Function of lipase in lipid soil removal as studied using fabrics with different chemical accessibility

Fatty stain removal is enhanced by the inclusion of lipase in washing compounds and leads to increased lipid removal from within the fibers. Cotton fabrics with varied morphology/chemistry were investigated to study the accessibility of soil in textiles to detergent and lipase. Three cotton fabrics (untreated, mercerized, and carboxymethylated cotton), differing in chemical accessibility, and Tencel^TM lyocell fabric, a microdenier manufactured cellulosic fiber, were subjected to three treatments—unwashed, washed with detergent, and washed with lipase—so as to understand further the effects of fiber morphology on lipase effectiveness. Both detergents and lipase removed more soil from the more chemically accessible and hydrophilic textiles. Lipase increased lipid removal for all fabrics and all morphological locations on the fiber, including fiber surfaces, interfiber capillaries, small capillaries, and the center of the yarn bundle. Lipase removed significant quantities of soil from the lumen in untreated and mercerized cotons; these fabrics showed the largest total increases in amount of lipid removed by lipase. When the fiber surfaces were smoother and the fiber structure was less open and not carboxymethylated, i.e., the mercerized cotton fabric, more lipase benefit was observed (72% of the residual soil left after washing with detergent was removed when lipase was added). The total soil removal from the mercerized cotton fabric by use of lipase was equal to that observed for the more open, hydrophilic carboxymethylated fabric and for the Tencel, which has no lumen or other morphological features of natural cotton such as crenulations. Lipase appeared to enhance lipid removal under conditions where removal by the detergent surfactant system was limited. Furthermore, we concluded that lipase acted to remove lipid soil from within the fibers by functioning at the interior surfaces of microfibrils and pores within the fiber structure at the lipid-water interface.     

Lipid distribution on textiles in relation to washing with lipases

Effectiveness of lipase in detergency was studied using three test soils (lard, artificial sebum, and olive oil) on a woven cotton fabric. Distribution of oily soil on fabrics was determined for three different treatments (unwashed, washed with detergent without lipase, and washed with detergent plus lipase). Osmium tetroxide was used to label lipid soil for analysis in the scanning electron microscope. Both longitudinal and cross-sectional backscattered electron images for unwashed samples showed that soil was present on surfaces of the cotton fibers and in interfiber spaces of the yarn bundle. Lard soiled samples had large deposits on the fabric surfaces, while artificial sebum and olive oil appeared more uniformly distributed throughout the textile. Oil was deposited in the interfiber capillaries of the yarn bundle and in the crenulation, secondary walls, and lumen of the fibers. Energy dispersive X-ray microanalysis was used to determine relative concentrations of oil at selected morphological locations within the fiber structure and at the fiber surface. Soil distributions within the fibrous structures differed with type of soil and laundry treatment. Backscattered electron images dramatically demonstrated the effect of lipase on cleaning. After washing with detergent plus lipase, yarn surfaces had much less residual soil; residual soil that remained was in the irregularities of the cotton fiber surfaces. Concentrations of oil in the secondary walls, crenulations, lumen, and the fiber surfaces were lower after lipase treatment for all three soils. While washing with detergent removed soil from the yarn and fiber surfaces and the crenulation of the cotton fiber, only the samples washed with detergent plus lipase had lower concentrations of soils within the secondary wall and lumen of the cotton fibers. Fabrics soiled with olive oil and washed with detergent plus lipase had the lowest concentrations of residual soil across the textile structure; the residual soil observed was mainly in the irregularities on the fiber surfaces.     

Distribution of carboxyl groups in carboxymethylated cotton fibers

Cotton cellulose was partially carboxymethylated by a one‐bath method using monochloroacetic acid and sodium hydroxide. A method was developed to study the extent of the carboxymethylation of cellulose within the cotton fibers using scanning electron microscopy (SEM) and energy‐dispersive X‐ray analysis (EDX). Uranyl nitrate was used as a stain. Scanning electron photomicrographs revealed that the carboxymethylation of cellulose occurred throughout the cotton fiber cross section. However, the X‐ray microanalysis data indicated a variation in the extent of the reaction among the morphological regions that have different chemical accessibility. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 203–207, 1999     

Graft copolymerization of vinyl monomers on modified cottons. VI. Vinyl graft copolymerization initiated by manganese (IV)

The ability of potassium permanganate in the presence of different acids to induce grafting of methyl methacrylate and acrylonitrile onto sodium hydroxide-treated cotton, partially carboxymethylated cotton, partially cyanoethylated cotton, and partially acetylated cotton was investigated. The copolymerization reaction was carried out under a variety of conditions. The graft yields are greatly enhanced by increasing concentration of monomer, reaction time, and temperature. The opposite holds true for initiator at higher concentrations. The effectiveness of the acids was: nitric acid > sulfuric acid > perchloric acid > hydrochloric acid. The change in the physical and/or chemical structure of cellulose by its modification via etherification reaction or esterification reaction had a significant effect on the susceptibility of cellulose toward grafting. While partial carboxymethylation or partial cyanoethylation of cellulose prior to grafting increased the graft yield, partial acetylation caused a decrease.     

Detergency of used motor oil from cotton and polyester fabrics

A study was conducted to identity factors contributing to the difficult removal of used motor oil from textile materials by detergency. Infrared spectroscopy and gel permeation chromatography of used motor oil showed that the oil was a saturated aliphatic hydrocarbon with molecular weight around 950. X-ray analysis revealed that particulates present in the used motor oil contained S, Mg, Al, Si, K, Ca, Fe, Ni, Cu, and Zn. Used motor oil was distributed throughout the cotton fibers with similar concentration of oil in the lumen, secondary wall, and surface crenulation. Higher relative concentrations of used motor oil were observed in the secondary wall of the fiber than has been reported for human sebum. No oil was found in the interior of polyester fibers although high concentrations of oil were detected in the interfiber spaces and on the fiber surfaces of polyester fibers. Dispersant additives of motor oil are though to enhance penetration into the cotton structure and wicking over the polyester fibers, making the nonpolar used motor oil very difficult to remove by detergency.     

Enhancing the reactivity and strength of cotton fibers

Both sodium hydroxide solution of mercerizing strength and anhydrous methylamine are suitable pretreatments for enhancing the reactivity of cotton cellulose. Favorable results are achieved by maintaining the fiber material in the never-dried state after the swelling treatment. Extraction by organic solvents is to be preferred over water-washing in order to remove the swelling agent. When cotton is swollen with either aqueous sodium hydroxide or anhydrous methylamine and then washed and dried, its crystallinity, as determined by X-ray diffraction is not lowered as much as it is if it is acetylated to an acetyl content of about 9% before drying. The greatest modifications of the crystal structure of cotton were found on methylamine treatment followed by chloroform and pyridine washing and acetylation in the never-dried state (MeCP product), as well as by alcoholic mercerization followed by ethanol and pyridine washing and acetylation in the never-dried state (AMEP). As determined by moisture regains, no significant differences are apparent between the accessibility of samples of low acetyl content (ca. 9%) prepared by either the AMEP or by the MeCP treatment. The DTA curves of methylamine-treated cotton with an acetyl content close to that of commercial diacetate and the commercial product are dissimilar. It can be concluded from the DTA curve of the deacetylated product prepared from this MeCP sample that it has a highly disordered structure. The tensile properties of the acetylated products of low acetyl content are considerably improved if acetylation is preceded by mercerization with subsequent solvent exchange, and less so if it is preceded by methylamine followed by solvent exchange. Incorporation of acetyl groups significantly enhances the breaking strength and extensibility of mercerized solvent-washed materials.     

Chemical factors affecting soiling and soil release from cotton-containing durable press fabric. VI. Effect of introduction of carboxymethyl groups in the cotton component of polyester/cotton blend

Partial carboxymethylation of the cotton component of polyester/cotton blend prior to durable press finishing with dimethyloldihydroxyethylene urea in presence of MgCl₂·6H₂O was carried out under different conditions to control the carboxyl content as well as alteration of the blend components accompanying the chemical modification. The susceptibility of these modified blend samples before and after crosslinking to aqueous and nonaqueous oily soiling and their ability to release the soil was examined. The general indications are that introduction of carboxymethyl groups in the molecular structure of the cotton component of the blend imparts soil release characteristics of the blend provided that (a) the condition of partial carboxymethylation is not accompanied by profound changes in neither the microstructure of the cotton component nor in the polyester content of the blend and (b) the carboxymethyl content should not be so high. It is proposed that the anionic nature of the modified cotton component of the blend during washing helps in repelling the negatively charged soil particles from the blend surface. In addition, a reduction in the interfacial tension at the soil–water interface assists in rolling up the soil and subsequent removal. This can be turned to the opposite if the electrostatic repulsion is masked through creation of soft swollen environment by significantly increasing the carboxymethyl content, decreasing the polyester content, and/or increasing the swellability of cotton component of the blend.     

Influence of carboxymethylation on the surface physical–chemical properties of glucuronoxylan and arabinoxylan films

Xylans were carboxymethylated in order to increase their anionic nature and thus tune their surface free energy (SFE) and hydrophilicity, which are of crucial importance in the majority of special applications. Fourier transform infrared spectroscopy and polyelectrolyte titration results confirmed the successful carboxymethylation of the xylan samples. The main aim of this study was to investigate the influences of carboxymethylation of glucuronoxylan and arabinoxylans on the surface physical and chemical properties of the films made from them. Films were prepared by the casting method, and their surface morphologies were analyzed by atomic force microscopy. The surface chemical compositions of the films were investigated using X‐ray photoelectron spectroscopy, and their influences on SFE, i.e., Lifshitz–van der Waals and electron donor and acceptor contributions, were determined using goniometry. The introduction of ～2 mmol/g of carboxyl groups into the glucuronoxylan or arabinoxylan molecular structures had a significant influence on the chemical and physical surface properties of the prepared films. Higher amounts of the carboxyl group present on the films' surfaces and higher surface roughness contributed to a significant increase (by 270%) in the electron donor component of SFE and to 40% improvements in the hydrophilicities of the films' surfaces. POLYM. ENG. SCI., 55:2706–2713, 2015. © 2015 Society of Plastics Engineers     

Microscopy Study of Distribution of Laundry Fabric Softener on Cotton Fabric

Distribution of fabric softeners on cotton terry cloth was studied using scanning electron microscopy and energy dispersive X-ray analysis. The unsaturated groups in the quaternary fabric softeners were tagged with osmium tetroxide to provide contrast in the microscopy. Longitudinal specimens showed the fabric softeners distributed over the cotton fiber surfaces with more in the crenulation of the fiber. Cross sectional specimens revealed that the fabric softener was distributed throughout the cotton fibers with higher concentrations of fabric softener observed in the lumen and crenulation than in the secondary wall and non-crenulated fiber surface. This distribution of fabric softener is consistent with deposition on both external fiber surfaces and internal fibril surfaces. The deposition and final surface coverage is strongly dependent on the pH value of the washing medium. Repeated treatment cycles with fabric softener using a higher pH washing media resulted in higher concentrations of fabric softener on and within the cotton fibers. Neutral or lower pH washing media resulted in a somewhat constant concentration of fabric softener on and with cotton fibers with increased number of treatment cycles. Differences in perception of softness of the treated fabrics are not explained by differences in distribution of the fabric softener; it appear that there is an optimum amount of softener to achieve the desired sensory response and that further deposition build-up does not increase perception of softness.

Identification and quantification of glycerolipids in cotton fibers: Reconciliation with metabolic pathway predictions from DNA databases

The lipid profiles of cotton fiber cells were determined from total lipid extracts of elongating and maturing cotton fiber cells to see whether the membrane lipid composition changed during the phases of rapid cell elongation or secondary cell wall thickening. Total FA content was highest or increased during elongation and was lower or decreased thereafter, likely reflecting the assembly of the expanding cell membranes during elongation and the shift to membrane maintenance (and increase in secondary cell wall content) in maturing fibers. Analysis of lipid extracts by electrospray ionization and tandem MS (ESI-MS/MS) revealed that in elongating fiber cells (7–10 d post-anthesis), the polar lipids—PC, PE, PI, PA, phosphatidylglycerol, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, and phosphatidyl-glycerol—were most abundant. These same glycerolipids were found in similar proportions in maturing fiber cells (21 dpa). Detailed molecular species profiles were determined by ESI-MS/MS for all glycerolipid classes, and ESI-MS/MS results were consistent with lipid profiles determined by HPLC and ELSD. The predominant molecular species of PC, PE, PI, and PA was 34∶3 (16∶0, 18∶3), but 36∶6 (18∶3, 18∶3) also was prevalent. Total FA analysis of cotton lipids confirmed that indeed linolenic (18∶3) and palmitic (16∶0) acids were the most abundant FA in these cell types. Bioinformatics data were mined from cotton fiber expressed sequence tag databases in an attempt to reconcile expression of lipid metabolic enzymes with lipid metabolite data. Together, these data form a foundation for future studies of the functional contribution of lipid metabolism to the development of this unusual and economically important cell type.     

Lipid distribution on cotton textiles in relation to washing with cellulase

Enzymes are used widely as effective additives to laundry detergents for improved detergency on soiled fabric. They have potential for cleaning of “dingy” soils in addition to the stain removal benefits. Cellulases contribute to the overall whiteness of cotton-containing textiles when worn and washed several times, meaning that their cleaning is not associated solely with the regions characterized by high amounts of fatty material, e.g., collars/cuffs. The focus of this research was to study further the performance of cellulases for whiteness maintenance of cotton textiles. Cotton garments soiled by multiple wearings and washed using a cellulase treatment were evaluated using scanning electron microscopy and X-ray microanalysis. Washing with cellulase significantly reduced residual soil concentrations at all morphological locations on the cotton fibers for each set of matched garments. The relative concentrations of residual soil on the fabrics agreed well with the color differences measured at 440 nm. Cellulase affected removal of oily soil from within the cotton fiber secondary wall, resulting in residual oil concentrations similar to those at morphological locations that were more accessible for detergency such as the fiber surface and crenulations. Since cellulase hydrolyzes cellulose, it was expected that the effect would be within the structure of the fiber, i.e., secondary wall. The cellulase effect on redeposition garments was similar to garments worn and washed. As with lipase, the enhanced removal of soil from the interior bulk structure of the cotton fiber with use of cellulase is unique, since most other detergent components have higher functionality at fabric, yarn, and fiber surfaces. We think that cellulase is functioning by hydrolyzing cellulose from the internal surfaces of fibrils within the secondary wall, opening up the pore structure for enhanced detergency and forming a new surface with each washing.     

羧甲基甲壳胺纤维对铜离子的吸附性能

为了提高甲壳胺纤维对重金属离子的吸附性能,用氯乙酸对纤维进行改性处理,在纤维的结构中引入羧甲基团后使纤维同时具有能结合重金属离子的胺基和羧酸基团。研究了改性后纤维在不同的改性程度、添加量、时间、温度、pH值等条件下对铜离子的吸附性能。结果表明:羧甲基化改性后的甲壳胺纤维对铜离子有很好的吸附性能。在同样的条件下,未改性的纤维对铜离子的吸附值为41.3mg/g,而改性后的纤维为79.4mg/g。经过羧甲基化改性的甲壳胺纤维对铜离子的饱和吸附容量可以达到148.1mg/g。     

Oxidative susceptibility of partially carboxymethylated cotton to gamma radiation

Partially carboxymethylated cotton with a DS of about 0.05–0.15 retains its original fibrous nature and exhibits a number of potentially valuable properties, such as a crisp hand with a slightly starched feel, increased moisture regain, water absorbancy, water permeability, changed dyeing characteristics, increased resistance to soiling from aqueous dispersions, and greater ease of soil removal.^5–8 Furthermore, detailed studies have been reported on the behavior of partially carboxymethylated cotton toward oxidation and hydrolysis,⁹ vinyl graft polymerization,¹⁰ transfer printing,^11,12 cross-linking,¹³ and thermal treatments.¹⁴     

Surface characterization and adsorption abilities of cellulose fibers

The adsorption abilites of cotton cellulose fibers are very often modified by alkaline treatments in form of alkaline purification or mercerization using high concentration of NaOH. We tried to determine the correlation between morphological modifications and the adsorption abilities of cotton fibers using several methods: the analysis of microscope images of fibers by image processing and the analysis of the electrokinetic surface properties which express the adsorption behavior of fibers. The longitudinal images and cross-sections of native and modified cotton fibers were analyzed and the parameters: form factor, wall thickness, cross-section area, fiber diameter, lumen area were calculated using image processing. The adsorption behavior of native and NaOH modified polymers was investigated by the determination of electrokinetic properties. The zeta potential (ζ) was calculated from streaming potential measurements as a function of pH and surfactant concentration in the liquid phase. The results indicate that only a correct combination between the morphological modifications and electrokinetic behavior of fibers leads to a desirable adsorption mechanism which causes a specific adsorption of components of the liquid phase.     

Sodium cellulose formation by activation process

The formation of sodium cellulose is the first reaction step in some large scale derivatization process of cellulose, e.g., xantation or carboxymethylation, as well as in the mercerization of cotton. It was found that the sodium cellulose formation depends on some activators present in the steeping lye, as well as on the press ratio, steeping temperature, and steeping ley concentration. IR data and X-ray scattering showed that the initial native cellulose was converted into an unoriented cellulose II in the lower concentration of steeping ley with presence of urea, thiourea, and sodium aluminate or zincate as activators. The sodium cellulose formed with activators was more reactive to xanthation than the cellulose from unactivated process.     

新型挂膜纤维材料的研究

采用组合填料并选用合适的挂膜纤维,对城市生活污水及实验室自配原水进行处理。结果表明:处理后出水稳定,化学需氧量CODcr去除率高,平均CODcr去除率在75%￣80%;改善填料的亲水性能有利于提高出水水质,选用的聚丙烯腈纤维和聚乙烯醇纤维在同等处理条件下的处理效率分别高出参照纤维聚丙烯6.9%和2.9%;增大纤维的比表面积,CODcr的去除率提高,但比表面积的提高应以保证纤维的分散性为前提。     

Effect of carboxymethylation on the absorption and chelating properties of chitosan fibers

Chitosan fibers were treated with chloroacetic acid to prepare partially substituted carboxymethyl chitosan fibers. Fibers with different levels of carboxymethylation were prepared by controlling the ratio between the fiber and the amount of chloroacetic acid. The absorption properties of the modified fibers for Cu(II) ions were studied at different concentrations, temperature, time, and pH. Results showed that the carboxymethylated chitosan fibers were more effective than the original chitosan fibers in removing Cu(II) ions from aqueous solutions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3110–3115, 2006     

Hot Alkali Refining of Cellulosic Pulps in the Presence of Sodium Sulfide

Cotton linter pulp and paper pulp were subjected to hot refining with potassium and sodium hydroxide in the presence of sodium sulfide at concentrations of 5% and 20%. The resulting changes in their chemical, physical, and submicroscopic properties as well as their mercerization depth were studied. The addition of sodium sulfide during hot sodium or potassium hydroxide refining of the pulps resulted in a small increase in α-cellulose content of the cotton linters. Remarkable increase was observed in the case of the paper pulp as well as in the resulting decrystallization, and it increased the heterogeneity of the macromolecular structure of both pulps. This led to an increase in the swelling ability of the fibers as revealed from the results of water retention value (WRV), liquor retention value (LRV), and sodium hydroxide retention value (NaOH RV). The addition of sodium sulfide to sodium or potassium hydroxide during hot refining of the cotton linters or to sodium hydroxide during refining of the paper pulp led to the reduction in the degree of polymerization and to improvement in the reactivity towards xanthation. This was in contrast to the results of the alkali refining of the paper pulp with a mixture of potassium hydroxide-sodium sulfide in which the degree of polymerization was increased and the reactivity towards xanthation was decreased. The mercerization depth of the hot refined pulps was also investigated using FUR 1650 spectrophotometer absorption method. The cotton linters refined with a mixture of 5% sodium hydroxide-sodium sulfide possessed a higher degree of chemical purity and a good open and accessible fine structure and at the same time were characterized with a higher degree of polymerization suitable for use as a starting refined pulp for the manufacture of paper documents.     

Reaction of formaldehyde with cellulose in the presence of sulfuric acid

The extent and rate of reaction between cotton yarn before and after slack mercerization and slack mercerization followed by stretching and formaldehyde, in the presence of various amounts of sulfuric acid (5–60% by weight) were studied. Beyond a concentration of 45% sulfuric acid, the reaction takes place very rapidly, and an explanation is put forward in terms of the extent of swelling of the fiber in sulfuric acid solutions. The reaction was also studied in the presence of glycerin, when the combined formaldehyde value is shown to decrease with an increasing concentration of glycerin.