甲基丙烯酸羟乙酯接枝改性淀粉的制备及性能

甲基丙烯酸羟乙酯(HEMA)与降解淀粉(ST)在过硫酸铵(APS)引发下,通过接枝共聚反应,制备了接枝改性淀粉,讨论了APS、HEMA、反应温度和反应时间对接枝效率(GE)和接枝率(GP)的影响。结果表明,在w(ST)=16.4%的水溶液中,当w(HEMA)=5.08%,w(APS)=0.84%时,于50℃反应280 min后,所得接枝改性淀粉的GE和GP分别为40%和27.5%。红外光谱(FTIR)和凝胶渗透色谱(GPC)确证了产物结构。复鞣革应用结果表明,接枝改性淀粉复鞣革的增厚率、丰满度、柔软性、弹性、发泡感等有所提升。接枝改性淀粉复鞣革的力学性能与参考样相当,产物具有复鞣性能。     

Graft polymerization of methyl methacrylate onto short leather fibers

Summary In this work, the graft polymerization of methyl methacrylate (MMA) monomer onto short leather fibers (SLF) was investigated as a function of the monomer/leather fiber ratio. This chemical modification was made by aqueous emulsion polymerization initiated by a redox system. The effect of' the monomer concentration on the grafting parameters (deposited and grafted polymer, as well as grafting efficiency) were determined. Composites formulated with SLF without chemical modification have showed lower tensile and impact properties in comparison with composites formulated with treated fibers. However, the elongation at break values for both systems remained similar as the MMA content changed. The morphology of SLF grafted with MMA was examined by both optical light microscopy (OLM) and scanning electron microscopy (SEM). Micrographs have shown polymer deposition on individual fibers and bundles of SLF. They have also revealed that PMMA may interpenetrate the SLF network and be deposited in large and coarse aggregates around individual fibers, but without occupation of the free space in the fiber net. Received: 1 October 1998/Revised version: 25 January 1999/Accepted: 25 January 1999     

阳离子角蛋白絮凝回收利用废水中的皮革助剂

通过在角蛋白分子上引入季铵基制得一种阳离子角蛋白。将该阳离子角蛋白对几种常见的皮革助剂进行絮凝处理,考察其絮凝性能,同时,对絮凝得到的絮体进行适当处理,用于皮革填充,对回收利用的可行性进行初步探讨。该絮凝剂对染料的絮凝效果较好,脱色率可达到90%以上。絮体用于皮革填充,填充后皮革增厚率达15.12%,抗张强度从15.81 MPa提高到16.40 MPa,填充后坯革的断裂伸长率在较理想的范围,柔软度从5提升到8,丰满度从5提升到9,表现了理想的填充效果。     

聚硅氧烷改性树枝状聚合物的制备及应用

以端氢聚二甲基硅氧烷(HTPDMS)和烯丙基缩水甘油醚(AGE)为原料,利用硅氢加成反应合成出单端环氧基聚二甲基硅氧烷(SEPDMS),再将其接枝到一代树枝状聚酰胺-胺(G1 PAMAM)上,制备出聚硅氧烷改性的树枝状-线性聚合物(G1 PAMAM-Si)。通过傅里叶红外光谱(FTIR)、核磁共振氢谱(1HNMR)及纳米粒度分析仪表征分析了产物的结构及乳液性能。将G1 PAMAM-Si应用于皮革加脂工序,并使用扫描电镜(SEM)、X射线衍射谱图分析手段考察了加脂后皮革样品的结构与性能。结果表明,G1 PAMAM-Si加脂后革样胶原纤维间距增大,纤维排列无序度增加。柔软度增加至6.07 mm,抗张强度为17.43 MPa,且撕裂强度增加至94.97 N/mm。     

马铃薯淀粉改性阳离子絮凝剂的制备及其絮凝效果

以马铃薯淀粉为原料，经苛化后，与丙烯酰胺接枝聚合，再引入叔胺基团而制备絮凝剂（PSF）。探讨了PSF对高岭土悬浊液及工厂排泄废水的絮凝作用，以及投药量、体系pH值对絮凝效果的影响。实验表明：PSF对制糖及制革厂废水具有良好的絮凝作用。     

改性纳米Si3N4的制备及在PU合成革中的应用

采用自制的丙烯酸丁酯-甲基丙烯酸甲酯-乙烯基三乙氧基硅氧烷（BA-MMA-VTES）大分子表面改性剂对纳米氮化硅（Si3N4）陶瓷粉体进行表面包覆改性,将改性后的纳米Si3N4粉体加入到耐水解聚氨酯（Pu）树脂中成革,并进行傅立叶变换红外光谱、透射电子显微镜等分析及力学性能测试。结果表明,BA—MMA—VTES与纳米Si3N4发生化学健合;BA—MMA—VTES质量分数为5％时,纳米Si3N4粒径最小,改性后的纳米Si3N4有良好的分散性能。添加改性纳米Si3N4粉体的PU合成革的力学性能明显提高。     

Synthesis of PEGylated chitosan copolymers as efficiently antimicrobial coatings for leather

In this work, poly(ethylene glcycol)‐grafted chitosan (PEG‐g‐CS) was synthesized by conjugating PEG to the chitosan (CS) backbone. Such PEGylated CS copolymer was further characterized by FTIR and ¹H NMR, and the results demonstrated the successful synthesis. After PEGylation, the water solubility of CS was significantly improved due to the hydrophilicity of the PEG polymer. Therefore, this PEGylated CS was prepared as water borne coating for leather surface. The morphology and hydrophilicity of this coating on leather was studied by SEM and water contact angle measurement. Furthermore, the antimicrobial activity of PEGylated CS coating was investigated by measuring its minimum inhibitory concentration and the inhibition zone of coated leather against Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus, respectively. Compared to CS coating, such PEG‐g‐CS coating exhibited better antimicrobial property, which indicated the synergetic effect of the antimicrobial property of CS and the antiadhesive property of PEG. Thus, this PEGylated CS copolymer can be used as efficiently antimicrobial coating for leather product. © 2016 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43465.     

Construction of waste-collagen modified superfine fiber substrates based on “click” chemistry: Moisture absorption and permeability

Superfine fiber synthetic leather is a high-grade artificial leather product with numerous characteristics and advantages. However, compared with natural leather, it shows poor moisture absorption and moisture permeability, and it gives people a hot and tacky feeling; thus, the improvement of these properties has become a popular topic in the industry. In this paper, the “click” chemistry method was employed to modify the nylon fiber of the superfine fiber synthetic leather base with waste collagen to improve the moisture absorption and permeability of the superfine fiber synthetic leather base, thus enhancing the hygienic performance and wearing comfort of the end products, realizing waste recycling. This study obtained the optimal reaction conditions for the “click” modification of unfigured sea-island superfine fiber synthetic leather base with collagen methacrylamide. The characterizations by static contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy analysis confirmed that collagen was successfully grafted onto the surface of the nylon fiber. Compared with the original base, the moisture absorption, and permeability of the base were improved by 602.4% and 43%, respectively. This study shows the theoretical research significance and excellent practical value for the resource utilization of skin collagen waste.     

Synthesis and application of methyl methacrylate/butyl acrylate copolymer nanoemulsions as efficient retanning and lubricating agents for chrome‐tanned leather

Two different nano‐emulsions based on methyl methacrylate/butyl acrylate copolymers have been synthesized to be used as retanning and lubricating agents for chrome‐tanned leather. The main difference and characteristics of the two prepared copolymers were studied. The nano particle size of the two copolymers was confirmed using transmission electron microscope (TEM). The influence of the prepared copolymers on chrome‐tanned leather as retanning agents was investigated. The properties of the retanned leather, namely, physicomechanical properties as tensile strength, elongation at break and water absorption, were measured. Thermal gravimetric analysis (TGA) technique was used to examine the thermal stability of the retanned leather. Also, the texture of the grain surface and fibers were inspected using scanning electron microscope (SEM). The retanned leather showed an improvement in its physicomechanical properties, as well as enhancement of its thermal stability as compared with the chrome‐tanned leather. Furthermore, the retanned leather has uniform dyestuff, softness, and firmness of grain. All these promising results provide evidence to the applicability of the prepared copolymer emulsions as efficient retanning and lubricating agents for chrome‐tanned leather. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Comfort,chemical, mechanical,and structural properties of natural and synthetic leathers used for apparel

Natural leather is processed from hides and skins of animals. Synthetic leathers are becoming popular as an alternative material owing to limited availability and varying size of natural leathers. There is a need to understand the properties of natural and synthetic leathers to select proper material for an application. In this study, materials used for apparel application such as natural sheep nappa leather and synthetic polyurethane (PU)‐based leather have been chosen and analyzed for comfort, chemical, physical, and structural properties. It was found that natural sheep nappa leather has enhanced water vapor permeability whereas other comfort properties such as softness and drape ability are comparable to synthetic PU leather. Whereas synthetic PU leather dominated most of the physical properties, especially percentage elongation and stitch tear strength, in specific directions on account of polyester knitted base fabric. Chemical properties of natural sheep nappa leather and synthetic PU leather depended on the individual material composition and characteristics. Scanning electron microscopic (SEM) analysis provided convincing evidence for some of the quantified comfort and physical properties. The results of this study would be useful in selection of proper material for apparel application as well as in providing directions for future research in synthetic leather manufacture. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Natural rubber/leather waste composite foam: A new eco‐friendly material and recycling approach

This article describes a new approach of recycling the leather waste (shavings) using it as filler in natural rubber foams composites. The foams were prepared using different amounts of leather waste (0–60 parts per hundred of rubber) and submitted to morphological (SEM microscopy) and mechanical analyses (cyclic stress–strain compression). The increase of leather shavings on the composite causes an increase of viscosity in the mixture, which reflects in the foaming process. This results in smaller and fairly uniform cells. Furthermore, expanded rubber has the biggest cell size, with more than 70% of cell with 1000 µm, while the composite with the higher concentration of leather has around 80% of total number of cells with 100–400 µm. The mechanical parameters were found to depend on the leather dust concentration. Moreover, the stiffness rises with the increase of leather shavings; consequently, the compression force for expanded rubber was 0.126 MPa as well as the composite with higher concentration of leather was 7.55 MPa. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41636.     

Dyeing of chrome tanned collagen modified by in situ grafting with 2‐EHA and MAC

The aim of this study deals with the modification of the chrome tanned collagen (leather) by in situ grafting with 2‐ethyl hexyl acrylate (2‐EHA) and methacrylic acid (MAC) to improve its dyeability using Amecid Floxine 2GN (C.I. Acid Red 1) and Remazol Black B (C.I. Reactive Black 5). The optimum condition of in situ grafting has been evaluated. FTIR spectra of the ungrafted and the in situ grafted chrome tanned collagen showed that the corresponding band of the acrylate carbonyl ester occurs at 1730–1735 cm^?1 when compared with the ungrafted ones. The colorimetric data of the in situ grafted and dyed samples exhibited improvement in color shade, dye bath exhaustion, wash and light fastness relative to the ungrafted and dyed ones. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 174–179, 2006     

Production of leather‐like composites using chemically modified short leather fibers. I: Chemical modification by emulsion polymerization

In order to evaluate the possible use of short leather fibers to produce leather‐like composites, five kilograms of fibers (extracted from leather wastes) were modified by in situ emulsion polymerization of methyl methacrylate (MMA). This treatment was performed in order to increase the compatibility of leather fibers with several commodity polymers used in the shoe and furrier industries. The chemical modification was carried out by aqueous emulsion polymerization initiated by a redox system (potassium persulfate and sodium metabisulfite). The effects of the monomer and redox initiator content as well as the reaction temperature were evaluated. The modified short leather fibers were characterized by instrumental techniques such as Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), X‐ray Diffraction and Scanning Electronic Microscopy (SEM). The results show that the polymer is formed on the exterior of fibers (deposited fraction) as well as in the interior (by grafting or forming interpenetrated networks). The treatment significantly improves the thermal stability of fibers. It also reduces their water adsorption capacity, as a coating of PMMA is produced over the leather surface, as microscopic analysis has revealed. The last characteristic could be an advantage in certain applications.     

Production of leather-like composites using short leather fibers. II. Mechanical characterization

Leather-like composites were prepared by addition of chemically modified short leather fibers (SLF) into a plasticized polyvinyl chloride (pPVC) matrix. The fibers were subjected to chemical modification by emulsion polymerization to achieve good interfacial adhesion between SLF and the pPVC matrix. The SLF with chemical modification were obtained from three different reaction conditions where these SLF have different percentages of grafted and deposited PMMA polymer onto the fiber surface. The incorporation of the SLF into the thermoplastic matrix was carried out using a torque-rheometer and the composites obtained were molded by compression. Tensile and tear mechanical tests were performed on composite samples, and the morphology of the fractured surfaces was analyzed using scanning electron microscopy (SEM). The results show that the incorporation by grafting of polymethyl metacrylate (PMMA) onto the fibers produced a significant improvement of their interfacial adhesion to pPVC, promoting the compatibilization between the fiber surface and matrix. The findings are discussed and interpreted in terms of enhanced adhesion at phase boundaries. Overall, the results confirm that it is possible to produce modified leather composites based on a pPVC matrix, which exhibit relatively high tensile strength, tear resistance and flexibility. These composites are very suitable candidate materials for applications in the footwear industry.     

皮革涂饰剂的最新研究进展

首先介绍传统皮革涂饰剂的种类及其进展,详细论述了聚氨酯用做皮革涂饰剂的优异性能。重点讨论了紫外(UV)光固化皮革涂饰剂的发展历程和现状,及其相对于传统皮革涂饰剂的优势。并总结了皮革涂饰剂的发展趋势。     

Styrene and butyl methacrylate copolymers and their application in leather finishing

Homopolymers and copolymers of styrene and butyl methacrylate were synthesized with different ratios by an emulsion polymerization technique with K₂S₂O₈/NaHSO₃ as the redox initiation system and sodium dodecyl sulfate as the emulsifier at 60°C for 3 h. The effects of different monomer ratios on the kinetics of emulsion polymerization and polymer viscosity were studied. These copolymers were applied to leather surfaces with a hand coater to a thickness of 18 μm. The effects of the coatings on the leather surfaces were evaluated through the measurement of physical and mechanical properties of coated and uncoated leather. IR spectra showed new bands characteristic of styrene and butyl methacrylate, which disappeared in the spectrum of uncoated leather. The physical and mechanical results showed that the water absorption content decreased with increasing styrene content, and the water vapor permeability of the coated leather was less than that of the uncoated leather; however, it was still in the acceptable range. The results indicated improvements in the tensile strength and elongation (%) for the coated leather with increases in the butyl methacrylate content. Thermogravimetric analysis showed characteristic improvements in the thermal stability of leather after the coating; its optimum stability was reached when the leather was coated with poly(styrene:butyl methacrylate) (1 : 1). Finally, scanning electron microscopy showed the full grain surface of the leather. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of Fat-Liquor Based on Jojoba Oil Under Phase Transfer Catalysis

Jojoba oil is of immense importance for industrial applications. There are a lot of published articles concerning its various uses in cosmetics, detergents, surfactants and lubricants. Therefore, this work was devoted to exploring its application for further use in the leather industry as a fat-liquoring agent. The fat-liquoring process is one important step in leather manufacturing, with the intention of obtaining leather of full, soft handle, flexibility, and pliability as well as improving its mechanical properties. The study involved preparation of jojoba fat-liquor via a sulfitation process. An improvement of the sulfitation process based on combined SO₃ content was achieved under phase transfer catalysis (PTC). Two differently prepared types of phase transfer catalyst of phosphonium and ammonium types were investigated, namely, benzyl tri-phenyl phosphonium chloride (BTPP) and tri-ethyl benzyl ammonium chloride (TEBA). The fat-liquored leather led to an improvement in its mechanical properties such as tensile strength and elongation at break. In addition, a significant enhancement of the texture of the treated leather by jojoba fat-liquor as indicated in the scanning electron microscope (SEM) images was observed.     

基于咪唑型离子液体两性聚合物表面活性剂的合成及在皮革加脂中的应用

以N-乙烯基咪唑、溴代正己烷为原料，经亲核取代反应合成溴化1-己基-3-乙烯基咪唑（HVIMBr）。然后，以溴化1-己基-3-乙烯基咪唑（HVIMBr）、甲基丙烯酸二甲氨乙酯（DMAEMA）为原料，偶氮二异丁腈（AIBN）为引发剂，通过自由基聚合制备共聚物（p（DMAE-co-[HVIMBr))。之后，用1,3-丙磺酸内酯对共聚物进行季胺化改性合成两性聚合物p（DMAE-co-[HVIMBr)PS。采用红外光谱（FT-IR）和核磁共振（1H-NMR）对产物的结构进行表征。最后，将不同比例两性聚合物与蓖麻油复配后应用于皮革的加脂工序。使用环境扫描电子显微镜（E-SEM）和超景深显微镜等手段研究了加脂处理后白湿皮的结构与形貌，测定了加脂后皮革的柔软度及物理机械性能。结果表明，合成的两性聚合物p（DMAE-co-[HVIMBr)PS加脂剂处理皮革后，其柔软度和物理机械性能均有所提高。     

The Modification of Chrome Tanned Leather by Polyethylene Glycol-Linked Gemini Fatty Alcohol Phosphate

A series of polyethylene glycol-linked Gemini fatty alcohol phosphate surfactants (GFAP) were prepared with long chain n-alkanol (C = 8, 12, 16, 18), polyethylene glycol (PEG-200, PEG-400, PEG-600, PEG-800, PEG-1000) and phosphorus oxychloride (POCl₃). The structure of the prepared surfactants was characterized by Fourier transform infrared spectrometer (FT-IR). The surfactants were employed for the modification of chrome-tanned leather. The morphological changes of chrome-tanned leather and modified chrome-tanned leather were observed by scanning electron microscopy (SEM). The relationship between the alkyl chain length and molecular weight of the PEG and the hydrophobicity, softness, mechanical strength of modified chrome-tanned leather was also discussed. The experimental results showed that the mechanical strength and softness of modified chrome-tanned leather were enhanced with an increase of alkyl chain length, while the hydrophobicity, mechanical strength and softness were decreased with an increase of molecular weight of the PEG. The hydrophobicity, mechanical strength and softness of modified chrome-tanned leather were optimized for an alkyl chain length of 16. Therefore, 16–200 Gemini phosphate surfactants with an alkyl chain length of 16 and a PEG molecular weight of 200 have a good comprehensive modification effect on Chrome-tanned leather, the tensile strength, tear strength and softness of modified chrome-tanned leather are 57.07 N mm⁻², 79.49 N mm⁻¹, 9.73 mm, respectively.     

Physicochemical and thermal properties of phenol–formaldehyde‐modified polyphenol impregnate

Tannin, a natural polymer belonging to the polyphenolic group of compounds, is widely used in the leather industry, specifically as a tanning agent for the conversion of putrescible collagen fibers into leather matrix during the leather‐manufacturing process. Unspent tannin poses a serious environmental threat to the public because it has a very high half‐life, leading to groundwater pollution when discharged into soil. Attempts have been made to separate tannins through chemical means and recovered tannin needs to be encapsulated for its safe disposal. In the present study the recovered tannin was impregnated in phenol–formaldehyde (PF) resin. Spectroscopic and thermogravimetric (IR, NMR, TGA and DSC) studies revealed that the modified polyphenol was held physically in the impregnate. The impregnated matrix showed resistance to mineral acids, strong alkalis and organic solvents and was tested for its adhesive property on leather sheets. The leather that bonded with PF‐modified polyphenol impregnate (PFT) had a 27% increase in peel strength and a 40% increase in lap shear strength as compared to the sample bonded with PF resin. The corrosive resistance result of the PFT resin shows it has potential application as an anticorrosive paint in the paint industry. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1567–1571, 2001