Modification of wool fabric using ecologically acceptable UV‐assisted treatments

Wool fabric was modified using ecologically acceptable treatments in order to enhance its shrinkage and pilling resistance. Wool fabrics were irradiated with ultraviolet light for different period of times. The UV‐irradiated wool fabrics were then treated with an oxidising agent (hydrogen peroxide or sodium monoperoxyphthalate) or a protease enzyme (papain or savinase 16L type EX). Treatment of wool fabric with these systems was found to be effective in reducing its pilling and shrinkage without severe loss in weight and strength of the fabric. Chemical and mechanical analyses of the treated samples compared with the untreated one are reported. Transmission electron microscopy investigation of the untreated and treated wool samples was used to identify the histological component in wool keratin affected by these treatments. Copyright © 2005 Society of Chemical Industry     

Supercritical carbon dioxide‐assisted loosening preparation of dry leather

The 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     

Direct coloration of textiles with photochromic dyes. Part 3: dyeing of wool with photochromic acid dyes

Wool dyed with two isomeric water‐soluble spirooxazine‐based photochromic acid dyes, which were specifically designed and synthesised for direct application to protein and polyamide substrates, showed reversible change from a pale yellowish colour to blue when exposed to sunlight or UV light. With the first dye, significantly higher photochromic colour change was obtained when the wool was bleached, a feature attributed to a more open fibre structure which may facilitate penetration of the non‐planar dye anion and also the photocoloration reaction which requires a change in molecular geometry. Experimentation demonstrated that the optimum conditions for application of this dye to wool was from an aqueous dyebath at neutral pH and a temperature of 60 °C. An investigation using HPLC demonstrated that the dye was susceptible to decomposition in aqueous solution at higher temperatures and at lower pH values. The second dye was also applied to wool fabric to give a fabric with similar photochromic properties. The technical performance of the dyed fabrics, in terms of washfastness and photostability, was assessed.     

Cassava starch‐based nanocomposites reinforced with cellulose nanofibers extracted from sisal

Cellulose nanofibers were extracted from sisal and incorporated at different concentrations (0–5%) into cassava starch to produce nanocomposites. Films' morphology, thickness, transparency, swelling degree in water, water vapor permeability (WVP) as well as thermal and mechanical properties were studied. Cellulose nanofiber addition affected neither thickness (56.637 ± 2.939 µm) nor transparency (2.97 ± 1.07 mm^?1). WVP was reduced until a cellulose nanofiber content of 3.44%. Tensile force was increased up to a nanocellulose concentration of 3.25%. Elongation was decreased linearly upon cellulose nanofiber addition. Among all films, the greatest Young's modulus was 2.2 GPa. Cellulose nanofibers were found to reduce the onset temperature of thermal degradation, although melting temperature and enthalpy were higher for the nanocomposites. Because cellulose nanofibers were able to improve key properties of the films, the results obtained here can pave the route for the development and large‐scale production of novel biodegradable packaging materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44637.     

磺化改性玉米秆杂多糖的制备及其分散性能

玉米秆经萃取和初步分离得到玉米秆杂多糖(PS),以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为磺化试剂,以水为溶剂,过硫酸铵为引发剂,碱性条件下反应,得到玉米秆杂多糖的磺化衍生物(PS-AMPS),其结构由FTIR光谱分析证实;借助沉降体积法和吸光光度法,对磺化杂多糖的分散性能进行了评价。结果表明,当超细碳酸钙的质量浓度为4.0～8.0 g/L时,使用30 mg/L的磺化杂多糖可以取得良好的分散稳定作用;而对于含有10 mg/L铁、250 mg/L的钙(以CaCO3计),pH=9.0的水体,15 mg/L的磺化杂多糖能给出很好的分散效果;通过测定CaCO3悬浮液的Zeta电位和沉降颗粒的傅里叶变换红外光谱(FTIR)变化,对玉米秆杂多糖磺化衍生物的分散机理。研究表明,其分散机制是吸附分散机理。     

Recovering oil from corn ethanol fermentation by‐products

Removing oil from by‐products of corn fermentation is desirable for improving feed quality and providing an alternative source of oil for biodiesel production. We are investigating ways to increase oil removal by centrifugation during the typical dry grind fermentation process. We have to first make oil or oil containing “bodies” go into the liquid phase and then free the oil so it can be separated by centrifugation. This report outlines our research approaches and results.     

Microwave‐assisted synthesis of polyglycerol from glycerol carbonate

Microwave irradiation of glycerol carbonate allows formation of glycidol, which readily polymerizes to form polyglycerol under mild conditions comparatively to the classical polyetherification reaction involving high temperature and basic conditions. Analysis of the crude reactional mixture indicated the presence of low‐molecular weight oligomers constituted mainly of di, tri, and tetraglycerols with small quantities of higher molecular weights oligomers. Molecular size distribution was relatively similar to that of polyglycerols obtained under basic condition, even if these latter contained slightly higher amounts of high‐molecular weight oligomers. Structure of oligomers differs slightly according to the conditions of polymerization, and polyglycerols are obtained under microwave activation containing higher contents of cyclic isomers, whereas polyglycerols obtained under basic conditions contain more ramified isomers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Self-detergence of raw wool. I. ‘Suint scouring’

The degree of partial detergence accomplished by passing representative subsamples of several lots of greasy wools at controlled alkaline pH values (generally constant in each experiment) through the same bath of water at 50°c has been followed by estimations of loss of grease as well as loss of all soiling materials. The degree of detergence usually tends to rise to a maximum and then often falls off as is usual when detergent concentration is increased in other systems. As the pH of the detergence is raised, the maximum attained rises and the fall-off generally occurs earlier, at least up to pH 10.0. The course of detergence varies with the kind of alkali and its purity. Inorganic salts and amyl alcohol raise the maximum and increase the rate of fall-off of the self-detergence. Other methods of raising the degree of detergence are explored. The maintenance of maximum detergence for all wools is a complex problem.     

Enzyme‐assisted water‐extraction of oil and protein from rice bran

Enzymatic water‐extraction of oil and proteins from rice bran was studied in a laboratory‐scale set‐up. The effects of the following enzymes – Celluclast 1.5L, hemicellulase, Pectinex Ultra SP‐L, Viscozyme L, Alcalase 0.6L and papain – on oil and protein extraction yields, and the level of reducing sugars in the extract were investigated. The results showed that Alcalase was most effective in enhancing oil and protein extraction yields. Papain was found to be superior to all carbohydrase enzymes but it gave lower yields than Alcalase. Celluclast 1.5L, hemicellulase, Pectinex Ultra SP‐L and Viscozyme L did not affect yields significantly but increased the level of reducing sugars in the extract. © 2002 Society of Chemical Industry     

Fatty acid compositions of lipids from corn and grain sorghum kernels

Summary Characteristics and fatty acid compositions of the lipid components of the main fractions (germ, starch, gluten, and fiber) obtained in the wet milling of corn and grain sorghum kernels have been determined. The various lipids exhibited differences in chemical characteristics and fatty acid composition. These differences were found to be similar in both grains. Germ fats were the most unsaturated, contained the least free fatty acids and the least unsaponifiable matter. Starch fats were 70 to 90% free fatty acids and contained large amounts of palmitic acid. Gluten and fiber fats contained up to 32% unsaponifiables and about 20% free fatty acids.     

Characterization of polyurethane foams prepared from non‐pretreated liquefied corn stover with PAPI

Polyurethane foams were prepared through co‐polymerization of non‐pretreated liquefied corn stover (LCS) and polymethylene polyphenylisocyanate (PAPI). The effects of [NCO]/[OH] ratio on the chemical structure and the thermal properties were studied by means of Fourier transform infrared spectroscopy (FT‐IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The urethane linkages and the free isocyanate groups in co‐polymerization were detected from FT‐IR analysis. Thermal decomposition of polyurethane foams occurred in four main successive stages. With the increasing [NCO]/[OH] ratio, the glass transition temperature (T_g) and the initial decomposition temperature increased from −36.12 and 52.18 to 1.20 and 73.30°C, respectively. And the range of T_g expanded from 26.39 to 57.12°C.     

Carbon fibers derived from UV‐assisted stabilization of wet‐spun polyacrylonitrile fibers

A rapid, dual‐stabilization route for the production of carbon fibers from polyacrylonitrile (PAN) precursor fibers is reported. A photoinitiator, 4,4′‐bis(diethylamino)benzophenone, was added to PAN solution before the fiber wet‐spinning step. After a short UV treatment that induced cyclization and crosslinking at a lower temperature, precursor fibers could be rapidly thermo‐oxidatively stabilized and successfully carbonized. Scanning electron microscopy micrographs show no deterioration of the microstructure or hollow‐core formation in the fibers due to UV treatment or presence of photoinitiator. Fast‐thermally stabilized pure PAN‐based carbon fibers show hollow‐core fiber defects due to inadequate thermal stabilization, but such defects were not observed in carbon fibers derived from fast‐thermally stabilized fibers that contained photoinitiator and were UV treated. Tensile testing results confirm that fibers containing 1 wt % photoinitiator and UV treated for 5 min display higher tensile modulus than all other sets of thermally stabilized and carbonized fibers. Wide‐angle X‐ray diffraction results show a higher development of the aromatic structure and molecular orientation in thermally stabilized fibers. No significant increase in interplanar spacing or decrease in crystals size were observed within the UV‐stabilized carbon fibers containing photoinitiator, but such fibers retain a higher extent of molecular orientation when compared with control fibers. These results establish for the first time, the positive effect of the external addition of photoinitiator and UV treatment on the properties of the PAN‐based fibers, and may be used to reduce the precursor stabilization time for faster carbon fiber production rate. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40623.     

Polyurethane modified with 3‐aminopropyltriethoxysilane as wool antifelting agent

A wool antifelting agent containing polyurethane modified with 3‐aminopropyltriethoxysilane (APTES) was synthesized. Firstly an isocyanate ( NCO) group ended prepolymer was gained by a hydrogen shift reaction between isophorone diisocyanate (IPDI) and poly (propylene oxide triol) (PPT), and then NCO‐group of the prepolymer was blocked by 3‐aminopropyltriethoxysilane to form a precursor PPT‐[Si(OEt)₃]₃. After that a sol of the precursor was prepared for an antifelting agent. During heating the sol gelled and formed inorganic–organic hybrid film that was characterized by using FTIR and TGA. And then the wool fabric samples were treated with sol by pad‐dry‐cure process at different curing temperature (120, 140, and 160°C). The antifelting effects of different curing temperatures were compared. The results indicated that the new agent could endow a better antifelting effect with the low curing temperature at 120°C and 3 min. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polyelectrolyte‐assisted removal of metal ions with ultrafiltration

The water‐soluble polymers poly(styrene sulfonic acid‐co‐maleic acid) and poly(acrylic acid‐co‐maleic acid) were investigated with respect to their metal‐ion‐binding ability with ultrafiltration. The studied metal ions included Ag(I), Cu(II), Ni(II), Co(II), Ca(II), Mg(II), Pb(II), Cd(II), Zn(II), Al(III), and Cr(III) ions. The retention properties of the polyelectrolytes for the metal ions depended strongly on the ligand type. As for the carboxylate ligands, with increasing concentration and pH, the metal‐binding affinity increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1091–1099, 2005     

Mechanism involved in the dyeing of wool with an oil‐in‐water microemulsion system

This article investigates the influence of oil‐in‐water (o/w) microemulsions, used as media for both dye solubilization and dye baths, on the dye uptake on fiber surfaces. An acetic acid solution/Synperonic L7/benzyl alcohol microemulsion system was used to solubilize a water‐insoluble antimicrobial natural dye (C.I. Natural Orange 2) and to dye wool fabric at an acidic pH. The results clearly show that the dye exhaustion on the fabric took place mainly when the temperature of the dye bath promoted a change in the molecular organization of the microemulsions with the liberation of the dye solubilized in the oil droplets of the microemulsions. Although uniformly and evenly dyed fabrics were obtained, they showed very low wash fastness. To confirm the mechanism involved and to achieve dyed fabrics with good wash‐fastness properties, two different dyeing methods were also studied. The first method was dyeing at a constant low temperature, at which the o/w microemulsion remained a monophase system; the second one was dyeing at a high temperature, at which it was transformed into a multiphase system. Both the dye exhaustion and wash fastness improved considerably for the fabrics dyed at a high temperature. Moreover, uniform and even dyeing was achieved. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

UV‐assisted screen‐printing of flat textiles

An approach to printing of flat textiles is presented in this work. A screen‐printing method was applied on a cotton fabric. An aqueous printing paste was prepared from thickening and crosslinking agents and an ultraviolet‐sensitive tetrazole ring‐based compound of 2,3,5‐triphenyltetrazolium chloride or nitrotetrazolium blue chloride. After the printing process, a pattern was just visible with the naked eye. The development of colour occurred after exposure of the textile to ultraviolet light of 253.7 nm and was caused by the transformation of 2,3,5‐triphenyltetrazolium chloride or nitrotetrazolium blue chloride salts into the corresponding formazans, which are insoluble in water. The printed designs were resistant to washing. The stability of the colour of the samples is discussed in the case of prolonged irradiation, both with ultraviolet light of 253.7 nm and with daylight. This method of printing is a recent proposition for creative textile designing. It also seems to indicate a likely type of dye that may be further developed as potentially attractive for ultraviolet‐assisted printing or dyeing of textiles.     

Microwave‐assisted immobilization of lipase from Candida rugosa on Eupergit® supports

BACKGROUND: Immobilization of lipase (triacylglycerol acylhydrolase EC 3.1.1.3) from Candida rugosa on Eupergit^® C and Eupergit^® C 250L was performed under microwave irradiation in order to reduce immobilization time. Lipase loading, hydrolytic activity, esterification activity and operational stability in organic solvent of immobilized lipase preparation were determined. RESULTS: The microwave‐assisted procedure resulted in a 29% lower lipase loadings, compared with immobilized lipase obtained without microwaves. In hydrolytic activity assay, lipase immobilized under microwaves exhibited a 23% higher specific activity. Slight activation of lipase by microwave‐assisted immobilization was observed, since specific activity was around 5% higher than for free lipase. Lipase of highest activity was obtained after 2 min immobilization on Eupergit^® C. The same preparation exhibited high esterification activity in organic medium and a half life of 212 h was determined in multiple use assay. CONCLUSION: The application of microwave irradiation leads to reduction of immobilization time from 2 days to only 2 min. The immobilized lipase obtained has prospects for further application due to its high retained activity and stability. Copyright © 2009 Society of Chemical Industry