Leather Fibers Research Articles

The Effect of Temperature on the Sorption of Polymer from Latex on Leather Fibres

An examination is made of the effect of temperature on the sorption properties of leather fibres during their sizing with dispersions of polymer binders in the production of porous fibre composites of the shoe board type.

Preparation, properties, and characterization of novel fine leather fibers/polyvinyl alcohol composites

The water-based dispersion of fine leather fibers (FLF) was firstly prepared in our laboratory by high pressure homogenization. The solution casting method of water-based dispersion of FLF and polyvinyl alcohol (PVA) was used to fabricate the composite films. In this study, the influences of FLF content on the structures and properties of resulting composites were investigated systematically. Experimental results showed that there was an obvious small size effect of FLF in the composite films. Esterification and etherification reactions between FLF and PVA were confirmed by FTIR analysis; XRD and DSC analyses showed that FLF had the nucleation effect on PVA. The micrograph of SEM revealed that composite film with 40 wt% FLF content had compact internal structure and vague interface, and its value of tensile strength could reach maximum 51.8 MPa. Besides, TGA test showed that the thermal stability of composite films with FLF content beyond 30 wt% were much greater than that of PVA at temperature above 350°C. Moreover, composite films were deprived of hydrophilicity to a certain extent and the antibacterial rate of composite films with 40 wt% and 60 wt% FLF content were more than 90% totally. POLYM. COMPOS., 36:1186–1194, 2015. © 2014 Society of Plastics Engineers

Synthesis and application of sulfonated adipic dihydrazide formaldehyde-based resins under different molar ratios as effective leather re-tanning agents

Sulfonated adipic dihydrazide formaldehyde condensates were synthesized under different mole ratios of adipic dihydrazide, sodium metabisulfite and formaldehyde in three processing steps. Mole ratio of sodium metabisulfite to adipic dihydrazide (S/ADH) varied from 0.1 to 0.5 and formaldehyde to adipic dihydrazide mole ratio (F/ADH) varied from 1 to 3. Fluidity and gelling behavior of resin solutions were studied with varying degree of sulfonation and varying mole ratios of formaldehyde to adipic dihydrazide. Viscosity of resins increases with increasing formaldehyde to adipic dihydrazide mole ratio and decreases with increasing sodium metabisulfite to adipic dihydrazide mole ratio. Stable resins were comparatively applied as re-tanning agent on chrome tanned goat skins against commercial sulfonated urea formaldehyde resin. Tensile strength, tear strength, elongation-at-break percentage, grain cracking tests of the re-tanned leathers were comparatively performed. Morphological analysis of grain surface, cross section of leather fibers re-tanned by control and synthesized resins were analyzed by scanning electron microscope which showed more compactness of the grain and fiber structures of experimental re-tanned leather. Organoleptic properties of optimally re-tanned leather show better performance in comparison to control re-tanned leather treated with sulfonated urea formaldehyde resin. Free formaldehyde contents in the resin solutions were found less than 0.05 % and 10 ppm of free formaldehyde contents in re-tanned leather with synthesized resins. Dried resin with optimum re-tanning performance showed good thermal stability evaluated by thermal gravimetric analysis. Proton NMR and FTIR techniques were used for characterization of resin functionalities.

Alkaline Hydrolysis of Chromium Tanned Leather Scrap Fibers and Anaerobic Biodegradation of the Products

Chromium tanned leather wastes fibers are difficult to manage by chemical and biological processes due to the strong bonds established between collagen and chromium. Therefore, it is of great interest to develop treatments that disrupt recalcitrant bonds and may open new perspectives to materials valorization. A temperature and pressure-assisted alkaline hydrolysis method has been studied. The effects of sodium hydroxide concentration, temperature, holding time and leather fibers to solution ratio on organic matrix destruction, chromium dissolution and anaerobic biodegradability of hydrolyzates obtained are reported. The more suitable conditions found are leather fibers treatment at 423 K for 1.5 h with NaOH 4 mol/L solution and solid to liquid (S/L) ratio (w/w) of 0.15 or 0.2. Under these conditions, more than 98 % of the leather and 85 % of chromium were dissolved. The hydrolyzates may be used in the leather process and show anaerobic biodegradability mostly in the range of 20–30 %. This work establishes an alternative route of treatment that promotes fast destruction of chromium tanned leather scrap, and may avoid its landfilling, contributing to recover part of resources contained in leather waste.

Ultrasound-assisted Acid red dye removal using leather fibre wastes as matrix: ‘intra wastes interaction’ approach

It is desirable to make effective use of solid wastes, as well as waste liquors, of the dye house generated from leather processing. The present study deals with the adsorption of Acid red 26 (Xylidine ponceau) dye using leather fibre waste (buffing dust) as substrate matrix by the means of ultrasound, magnetic stirring and conventional heating. The research examined the effect of various process parameters: ultrasonic power, concentration of dye, temperature and time. The dye uptake data have been fitted with Freundlich and Langmuir isotherms, indicating a useful dye adsorption process. A mechanism for dye adsorption in leather fibres has also been proposed. This study shows that it is possible to remove dyes from dye house effluent streams using leather waste fibres of buffing dust by means of ultrasound. Two different toxic wastes produced by the same industry can be effectively contained. This ‘Intra wastes interaction’ approach could reduce the burden of discarding wastes of other materials in the leather industry.

An Approach to Utilize Crust Leather Scrapes, Dumped into the Land, for the Production of Environmental Friendly Leather Composite

Among all the natural fiber, leather fiber is one of the animal fibers which is bearing hydrophilic and hydrophobic functional group. Leather is tanned with different types of chemicals and scraped crust leather containing chemical are coming from the leather industry after preparing footwear and leather products. In this was varied from 100 ml to 40 ml and benzoyl peroxide was used as a radical initiator. Tensile strength (TS), Young modulus and elongation at break (Eb) were measured. Tensile strength found to increase from 9.80 Mpa to 10.85 MPa. Young’s modulus was found highest in 70:5 ratios and it was 158.16Mpa research an attempt was taken to prepare composite with waste scrape crust leather. Leather fiber reinforced polyester resin based composites were prepared by wet layup method. Polyester content in the composite.Scraped crust reinforced composite will reduce the environmental pollution. So it can be concluded that scraped crust leather reinforced composite found to have better result than matrix and reinforced material.

Chromed Leather Dyeing Peculiarities when Deliming with Peracetic Acid

The research was aimed to investigate the influence of deliming with peracetic acid on leather dyeing kinetics. Hydrophobic C.I. Acid Red 213 and hydrophilic C.I. Acid Red 423 dyes were used. Sorption of dye depends on hydrophobicity/hydrophility of dye and dyeing temperature. Equilibrium of process is reached faster using hydrophobic C.I. Acid Red 213 at 45 ºC. However, both control and experimental leather fibres adsorb more hydrophilic dye C.I. Acid Red 423 and this fact does not depend on temperature. The diffusion coefficient of dye C.I. Acid Red 423 calculated according to Weisz model is higher when dyeing conventional leather. The change of deliming method has influence on chromed leather dyeing but this influence is not significant. The adsorption ability of control leather fibres at 30 ºC and 45 ºC is higher using both dyes as compared to the dyeing the experimental one. The increase of dyeing temperature increases the adsorption ability independently on the sort of leather fibres. Such dependence of the adsorption ability on the temperature shows that hydrophobic action and van der Waals forces prevail between dye and fibres during dyeing process. The Gibbs energy changes show that adsorption of both dyes by leather fibres independently on their sort is a spontaneous process. The affinity of both dyes to conventional leather fibres is higher comparing with experimental one. The change of enthalpy is positive in all cases, and it means that the driving force of the dyeing is the change of entropy.DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4431

Preparation of Comb‐Like Amphiphilic Styrene Maleic Anhydride Copolymer Derivatives and Their Modification to Surface of Chrome‐Tanned Collagen Fiber

AbstractA series of comb‐like amphiphilic surfactants of sodium salts of fatty alcohol polyoxyvinethene monoester, i.e., SMA‐g‐O‐3, SMA‐g‐O‐6, SMA‐g‐O‐10, SMA‐g‐O‐15 and SMA‐g‐O‐20, were prepared through the esterification modification to styrene‐maleic anhydride copolymer (SMA) using fatty alcohol polyoxyethylene ether in dimethylformamide(DMF). The products of esterification modification were characterized by FTIR and GPC analysis, and the esterification reaction rate was calculated by measuring the acid values of SMA and its esterification product. Then, sodium salts of those esterification substances were applied to the leather retaining and fatliquoring process to study their effects on hydrophobicity of the treated leather fiber, such as static Water Contact Angle (WCA) on the leather surface and water absorption of the treated leather. Results showed that all the esterification rates were more than 90 %; moreover, both the WCA and water absorption of the processed chrome‐tanned collagen fibers were related to the number of oxyethyl groups in the fatty alcohol polyoxyethylene ether. WCA decreases and water absorption increases instead with augmentation of the oxyethyl group number.

Preparation and characterization of the covalent-integrated poly(lactic acid) and scrap leather fiber composites

Scrap leather fibers (SLFs) modified with active silane containing epoxide groups were incorporated into poly(lactic acid) (PLA) modified by vinyl trimethoxysilane, i.e., the PLA/SLF composites were prepared for bio-composites by solvent compounding technology in this article. The effects of silane coupling agents on the structures of PLA and SLF molecules were examined, and the mechanical properties and thermal stability of PLA/SLF composites were also measured. The results of Fourier-transform infrared spectroscopy (FTIR) had proved that silane had been incorporated successfully to PLA and SLF molecules by means of the solvent technology. Scanning electric microscopy (SEM) was used to investigate both the changes in shapes between the pristine SLFs and the treated SLFs and the microscopic structures of composites. According to SEM results, it was shown that there were some significant differences between the untreated and treated SLFs, and a double continuous phase structure had occurred in PLA/SLF composites due to the excellent dispersion of SLFs in matrix. The addition of the treated SLFs into PLA resulted in a distinct improvement of the impact and tensile strengths. When the mass fraction of the treated SLFs was 15%, the notched impact strength and tensile strength of PLA/SLF bio-composites were improved by 34.4% and 21.2% compared with the pristine PLA, respectively. Additionally, with the increase of the modified SLFs content, the thermal stability of PLA/SLF bi-composites was apparently improved. The macroscopic properties of bio-composites were found to be strongly dependent on their components, concentration, dispersion and resulted morphological structures.

The Footwear of Klaipėda Dwellers in the 16th and 17th Centuries

This report reviews leather footwear discovered during the latest archaeological research in Klaipėda, in investigations carried out at 3 Kurpių St in 2007 and 2008, and at 10 Žvejų St in 2006 (headed by R. Braciulienė). Another aim is to present examples of the footwear of Klaipėda dwellers in the 16th and 17th centuries which are of interest in terms of their shape and style, and which are typical of the shoes of the West European Renaissance and of the townsfolk of the Early Modern Period. The following types of footwear are presented: primitive shoes, low-cut shoes, mules and children’s shoes. The report describes the parts of the footwear, joining methods, seams and decorative components. It discusses differences between the footwear of the 16th and the 17th centuries, and refers to morphological studies and microchemical analyses of archaeological leather and thread fibre conducted by other experts. DOI: http://dx.doi.org/ 10.15181/ab.v16i0.42 Key words: archaeology, footwear, shoes, primitive shoe, low-cut shoe.

Synthesis of a phenol copolymer with horseradish peroxidase and the study of its structure–property relations

AbstractA phenol copolymer was synthesized by the free‐radical copolymerization of p‐hydroxybenzaldehyde (HBA) and p‐phenolsulfonate with horseradish peroxidase (HRP)/H2O2 as an initiator. The synthesis process included aldehyde protection via acetalization, enzymatic polymerization, and aldehyde deprotection via hydrolysis of acetals. The effects of the monomer ratio and the HRP and H2O2 composites on the properties of poly(p‐hydroxybenzaldehyde‐co‐p‐phenolsulfonate) [poly(HBA‐co‐PS)] were investigated by the determination of the shrink temperature (Ts) of tanned leather. The poly(HBA‐co‐PS) structure was characterized by Fourier transform infrared spectroscopy, NMR, UV spectroscopy, and gel permeation chromatography. The mechanism of enzymatic copolymerization, including initiation, H transfer, radical transfer, coupling, termination, differed from that of traditional free‐radical polymerization. A remarkable characteristic was that poly(HBA‐co‐PS) had a large conjugated structure in its molecules that markedly improved the activity of the aldehyde and hydroxyl groups and showed easy crosslinking in the leather fibers. The applied results showed that the Ts of tanned leather with poly(HBA‐co‐PS) reached 83.6°C. Poly(HBA‐co‐PS) could be used as agent for tanning leather. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013

Structure and Properties of Copolymer Tannage of Vanillin and Gallic Acid with HRP Initiation

A copolymer of vanillin and gallic acid was synthesized using HRP/H2O2 as initiator. The chemical structure of the copolymer was characterized by means of FTIR, NMR and GPC. The copolymer was applied in making leather as a tanning agent and the shrinkage temperature (Ts) of tanned leather reached 82.5°C. The average thickness increment ratio (E) of retanned leather was 19.4%. It has also excellent assisting dyeing and soft leather fibers properties. The application leather has desired dyeing effect and excellent softness.

The Physical Properties of Ultra-Short Leather Fiber Extracted from Chromed Leather Waste and its Use in Textile Industry

In order to probe the possibility of utilizing chromed leather wastes from the view of textile, firstly ultra-short leather fiber of 0.01～0.5cm was extracted by special equipment. Then the fiber structure was characterized; the moisture absorbency was tested and compared with wool and silk protein fibers. On the above basis, ultra-short collagen fiber suede fabric was developed successfully. The results indicate that ultra-short collagen fibers exist in bundles, adhesion forces between fibers are larger those of single (bundle) fiber strength. Their moisture absorbency is similar to that of wool. The micro-suede fabric made is suitable for decorating materials.

Synthesis and Properties of Phenolic Syntan with HRP Catalysis

A phenolic syntan GA-SHBS had been synthesized by radical copolymerization of gallic acid (GA) and sodium 4-hydroxybenzenesulfonate (SHBS) using horseradish peroxides (HRP)/H2O2 as catalyst. The effects of monomer ratio, reaction temperature and HRP dosage on syntan were discussed. The optimum performance of GA-SHBS was got when the molar ratio of GA: SHBS is 1:1 in the presence of 5 mg HRP at 35°C in pH 7.0. The chemical structure of copolymer was characterized by means of FTIR and NMR. The mechanism of polymerization between GA and SHBS and binding mechanism between syntans and leather fibers were proposed. The copolymer was used in making leather as tanning agent and retanning agent respectively, applied results showed that the Ts of tanned leather can reach to 75.6°C, re-tanned leather has the merits of good uniformity, fullness, softness, fine grain and non-plastic feel etc. Syntan also has good permeability, excellent tanning performance and dyeing effect.

Preparation and characterization of poly (vinyl butyral)‐leather fiber composites

AbstractThis study reports the preparation and characterization of composites with recycled poly (vinyl butyral) (PVB) and wet blue leather fiber with leather contents of 30, 50, and 70 wt%, using an extruder equipped with a Maillefer single screw operated with a flat extrusion die. The components of the composites were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and Fourier transform infrared spectroscopy (FTIR). After extrusion, the PVB/leather composite plates were compression‐molded to obtain specimens for testing the tensile properties, hardness, abrasion resistance, and tear strength. The morphologies of the composites were analyzed by scanning electron microscopy (SEM). The DMA and FTIR analyses showed that the recycled PVB contained plasticizer remained in the polymer matrix after extrusion. The SEM analysis revealed good interfacial adhesion between the PVB matrix and the leather fibers. Increasing the leather content in the composites led to a significant increase in the tensile modulus and a reduction in the tensile strain at breaks. The Shore hardness of the composites increased with the wt% of leather, whereas the abrasion resistance decreased. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers.

Highly Stable Nonionic Fatliquors Based on Ethoxylated Overused Vegetable Oils

AbstractOverused vegetable oils, which are considered to be a waste and available in huge quantities after frying processes, were directly ethoxylated using a conventional cheap catalyst in order to obtain an economically valuable ethoxylated product to replace the imported intermediate derivatives and at the same time the environment will be rid of one of its pollutants. Therefore, this work was devoted to exploring its application as a fatliquoring agent in the leather industry. Overused sunflower and olein oils were directly ethoxylated using ethylene oxide gas in the presence of 3% KOH catalyst at 180 °C for 20 h. The prepared products were applied as nonionic fatliquors. The fatliquoring process is the operation in which a fatty matter is introduced into the leather fibers. The results obtained showed that the prepared ethoxylated overused oils were effective fatliquors with high HLB values giving stable oil in water emulsion as well as high stability against acid, alkali and different metallic salts. The fatliquored leather had improved mechanical properties such as tensile strength and elongation at break. In addition, a significant enhancement of the texture of the treated leather by the two prepared fatliquors as indicated from the scanning electron microscope images was observed. Also the results indicated that ethoxylated overused sunflower oil gave better results than those of ethoxylated overused olein oil.

Study of the sorption activity of the surface of leather fibres

The studies demonstrated the possibility of regulating the sorption activity of leather fibres by special treatment with solutions of syntans to ensure controlled sizing toward heterocoagulation and obtaining materials with a given structure and properties.

Study of the mechanism of sizing of modified fibres with different polymer dispersions

The expediency of modifying the surface properties of leather fibres by hydrothermal treatment and retanning with syntans to improve their sizing with polymer dispersion in manufacture of leather board is examined.

The Effect of Leather Fibers on the Properties of Rubber-Leather Composites

Finished leather waste resulting from footwear production is mainly managed by landfilling, thus wasting the contained resources. Recycling by incorporating these wastes in new composites would be a more sustainable option. In this work, styrene butadiene rubber and acrylonitrile butadiene rubber based compounds were charged with ≤1 mm leather fibers in the range of 12.5-300 parts per hundred parts of rubber (phr). Rubber-leather composites were vulcanized by compression molding and characterized regarding possible footwear functional applications as soles and in-shoe parts. The results obtained indicate that up to 10-20 phr of leather incorporation composites with improved tear strength are obtained. Tension and elongation decrease, but within the acceptable range for application. The remaining physical properties studied in these composites are not significantly influenced, and consequently, they are adequate for soles application. Above the referred range of incorporation and till 100 phr the composites properties are compatible with in-shoe components application.

Supercritical carbon dioxide‐assisted loosening preparation of dry leather

AbstractThe physical modification of the dry leather using supercritical carbon dioxide (SC‐CO2) was studied in this article. A series of loosening processes of the leather fibers were carried out by changing the experimental conditions such as experimental pressure, experimental temperature, and time. The samples were characterized by scanning electronic microscopy (SEM), Brunauer–Emmett–Teller (BET) and X‐ray diffraction (XRD). SEM images show that samples were loosened by SC‐CO2 and the leather fibers in micron size arrange more orderly after treatment. The BET surface area of treated samples increase from 1.67 m2/g to 6.33 m2/g with the changing of conditions. The optimal treatment conditions were determined. Moreover, XRD patterns indicate that aggregation structure of collagen fibers in the sample was altered by SC‐CO2, and it can be found that the loosening of leather mostly happened in amorphous regions of collagen fibers. Besides, the percent breaking elongation of the samples was examined by means of a tensile analyzing test, and it indicates that the elongation at break of all the treated samples in SC‐CO2 can increase to 128.2% compared with 95.9% of the original ones. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009