离子液体/羊毛纤维/凝固剂三元相图的构建

三元相图是研究羊毛角蛋白再生过程热力学行为的有效工具.通过浊度测试和Boom经验方程构建离子液体(IL)/羊毛纤维/凝固剂浊点线性关系(LCP)曲线和三元相图,进一步系统地研究了凝固剂种类、再生温度和离子液体结构对羊毛角蛋白再生性能的影响规律.结果表明,羊毛角蛋白最优再生体系是1-乙基-3-甲基咪唑磷酸二乙酯([Emi...     

Preparation and characterization of Bombyx mori silk fibroin and wool keratin

Silk and wool are well‐known protein‐based fibers. Their environmental stability, biocompatibility, and unique mechanical properties provide an important basis for using these natural proteins in biomedical applications. To use them as biomaterials in the form of fibers, films, or membranes, it is necessary to characterize these proteins in their solution and solid states because structural characteristics and morphological features have a great influence on the physical and mechanical properties of these new regenerated protein forms. Therefore, in the present study, silk fibroin and wool keratin were dissolved and their solution behaviors and secondary structures are analyzed and compared, using particle size distribution, molecular weight distribution (SDS‐PAGE), Fourier transform infrared, and X‐ray diffraction techniques. It was shown that keratin is more stable in solution and more amorphous in the solid state. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:4260–4264, 2006     

羊毛角蛋白-聚乙烯醇再生纤维的结构性能表征

从废旧毛涤混纺面料中提取出羊毛角蛋白,配制角蛋白含量不同的3种纺丝液,通过静电纺丝方法得到羊毛角蛋白-聚乙烯醇(PVA)再生纤维。用扫描电镜观察、红外光谱分析及热学性能分析发现:3种羊毛角蛋白-PVA再生纤维膜中的纤维分布均匀、相互交叉,直径在230~260 nm左右;3种再生纤维的红外光谱都具有明显的角蛋白与PVA的特征;3种再生纤维膜的热稳定性差异不大。     

Chemical modification of wool fibers with acid anhydrides

Wool fibers were chemically modified by reaction with succinic and glutaric anhydrides. The weight gain (and acyl content) increased with increasing the reaction temperature (65–80°C) and time (1–2 h), attaining 18.9% (158.9 mol/10⁵ g) and 23% (163.9 mol/10⁵ g) for succinylated and glutarylated wool, respectively. Changes in the amino acidic pattern of acylated wool, i.e., decrease of basic amino acid residues and formation of ornithine, were observed by acid hydrolysis. The X‐ray diffraction profiles of modified wool fibers remained essentially unchanged, suggesting that the crystalline structure was not affected by reaction with acid anhydrides. The degree of molecular orientation of acylated wool slightly decreased, especially at high weight gain. The viscoelastic response of wool modified with succinic and glutaric anhydrides was characterized by a shift to a lower temperature of both the drop of the storage modulus and the peak of the loss modulus. These features are indicative of a higher mobility of the keratin chians in the amorphous and crystalline domains. In fact, it is suggested that the chemical agent diffused into the accessible parts of α‐crystallites, reaching the available reactive sites. This did not cause changes in the crystalline pattern of wool, but resulted in a different thermal behavior of fibers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1573–1579, 1999     

Studies of wool keratin by EPR spectroscopy

Electron paramagnetic resonance (EPR) tests were conducted on four kinds of interrelated samples—natural undyed wool fibers (SW3, SW5), fibers dyed with model direct dyes (1W, 5W), fibers treated destructively with formic acid for descaling and dyed with the same dyes (K1W, K5W), and the dyes themselves (1%). For all samples, a radical signal of g = 2.007 was detected. The presence of Mn²⁺ and Fe³⁺ ions in the wool fiber structure was postulated. Modifications of disulfide regions of fiber matrix were also analyzed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1459–1465, 2006     

Preparation and properties of keratin–poly(vinyl alcohol) blend fiber

Keratin–poly(vinyl alcohol) (PVA) blend fibers containing 13–46 wt % of –SSONa⁺ (S‐sulfo) keratin were prepared by the wet‐spinning technique. They were formed by dehydration of an aqueous solution of S‐sulfo keratin and PVA (spinning dope) in a coagulation bath of sodium sulfate–saturated solution and subsequently drawn. Keratin–PVA fibers showed higher tenacity than that of wool, presumably originating from the high mechanical strength of the PVA component. The heat treatment at about 200°C improved the waterproof characteristics such as shrinkage of keratin–PVA fibers more conspicuously than did PVA fibers. That is, after heat treatment at 195°C for 10 min, keratin–PVA blend fiber shrank 20% in water at 60°C, whereas PVA fiber shrank 56%. Differential thermal analysis suggested the crosslinking of disulfide bonds between keratin molecules during the heat treatment, whereas the additional crystallization of PVA component was not observed. Adsorption of heavy metal and toxic gas to keratin–PVA fibers was also investigated. Keratin–PVA fiber was found to adsorb Ag⁺ and formaldehyde gas more efficiently than PVA. Thus, blends of keratin and PVA were advantageous for both polymer fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 756–762, 2004     

Silica-Supported Ionic Liquids Prompted One-Pot Four-Component Synthesis of Pyrazolopyranopyrimidines, 3-methyl-4-aryl-4,5-dihydro-1H-pyrano[2,3-c]pyrazol-6-ones,and 1,6-diamino-2-oxo-1,2,3,4-tetrahydropyridine-3,5-dicarbonitriles

Three methods have been used for synthesis of pyrazolopyranopyrimidines, 3-methyl-4-aryl-4,5-dihydro-1H-pyrano[2,3-c]pyrazol-6-ones, and 1,6-diamino-2-oxo-1,2,3,4-tetrahydropyridine-3,5-dicarbonitrile derivatives via four-component reactions under solvent-free conditions. Silica-bonded 5-n-propyl-octahydro-pyrimido[1,2-a]azepiniumchloride (SB-DBU⁺Cl^?), silica-bonded n-propyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride (SB-DABCO⁺Cl^?), and nano silica-bonded 5-n-propyl-octahydro-pyrimido[1,2-a]azepinium chloride (NSB-DBU⁺Cl^?) as silica-supported ionic liquids catalyzed these reactions. These green, heterogeneous catalysts are separated from the reactions by simple filtration. The catalysts were recovered for at least four times without significant loss of their catalytic activities.     

Tuning the Extractive Properties of Purex Solvent using Room Temperature Ionic Liquid

An Aliquat-336 based ionic liquid, namely, tri-n-octylmethylammonium bis(2-ethylhexyl)phosphate ([A3636]⁺[DEHP]^?) was prepared and studied for the extraction of U(VI), Pu(IV), and Am(III) from nitric acid medium. Since the ionic liquid, [A336]⁺[DEHP]^? was miscible in n-dodecane (n-DD), the extraction of these actinides in the PUREX solvent, 1.1 M tri-n-butylphosphate (TBP) in n-dodecane (n-DD), was investigated in the presence of small concentrations of ionic liquid. The distribution ratio of U(VI) and Am(III) in 0.03 M [A336]⁺[DEHP]^?/n-DD decreased with increase in the concentration of nitric acid; whereas the extraction of Pu(IV) initially increased, it reached a maximum at 4 M nitric acid followed by the decrease. The extraction of actinides in ionic liquid medium decreased in the order Pu(IV) > U(VI) >> Am(III), indicating the feasibility of modifying the extractive properties of TBP/n-DD to favor Pu(IV) extraction. Therefore, the extraction of Pu(IV) in a solution of TBP – [A336]⁺[DEHP]^? in n-DD was also studied. The distribution ratio of Pu(IV) increased with increase in the concentration of ionic liquid and decrease in the concentration of TBP in organic phase. The distribution ratio of Pu(IV) determined in the presence of small concentration of ionic liquid in 1.1 M TBP/n-DD was always much higher than that observed in 1.1 M TBP/n-DD. In contrast to this, the distribution ratio of U(VI) decreased by the addition of ionic liquid and Am(III) was inextractable even in the presence of ionic liquid.     

Infrared spectroscopy of graft polymers separated from graft copolymers of wool and silk with methyl methacrylate

The HCl- or papain-decomposition residues obtained from reduced wool fibers grafted with 1.5–3.0% methyl methacrylate were extractively fractionated successively with cold acetone, hot acetone, and benzene. Each fraction was examined by infrared spectroscopy. Generally, the 715 cm^?1 spectral band considered to be due to vc-s-c was found in the hot acetone-soluble fraction. It was concluded that the thiol groups on wool keratin provide the main sites of grafting, as might be expected. A similar result was obtained for grafted silk fibroin fibers, the methionine residue being presumed to be related to some of the grafting sites at least. Furthermore, a sort of stereoregularity was observed in some of the graft polymer fractions, isotactic-rich material being obtained in the case of silk fibers. In the range of very low grafting, a stereoregulating effect on the structure of the polymer formed within fibers appears to be present in relation to the grafting or adsorption sites of monomers and the fine structure of fibers.     

An eco-friendly method based on the self-glue effect of keratins for preparing Fe3O4-coated wool

Although coating technology and in-situ synthesis have been widely applied to produce Fe₃O₄ NPs-containing composite materials, there still exist potential risks to the environment. Herein, an eco-friendly preparation of Fe₃O₄ nanoparticles (FNPs)-coated wool felt is proposed based on the self-glue effect of wool keratins in the NaHSO₃/urea solution. It avoids the use of coating agents, and also the commercially available FNPs are directly utilized as raw materials, both making the residual FNPs completely recyclable. The resulting FNPs-coated wool felt shows high magnetization (23.54 emu g⁻¹) and excellent microwave-assisted heating properties (the temperature rise is about 40°C after 10 min). The results of EDS-SEM (energy dispersive spectrometer-scanning electron microscope), loud amount (%), crease recovery angle (CRA), Fourier transform infrared (FTIR) spectrometer and X-ray diffraction (XRD) prove that the dramatical swelling and the recoagulation of superficial keratins of wool fibers are the mechanism of the self-glue effect.     

羊毛角蛋白液涂覆处理涤纶的亲水性研究

利用三羧乙基膦(TCEP)和亚硫酸氢钠溶解羊毛制备羊毛角蛋白溶液;采用羊毛角蛋白液涂覆处理涤纶,改善涤纶的亲水性,结果表明:采用体积分数为10%的羊毛角蛋白液涂覆处理涤纶织物,织物平均增重率大于9%,织物的回潮率由0.57%提高到7.16%.吸湿性明显改善;采用TG酶交联角蛋白液涂覆处理织物,可改善其耐洗性;TC酶交联角蛋白的最佳工艺为:TG酶用量1 g,交联时间5 h,交联液pH值为7;经扫描电镜观察和X射线光电子能谱分析,羊毛角蛋白对涤纶有很好的粘附     

Dyeing behaviors of ionic liquid treated wool

In this article, a new class of “green” solvent—ionic liquid (IL) was employed to improve the dyeability of wool. The physical and chemical properties of the IL‐treated wool, such as surface morphology, wettability, and tensile strength were first analyzed, and then the dyeing properties of IL‐treated wool were investigated in terms of dyeing rate, dyeing exhaustion at equilibrium, color depth, and color fastnesses. The scanning electron microscope (SEM) images showed eroded marks on IL‐treated wool fiber surfaces. The water contact angle of the fabric treated with IL at 100°C decreased from 118.6° to 106.4°. The tensile strength of IL‐treated wool fibers was slightly decreased when the treating temperature was less than 100°C. Dyeing kinetics experiments revealed that the IL treatments greatly increased initial dyeing rate, shortened half‐dyeing time, and time to reach dyeing equilibrium. The final exhaustion and color depth of IL‐treated wool were also increased accompanying with slightly decreased color fastness. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Modification of surface properties of wool fabric with linde type a nano‐zeolite

Wool is a naturally occurring composite fiber consisting of keratin and keratin‐associated proteins as the key molecular components. The outermost surface of wool comprises a lipid layer that renders the surface hydrophobic, which hinders certain fabric processing steps and moisture management properties of wool fabrics. In this study, Linde Type A (LTA) nano‐zeolite (a Na⁺‐, Ca²⁺‐, and K⁺‐exchanged type A zeolite) was integrated onto the surface of wool using 3‐mercaptopropyl trimethoxy silane as a bridging agent. The resultant surface morphology, hydrophilicity, and mechanical performance of the treated wool fabrics were evaluated. Notably, the surface hydrophilicity of wool increased dramatically. When wool was treated with a dispersion of 1 wt % zeolite and 0.2 wt % silane, the water contact angle decreased from an average value of 148° to 50° over a period of approximately 5 min. Scanning electron microscopic imaging indicated good coverage of the wool surface with zeolite particles, and infrared spectroscopic evaluation demonstrated strong bonding of the zeolite to wool keratins. The zeolite application showed no adverse effects on the tensile and other mechanical properties of the fabric. This study indicates that zeolite‐based treatment is potentially an efficient approach to increasing the surface hydrophilicity and modifying other key surface properties such as softness of wool and wool fabrics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42392.     

Kinetics of graft copolymerization of methyl methacrylate in wool fibers

The graft copolymerization of methyl methacrylate in wool fibers was investigated in the aqueous LiBr–K₂S₂O₈ system without homopolymer. The rate of grafting and the degree of polymerization of graft polymer were determined on varying the extent of reduction of wool fibers and the concentration of monomer. From the graft copolymerization behavior observed at a given concentration of redox catalysts (LiBr and K₂S₂O₈), the thiol groups in wool fibers were considered to play a role as a sort of catalyst of polymerization, not as the chain transfer agent, and also to give the grafting sites. So, the initiation process of grafting was assumed to be started by d[S·]/dt = k_i[SH]_eff, and the kinetic consideration was found to lead to the following expression in agreement with the experimental results: 1/DP = (k_t/k_p²[M]_fib²)R_p, where d[S·]/dt is the rate of formation of thiol radicals by radicalotropy to ? SH from SO₄^?., OH·, or Br·; k_i, k_p, and k_t are the rate constants of initiation, propagation, and termination, respectively; [SH]_eff and [M]_fib are the concentration of the effective thiol groups and the MMA monomers within the wool fibers, respectively; DP is the average degree of polymerization of graft polymers, and R_p the overall rate of grafting.     

Crosslinking structure of keratin. I. Determination of the number of crosslinks in hair and wool keratins from mechanical properties of the swollen fiber

Hair and wool keratin fibers which had been treated with an 11 M LiBr solution containing N-ethyl maleimide showed typical rubberlike elasticity in a solution composed of equal volume of 8 M LiBr and diethylene glycol mono-n-butyl ether. Stress–strain curves and equilibrium force–temperature relations were measured for swollen hair and wool fibers. The non-Gaussian effects on deformation and the energy component in retractive forces were analyzed. On the basis of rubber elasticity theory, a method for estimation of the number of mechanically effective crosslinks in keratin fibers was proposed. A linear relationship between the crosslink density and the disulfide content was obtained from the data for a variety of keratin fibers (i.e., two different human hairs, horse hair, and 17 different wools). From the results of thermodynamical and non-Gaussian treatments for swollen keratin, it was suggested that the swollen fiber consists of a two-phase structure: a mechanically stable phase of higher crosslinked domains and rubbery phase with lower crosslink density. It was further found that considerable amounts of nondisulfide covalent crosslinks are present in wool and hair keratins.     

Investigations on esterification reactions of starches in 1‐N‐butyl‐3‐methylimidazolium chloride and resulting substituent distribution

The ionic liquid (IL) 1‐N‐butyl‐3‐methylimidazolium chloride ([C₄mim]⁺Cl^?) was used as solvent for different esterification reactions of the biopolymer starch. Therefore, maize starches with varying content of amylose were used. Different carboxylic acid anhydrides were applied to esterify starch with a degree of substitution (DS) in the range of 0.7–3.0. For example, starch acetates with the mentioned DS are accessible within 30 min at a 105°C‐reaction temperature. The DS distribution of starch acetates synthesized in IL was compared with the common starch acetate synthesis of Mark and Mehltretter. Also, a consideration of starch acetates and cellulose acetates synthesized in [C₄mim]⁺Cl^? is given. The starch esters were characterized by means of Raman spectroscopy for qualitative‐ and nuclear magnetic resonance spectroscopy for quantitative determination of the functionalization pattern. Moreover, the molecular mass distribution was determined after saponification by means of GPC‐MALLS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Regenerated cellulose membrane prepared with ionic liquid 1‐butyl‐3‐methylimidazolium chloride as solvent using wheat straw

BACKGROUND: Currently, cellulose membranes are prepared by cellulose acetate hydrolysis or chemical derivatization dissolution and regeneration using cotton pulp or wood pulp. In this study, the concept ‘lignocelluloses biorefinery’ was used, and good quality long fiber was fractionated from wheat straw using clean technologies. The objective of this study is to develop wheat straw cellulose to prepare regenerated cellulose membrane with ionic liquid 1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl) as solvent. RESULTS: Wheat straw cellulose (WSC) fractionated from wheat straw contained 93.6% α‐cellulose and the degree of polymerization (DP) was 580. WSC was dissolved directly without derivatization in [BMIM]Cl. With increase in dissolving temperature, the DP of the regenerated cellulose dropped, which resulted in a decrease in the intensity of regenerated cellulose membrane. After regeneration in [BMIM]Cl, the WSC transformed from cellulose I to cellulose II, and the crystallinity of the regenerated cellulose was lower than the original cellulose. The regenerated WSC membrane had good mechanical performance and permeability, the tensile strength and breaking elongation were 170 MPa and 6.4%, respectively, the pure water flux was 238.9 L m^?2 h^?1 at 0.3 MPa pressure, and the rejection of BSA was stabilized at about 97%. CONCLUSION: Wheat straw cellulose fractionated from wheat straw satisfied the requirement to prepare regenerated cellulose membrane using ionic liquid [BMIM]Cl as solvent. Copyright © 2012 Society of Chemical Industry     

Isobaric vapor-liquid equilibrium for methanol+benzene+1-octyl-3-methylimidazolium tetrafluoroborate

Isobaric vapor-liquid equilibrium (VLE) data for {methanol (1)+benzene (2)+1-octyl-3-methylimidazolium tetrafluoroborate (3)} where 3 is an ionic liquid ([OMIM]⁺[BF₄]^?) at atmospheric pressure (101.32 kPa) were measured with a modified Othmer still. The results showed that the ionic liquid studied can transfer the azeotropic point and eliminate the azeotropic phenomena when its concentration is up to x₃=0.30. This means that [OMIM]⁺[BF₄]^? can be used as a promising entrainer in the application of extractive distillation. The measured ternary data were correlated using the NRTL model.     

Properties of wool fibers treated under high-temperature water and steam

In this study, we investigated the hygroscopicity and the extension properties of wool fibers treated under high-temperature steam and water. The scale structure and the crystallinity of the treated wool fibers were analyzed with scanning electron microscopy and X-ray diffraction analysis. The experimental results show that the hygroscopicity of the wool fibers treated under high-temperature steam was higher than that of the wool fibers treated under high-temperature water. The strength, the breaking elongation, and the breaking work of the treated wool fibers decreased obviously compared with the untreated wool fibers. The scale surface became rough and the crystallization index decreased for the treated wool fibers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Characterization of nanoscale wool particles

Nanoscale wool particles were prepared from wool fibers by a special pretreatment with the aid of specially designed machinery and techniques. Scanning electron micrographs showed that the particle sizes of wool powders produced from wool fibers approximately 8–20 μm in diameter decreased from a microscale to a nanoscale after three stages of pulverization, which were further confirmed with a laser particle size analyzer. Fourier transmission infrared analysis showed that there were no substantial changes in the chemical structure of the wool after the pulverization processes. The wool powders after the second and third pulverizations slightly differed from that of the wool fiber and the particles after the first pulverization, with greater amounts of the secondary amine groups, amide groups, C?S stretching vibrations, and O? H bonds. X‐ray diffraction analysis showed that the crystallinity of the wool powders decreased when the particle sizes decreased, particularly at nanoscales. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 803–808, 2007