/ml had the highest mortality rate (80%). The study found that following in vitro treatment for the studied plants, the mean tick mortality increased considerably with increasing concentration and exposure duration. The existence of phytochemicals (active ingredients) in several plants, such as phenols, flavonoids, alkaloids, tannin, saponin, etc., may be the cause of their anti-ectoparasite effects. The study’s findings suggested that these plants might be crucial in reducing the need for chemical based medicines as well as managing the population of resistant ticks in an environmentally friendly manner.
埃塞俄比亚拥有世界上最大的牲畜资源之一。然而，疾病、营养不足和管理不善限制了这一资源的潜力。体外寄生虫是导致绵羊和山羊皮制革厂拒收的主要因素之一。本研究旨在评估药用植物提取物对埃塞俄比亚小型反刍动物体外寄生虫（蜱虫）的影响。根据从受访者（农民）处收集到的科学和民族医学数据，本研究（农民）使用了 P. dodecandra、E. globulus、C. macrostachyus、J. schimperiana 和 C. aurea 等植物物种。对提取物进行的植物化学筛选显示，其中含有黄酮类、生物碱、酚类、皂苷和单宁酸。收集小反刍动物（即山羊和绵羊）身上的蜱虫，使用浓度为 6.25、12.5、25、50 和 100 毫克/毫升的所有药用植物提取物进行体外成蜱浸泡试验。在 24 小时内观察到暂时性蜱死亡。为了比较结果，分别使用蒸馏水和 12.5% 的双甲脒作为阳性对照和阴性对照。接触 24 小时后，P. dodecandra、J. schimperiana 和 C. macrostachyus 提取物对蜱虫死亡率的影响适中（60%）；但 C. aurea 提取物（100 毫克/毫升）和 E. globulus 提取物（50 毫克/毫升和 100 毫克/毫升）的死亡率最高（80%）。研究发现，在对所研究的植物进行体外处理后，随着浓度和暴露时间的增加，蜱的平均死亡率大幅上升。几种植物中存在的植物化学物质（活性成分），如酚类、黄酮类、生物碱、单宁、皂苷等，可能是它们具有抗外来寄生虫作用的原因。研究结果表明，这些植物对于减少对化学药物的需求以及以环保的方式管理抗药性蜱虫的数量至关重要。
{"title":"Anti-Ectoparasite Activity of Medicinal Herbal Plant in Terms of Reducing Ectoparasites Effect on Sheep and Goat Skins","authors":"F. E. Ahmed, Aschalew Shitu, Zerihun Teshome, Endalamaw Yihune, Misganaw Bitew, H. Fenta","doi":"10.34314/jalca.v118i11.8240","DOIUrl":"https://doi.org/10.34314/jalca.v118i11.8240","url":null,"abstract":"Ethiopia has one of the world’s largest livestock resources. However, the effects of disease, inadequate nutrition and management constrain the potential of this resource. Ectoparasites are one of the primary contributing factors in the tanneries for sheep and goat skin rejection. The aim of this study is to assess the impact of medicinal herbal plant extracts on ectoparasites (ticks) on small ruminants in Ethiopia. According to scientific and ethnomedical data gathered from respondents (farmers), the plant species P. dodecandra, E. globulus, C. macrostachyus, J. schimperiana, and C. aurea were used (by farmers) for the study. Phytochemical screening of extracts revealed the presence of flavonoids, alkaloids, phenols and saponins, tannins. Ticks from small ruminants (i.e goat and sheep) were collected and an in vitro adult tick immersion test was carried out using concentrations of 6.25, 12.5, 25, 50, and 100 mg/ml of all medicinal plant extracts. The temporal tick mortality was observed within 24-hours. In order to compare the results, distilled water and 12.5% amitraz was used as positive and negative controls, respectively. After 24 hours of exposure, P. dodecandra, J. schimperiana, and C. macrostachyus extracts had a moderate (60%) effect on tick mortality; however, C. aurea extract at 100 mg/ml and E. globulus extract at 50 mg/ml and 100 mg/ml had the highest mortality rate (80%). The study found that following in vitro treatment for the studied plants, the mean tick mortality increased considerably with increasing concentration and exposure duration. The existence of phytochemicals (active ingredients) in several plants, such as phenols, flavonoids, alkaloids, tannin, saponin, etc., may be the cause of their anti-ectoparasite effects. The study’s findings suggested that these plants might be crucial in reducing the need for chemical based medicines as well as managing the population of resistant ticks in an environmentally friendly manner.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139303893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.34314/jalca.v118i11.8242
Yirui Lin, Zhoucheng Jiang, Ya-nan Wang, Yunhang Zeng, Guo Xie, Bi Shi
Mass transfer of chemicals greatly affects leather production efficiency and product quality. Leather shows different motions in a rotating drum during processing, which is strongly associated with chemicals’ mass transfer. However, how leather motions affect mass transfer remains unclear, which disfavors highly efficient leather manufacturing process. Here, different leather motion states were obtained by adjusting the drum rotation speed. Experimental results showed that the duration of leather rolling motion greatly increased by 41% when the rotation speed increased from 5 r/min to 20 r/min, and the uptake of the tanning agent was consequently improved, which indicated that the rolling motion is beneficial to mass transfer. Computational fluid dynamics simulation results showed that the mass transfer rate under rolling motion was higher than those under slipping, elevating and hanging motions, because the flow velocity and concentration gradient near the leather surface were higher under rolling motion. Accordingly, increasing the rolling motion enhanced the mass transfer in leather processing. This work identifies the leather motion beneficial for mass transfer and provides guidance on operating condition optimization and drum design for high-efficiency leather production.
{"title":"Experimental and Computational Fluid Dynamics Investigation on Tanning Process in a Rotating Drum","authors":"Yirui Lin, Zhoucheng Jiang, Ya-nan Wang, Yunhang Zeng, Guo Xie, Bi Shi","doi":"10.34314/jalca.v118i11.8242","DOIUrl":"https://doi.org/10.34314/jalca.v118i11.8242","url":null,"abstract":"Mass transfer of chemicals greatly affects leather production efficiency and product quality. Leather shows different motions in a rotating drum during processing, which is strongly associated with chemicals’ mass transfer. However, how leather motions affect mass transfer remains unclear, which disfavors highly efficient leather manufacturing process. Here, different leather motion states were obtained by adjusting the drum rotation speed. Experimental results showed that the duration of leather rolling motion greatly increased by 41% when the rotation speed increased from 5 r/min to 20 r/min, and the uptake of the tanning agent was consequently improved, which indicated that the rolling motion is beneficial to mass transfer. Computational fluid dynamics simulation results showed that the mass transfer rate under rolling motion was higher than those under slipping, elevating and hanging motions, because the flow velocity and concentration gradient near the leather surface were higher under rolling motion. Accordingly, increasing the rolling motion enhanced the mass transfer in leather processing. This work identifies the leather motion beneficial for mass transfer and provides guidance on operating condition optimization and drum design for high-efficiency leather production.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"162 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139301414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.34314/jalca.v118i11.8239
Xiu He, Jinwei Zhang
For preparing a new kind of leather with transmittance and softness at the same time, glycerol was used to treat delimed and bleached split pelt. The softness, transmittance and mechanical properties were tested to evaluate the performance of soft and transparent leather (STL). FT-IR, SEM, XRD, DSC and TG were used to character the structure of STL and reveal the basic principle of STL manufacturing. The results showed that 25% glycerol based on limed pelt weight could make leather soft and transparent simultaneously. Pig pelt was more suitable for thin and transparent leather while cattle split was better for uniform and clear leather. Glycerol combined with collagen through multipoint hydrogen bonds, and the combination had slight positive effect on improving STL thermal stability. Fiber bundles of STL trended to disperse and collagen hierarchical structure including triple helix remained during transparent treatment. The soft and transparent leather could be a new choice for leather goods designers and might be a selectable substrate for high-performance electronic skin.
{"title":"A Method and Principle of Soft and Transparent Leather Manufacturing","authors":"Xiu He, Jinwei Zhang","doi":"10.34314/jalca.v118i11.8239","DOIUrl":"https://doi.org/10.34314/jalca.v118i11.8239","url":null,"abstract":"For preparing a new kind of leather with transmittance and softness at the same time, glycerol was used to treat delimed and bleached split pelt. The softness, transmittance and mechanical properties were tested to evaluate the performance of soft and transparent leather (STL). FT-IR, SEM, XRD, DSC and TG were used to character the structure of STL and reveal the basic principle of STL manufacturing. The results showed that 25% glycerol based on limed pelt weight could make leather soft and transparent simultaneously. Pig pelt was more suitable for thin and transparent leather while cattle split was better for uniform and clear leather. Glycerol combined with collagen through multipoint hydrogen bonds, and the combination had slight positive effect on improving STL thermal stability. Fiber bundles of STL trended to disperse and collagen hierarchical structure including triple helix remained during transparent treatment. The soft and transparent leather could be a new choice for leather goods designers and might be a selectable substrate for high-performance electronic skin.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"57 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139302169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The enzymatic delimed pelts bating process using proteases is critical to improving the overall performance of the leather. Bating effectiveness is determined not only by the properties but also by the permeation behavior of the proteases. Imperfect methods to control protease permeation often results in uneven distribution of enzyme proteins in the pelts, leading to excessive enzymolysis of the surface layer and inadequate opening-up of the inner layer. In this study, the relative size of proteases and delimed pelts were analyzed, the permeation behavior of fluorescein-labeled proteases in the pelt was observed using a confocal laser scanning microscope (CLSM), and the effect of electrostatic interaction between protease and collagen proteins on the permeation of protease into the pelt was investigated. The results showed that, after dehairing, liming and deliming operations, the enzyme can easily permeate into the pelts due to the formation of large cavities and interfibrillar gaps. The permeation of protease within the delimed pelt is significantly influenced by the affinity (electrostatic interactions) between the collagen and protease proteins. The isoelectric point (pI) of the protease protein, the collagen and the pH of the solution directly influence the electrostatic properties and interactions. When the enzyme and collagen are similarly charged (electrostatic repulsion), the enzyme can easily permeate into the pelts; when the enzyme and collagen are oppositely charged (electrostatic attraction), the permeation of the enzyme into the inner layer is difficult, resulting in the accumulation of protease on the grain and excessive hydrolysis of the grain layer. Therefore, the established permeation regulation mechanism of protease based on electrostatic interactions between enzyme and collagen could serve as an important basis for the selection of protease and the regulation of the enzymatic bating process.
{"title":"Effect of Electrostatic Interaction between Collagen and Enzymes on Permeation of Protease into the Pelt during Leather Bating Process","authors":"Yiwen Zhu, Jinzhi Song, Xu Zhang, Mengchu Gao, B. Peng, Chunxiao Zhang","doi":"10.34314/jalca.v118i10.8231","DOIUrl":"https://doi.org/10.34314/jalca.v118i10.8231","url":null,"abstract":"The enzymatic delimed pelts bating process using proteases is critical to improving the overall performance of the leather. Bating effectiveness is determined not only by the properties but also by the permeation behavior of the proteases. Imperfect methods to control protease permeation often results in uneven distribution of enzyme proteins in the pelts, leading to excessive enzymolysis of the surface layer and inadequate opening-up of the inner layer. In this study, the relative size of proteases and delimed pelts were analyzed, the permeation behavior of fluorescein-labeled proteases in the pelt was observed using a confocal laser scanning microscope (CLSM), and the effect of electrostatic interaction between protease and collagen proteins on the permeation of protease into the pelt was investigated. The results showed that, after dehairing, liming and deliming operations, the enzyme can easily permeate into the pelts due to the formation of large cavities and interfibrillar gaps. The permeation of protease within the delimed pelt is significantly influenced by the affinity (electrostatic interactions) between the collagen and protease proteins. The isoelectric point (pI) of the protease protein, the collagen and the pH of the solution directly influence the electrostatic properties and interactions. When the enzyme and collagen are similarly charged (electrostatic repulsion), the enzyme can easily permeate into the pelts; when the enzyme and collagen are oppositely charged (electrostatic attraction), the permeation of the enzyme into the inner layer is difficult, resulting in the accumulation of protease on the grain and excessive hydrolysis of the grain layer. Therefore, the established permeation regulation mechanism of protease based on electrostatic interactions between enzyme and collagen could serve as an important basis for the selection of protease and the regulation of the enzymatic bating process.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"4 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139324084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-02DOI: 10.34314/jalca.v118i10.8230
Min Jiang, Yuanhang Xiao, Jun Sang, Chunhua Wang, Jiajing Zhou, Wei Lin
Developing alternative tanning agents to avoid the potential environmental and human health risks from the conventional chrome tanning is essential for the leather industry. In this work, we prepared an eco-friendly biomass-based tanning agent dichlorotriazinyl chitooligosaccharide (DTCS) by modifying chitooligosaccharide (COS) with cyanuric chloride (CC) for chrome-free leather manufacture. The synthesis of such biomass-based tanning agent was systematically optimized to obtain the target product with high grafting degree of 67% and weight-average molecular weight (Mw) of 1465 g/mol. The non-pickling tanning procedure using DTCS was investigated, and the interactions between DTCS and collagen fibers were studied. Our results showed that the hydrothermal stability of the tanned leather was significantly increased, i.e., the shrinkage temperature (Ts) exceeding 82.0°C, and the mechanical properties were improved. Moreover, the organoleptic properties of leather (e.g., fullness, softness and grain tightness) exhibited obvious improvement. This research not only offers a reliable approach for cleaner leather manufacturing while addressing the underlying ecological pressure, but also highlights the emerging use of biomass materials in the leather industry.
{"title":"Biomass-based Tanning Agent for Sustainable Leather Manufacture via Cyanuric Chloride Modified Chitooligosaccharide","authors":"Min Jiang, Yuanhang Xiao, Jun Sang, Chunhua Wang, Jiajing Zhou, Wei Lin","doi":"10.34314/jalca.v118i10.8230","DOIUrl":"https://doi.org/10.34314/jalca.v118i10.8230","url":null,"abstract":"Developing alternative tanning agents to avoid the potential environmental and human health risks from the conventional chrome tanning is essential for the leather industry. In this work, we prepared an eco-friendly biomass-based tanning agent dichlorotriazinyl chitooligosaccharide (DTCS) by modifying chitooligosaccharide (COS) with cyanuric chloride (CC) for chrome-free leather manufacture. The synthesis of such biomass-based tanning agent was systematically optimized to obtain the target product with high grafting degree of 67% and weight-average molecular weight (Mw) of 1465 g/mol. The non-pickling tanning procedure using DTCS was investigated, and the interactions between DTCS and collagen fibers were studied. Our results showed that the hydrothermal stability of the tanned leather was significantly increased, i.e., the shrinkage temperature (Ts) exceeding 82.0°C, and the mechanical properties were improved. Moreover, the organoleptic properties of leather (e.g., fullness, softness and grain tightness) exhibited obvious improvement. This research not only offers a reliable approach for cleaner leather manufacturing while addressing the underlying ecological pressure, but also highlights the emerging use of biomass materials in the leather industry.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"197 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139324702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-02DOI: 10.34314/jalca.v118i10.8229
Ze Liang, Zetian Zhang, Yang Liu, Zhengjun Li
Silicic acid-based tanning system is an effective and promising chrome-free tanning technology, and it is urgent to develop compatible post-tanning processes. Fatliquoring is one of the key procedures to determine the quality of resulted leather and fatliquoring agents mainly play the role of an effective softer/ plasticizer in leather production. However, there is a mismatch between most commercial fatliquoring agents (mainly compatible with chrome tanned leather) and silicic acid tanned leather (named SATL). Herein, an amphoteric polymer emulsion (APE) was prepared by free radical polymerization using methacryloxyethyl trimethyl ammonium chloride (DMC), 2-acrylamido-2-methylpropanesulfonate (AMPS), lauryl methacrylate (LMA), dimethylaminoethyl methacrylate (DMAEMA) as monomers. And in order to improve the lubricating property, APE was further compounded with castor oil to obtain an amphoteric fatliquoring agent (named COAPE). Comprehensive characterization showed that the amphoteric (pI=8.22) and amphiphilic APE could reduce the surface tension of water to 38.6 mN/m. The fatliquoring process was controlled by ingenious regulation of pH based on isoelectric points (pIs) of APE and SATL. In the initial stage, the pH of the bath was adjusted to be lower than the pIs of APE and SATL, amphoteric polymer molecules could easily penetrate into SATL leather as they are all positively charged. While during the fixing stage, the pH of the bath was adjusted between the pIs of APE and SATL, so the electrostatic interaction between amphoteric polymer molecules and SATL leather, as well as the aggregation of amphoteric polymers can promote their combination synergistically. As a fatliquoring agent, the application of COAPE demonstrated that its absorpotion rate (90.5%) was much higher than anionic commercial fatliquoring agent (63.2%), thus imparting SATL leather better softness (6.5 mm), elongation at break (95.5%) and tensile strength (11.6 N/mm2). These findings therefore provided scientific basis and technical support for the application of amphoteric materials to silicic acid-modified collagen matrix and would promote the practical application of silicic acid-based chrome-free tanning technology
硅酸基鞣制体系是一种有效且前景广阔的无铬鞣制技术，因此开发兼容的鞣后工艺迫在眉睫。加脂是决定成品革质量的关键工序之一，加脂剂在皮革生产中主要起着有效的软化剂/增塑剂的作用。然而，大多数商用加脂剂（主要与铬鞣革兼容）与硅酸鞣革（名为 SATL）之间存在不匹配。本文以甲基丙烯酰氧乙基三甲基氯化铵（DMC）、2-丙烯酰胺基-2-甲基丙磺酸盐（AMPS）、甲基丙烯酸月桂酯（LMA）和甲基丙烯酸二甲胺基乙酯（DMAEMA）为单体，通过自由基聚合制备了两性聚合物乳液（APE）。为了改善润滑性能，APE 进一步与蓖麻油复合，得到了两性加脂剂（命名为 COAPE）。综合表征结果表明，两性（pI=8.22）和两亲性 APE 可将水的表面张力降至 38.6 mN/m。根据 APE 和 SATL 的等电点（pIs），通过巧妙调节 pH 值来控制加脂过程。在初始阶段，浴液的 pH 值被调节到低于 APE 和 SATL 的等电点，两性聚合物分子很容易渗透到 SATL 皮革中，因为它们都带正电。而在固色阶段，浴液的 pH 值调节在 APE 和 SATL 的 pI 之间，两性聚合物分子和 SATL 皮革之间的静电作用以及两性聚合物的聚集可促进它们协同结合。作为加脂剂，COAPE 的吸收率（90.5%）远高于阴离子商业加脂剂（63.2%），从而赋予 SATL 皮革更好的柔软度（6.5 毫米）、断裂伸长率（95.5%）和拉伸强度（11.6 牛/平方毫米）。因此，这些研究结果为两性材料在硅酸改性胶原基质中的应用提供了科学依据和技术支持，并将促进基于硅酸的无铬鞣制技术的实际应用。
{"title":"Interaction between Amphoteric Polymer and Silicic Acid Tanned Leather","authors":"Ze Liang, Zetian Zhang, Yang Liu, Zhengjun Li","doi":"10.34314/jalca.v118i10.8229","DOIUrl":"https://doi.org/10.34314/jalca.v118i10.8229","url":null,"abstract":"Silicic acid-based tanning system is an effective and promising chrome-free tanning technology, and it is urgent to develop compatible post-tanning processes. Fatliquoring is one of the key procedures to determine the quality of resulted leather and fatliquoring agents mainly play the role of an effective softer/ plasticizer in leather production. However, there is a mismatch between most commercial fatliquoring agents (mainly compatible with chrome tanned leather) and silicic acid tanned leather (named SATL). Herein, an amphoteric polymer emulsion (APE) was prepared by free radical polymerization using methacryloxyethyl trimethyl ammonium chloride (DMC), 2-acrylamido-2-methylpropanesulfonate (AMPS), lauryl methacrylate (LMA), dimethylaminoethyl methacrylate (DMAEMA) as monomers. And in order to improve the lubricating property, APE was further compounded with castor oil to obtain an amphoteric fatliquoring agent (named COAPE). Comprehensive characterization showed that the amphoteric (pI=8.22) and amphiphilic APE could reduce the surface tension of water to 38.6 mN/m. The fatliquoring process was controlled by ingenious regulation of pH based on isoelectric points (pIs) of APE and SATL. In the initial stage, the pH of the bath was adjusted to be lower than the pIs of APE and SATL, amphoteric polymer molecules could easily penetrate into SATL leather as they are all positively charged. While during the fixing stage, the pH of the bath was adjusted between the pIs of APE and SATL, so the electrostatic interaction between amphoteric polymer molecules and SATL leather, as well as the aggregation of amphoteric polymers can promote their combination synergistically. As a fatliquoring agent, the application of COAPE demonstrated that its absorpotion rate (90.5%) was much higher than anionic commercial fatliquoring agent (63.2%), thus imparting SATL leather better softness (6.5 mm), elongation at break (95.5%) and tensile strength (11.6 N/mm2). These findings therefore provided scientific basis and technical support for the application of amphoteric materials to silicic acid-modified collagen matrix and would promote the practical application of silicic acid-based chrome-free tanning technology","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"7 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139324309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-01DOI: 10.34314/jalca.v118i9.8189
Min Zhu, Yudan Yi, Jia Fu, Yunhang Zeng, Ya-nan Wang
Dialdehyde polysaccharides possess a sustainable nature and good tanning performance. However, the lack of specific detectable groups in their molecular structure results in the difficulty in the determination of the location of dialdehyde polysaccharides in leather fiber networks. In this study, dialdehyde sodium alginate (DSA) tanning agent was fluorescent labeled by 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF). The purified DTAF–DSA showed high and stable fluorescent intensity at emission wavelength of 515.2 nm when the pH was over 6.0, and the temperature was in the range of 20°C to 50°C. DTAF–DSA was used in tanning and tracked using fluorescence microscopy. Its penetration in the fiber network could be clearly visualized, and its distribution in leather differed with the molecular weight of DSA. As a result, this fluorescence tracing technique could display the mass transfer behavior of dialdehyde polysaccharide tanning agents in leather matrix, which will provide underlying data for tanning mechanism exploration.
{"title":"Fluorescent Tracing of Dialdehyde Sodium Alginate Tanning Agent in Leather Matrix","authors":"Min Zhu, Yudan Yi, Jia Fu, Yunhang Zeng, Ya-nan Wang","doi":"10.34314/jalca.v118i9.8189","DOIUrl":"https://doi.org/10.34314/jalca.v118i9.8189","url":null,"abstract":"Dialdehyde polysaccharides possess a sustainable nature and good tanning performance. However, the lack of specific detectable groups in their molecular structure results in the difficulty in the determination of the location of dialdehyde polysaccharides in leather fiber networks. In this study, dialdehyde sodium alginate (DSA) tanning agent was fluorescent labeled by 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF). The purified DTAF–DSA showed high and stable fluorescent intensity at emission wavelength of 515.2 nm when the pH was over 6.0, and the temperature was in the range of 20°C to 50°C. DTAF–DSA was used in tanning and tracked using fluorescence microscopy. Its penetration in the fiber network could be clearly visualized, and its distribution in leather differed with the molecular weight of DSA. As a result, this fluorescence tracing technique could display the mass transfer behavior of dialdehyde polysaccharide tanning agents in leather matrix, which will provide underlying data for tanning mechanism exploration.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"23 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139346390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-01DOI: 10.34314/jalca.v118i9.8190
Ting Liu, Chunxiao Zhang, Xu Zhang, B. Peng, Mengchu Gao
With the development of enzymatic unhairing technology in the leather industry, enhancing the recycling of bovine hair is a new issue emerging in leather-making. In this work, the effects of alkali concentration, time, and temperature in the pretreatment, as well as enzyme dosage, time, temperature, and pH in the following treatment on the dissolution performance and keratin yield of bovine hair were investigated. Hence, the extraction process of keratin from bovine hair by the alkali-enzyme method was optimized. The results sho that the optimal conditions for the keratin extraction are as follows: for the pretreatment with alkali, the alkali concentration is 0.4 M, the pretreatment time is 1.0 h, the pretreatment temperature is 65°C, and for the following enzymatic treatment, the enzyme dosage is 3324 U/g bovine hair, the action time is 4.0 h, action temperature is 45°C, and the pH is controlled between 8.5-11.5. Compared with the alkali method, the alkali-enzyme method increases the keratin yield from 24.4% to 58.1%, and the alkali dosage is reduced by 50%. The prepared keratin had high in vitro antioxidant activity, which provided a new idea for the resource utilization of bovine hair waste.
{"title":"Resource Utilization of Bovine Hair Recycling from Enzymatic Unhairing during Leather Manufacturing","authors":"Ting Liu, Chunxiao Zhang, Xu Zhang, B. Peng, Mengchu Gao","doi":"10.34314/jalca.v118i9.8190","DOIUrl":"https://doi.org/10.34314/jalca.v118i9.8190","url":null,"abstract":"With the development of enzymatic unhairing technology in the leather industry, enhancing the recycling of bovine hair is a new issue emerging in leather-making. In this work, the effects of alkali concentration, time, and temperature in the pretreatment, as well as enzyme dosage, time, temperature, and pH in the following treatment on the dissolution performance and keratin yield of bovine hair were investigated. Hence, the extraction process of keratin from bovine hair by the alkali-enzyme method was optimized. The results sho that the optimal conditions for the keratin extraction are as follows: for the pretreatment with alkali, the alkali concentration is 0.4 M, the pretreatment time is 1.0 h, the pretreatment temperature is 65°C, and for the following enzymatic treatment, the enzyme dosage is 3324 U/g bovine hair, the action time is 4.0 h, action temperature is 45°C, and the pH is controlled between 8.5-11.5. Compared with the alkali method, the alkali-enzyme method increases the keratin yield from 24.4% to 58.1%, and the alkali dosage is reduced by 50%. The prepared keratin had high in vitro antioxidant activity, which provided a new idea for the resource utilization of bovine hair waste.","PeriodicalId":17201,"journal":{"name":"Journal of The American Leather Chemists Association","volume":"23 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139346876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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