Flame retardant finishing of cotton fabric based on synergistic compounds containing boron and nitrogen

Boric acid and compound containing nitrogen, 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-HTAC) were used to finish cotton fabric. The flame retardant properties of the finished cotton fabrics and the synergetic effects of boron and nitrogen elements were investigated and evaluated by limited oxygen index (LOI) method. The mechanism of cross-linking reaction among cotton fiber, Tri-HTAC, and boric acid was discussed by FTIR and element analysis. The thermal stability and surface morphology of the finished cotton fabrics were investigated by thermogravimetric analysis (TGA) and scanning electron microscope (SEM), respectively. The finishing system of the mixture containing boron and nitrogen showed excellent synergistic flame retardancy for cotton fabric. The cotton fabric finished with mixture system had excellent flame retardancy. The LOI value of the treated cotton fabric increased over 27.5. Tri-HTAC could form covalent bonds with cellulose fiber and boric acid. The flame retardant cotton fabric showed a slight decrease in tensile strength and whiteness. The surface morphology of flame retardant cotton fiber was smooth.     

Cellulose esters from waste cotton fabric via conventional and microwave heating

The esterification of cellulose from waste cotton fabric in a N,N-dimethylacetamide/lithium chloride solvent system was carried out using different types of fatty acid chloride including butyryl chloride, capryloyl chloride, and lauroyl chloride as esterifying agents, and N,N-dimethyl 1-4-aminopyridine as a catalyst under conventional and microwave activation. Microwave esterification was performed under 2.45 GHz with power varying from 90 to 450 W. The optimum conditions for esterification of cotton cellulose with various esterifying agents were investigated in terms of reaction time and temperature to attain appropriate %weight increase and degree of substitution of esterified-cellulose. The degree of substitution, functional group and chemical structure, and thermal stability of cellulose ester powder were characterized by ¹H NMR, FTIR, and TGA/SDTA analysis. Morphologies, crystallinity, and solubility of modified cellulose by two different heating methods were compared.     

Preparation and characterization of durable antibacterial cellulose biomaterials modified with triazine derivatives

Cellulose fabric was chemically modified with the triazine derivatives containing the multi-cationic benzyl groups. The novel durable antibacterial cellulose biomaterial containing the multi-cationic benzyl groups was prepared. The chemical structure and thermal property of the antibacterial cellulose biomaterial were investigated with FT-IR spectra, nitrogen content analysis, and differential scanning calorimetry (DSC). The results show that the thermal stability of the novel antibacterial cellulose was slightly decreased. Physical properties of the novel antibacterial cellulose had not significant change. The novel antibacterial cellulose imparted excellent durable antibacterial properties.     

Cutinase promotes dry esterification of cotton cellulose

Cutinase from Thermobifida fusca was used to esterify the hydroxyl groups of cellulose with the fatty acids from triolein. Cutinase and triolein were pre‐adsorbed on cotton and the reaction proceeded in a dry state during 48 h at 35°C. The cutinase‐catalyzed esterification of the surface of cotton fabric resulted in the linkage of the oleate groups to the glycoside units of cotton cellulose. The superficial modification was confirmed by performing ATR‐FTIR on treated cotton samples and by MALDI‐TOF analysis of the liquors from the treatment of the esterified cotton with a crude cellulase mixture. Modified cotton fabric also showed a significant increase of hydrophobicity. This work proposes a novel bio‐based approach to obtain hydrophobic cotton. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:60–65, 2016     

Antimicrobial and chemical detoxifying functions of cotton fabrics containing different benzophenone derivatives

Several benzophenone chromophoric groups were incorporated onto cotton fabrics by using 4-hydroxybenzophenone, 4,4′-dihydroxybenzophenone, 4-chloro-4′-hydroxybenzophenone, and 4-benzoylbenzoic acid as reagents. The fabric treatment was conducted by a pad-dry-cure method, and the benzophenone chromophoric group incorporated cotton fabrics were characterized and confirmed by FTIR. Tensile strengths of benzophenone chromophoric groups modified cotton fabrics were also measured. 4-Hydroxybenzophenone treated cotton fabric showed the most powerful antibacterial activity among all samples, and 4-benzoylbenzoic acid treated cotton fabric demonstrated pesticide degradation ability, under UV irradiation.     

Nonformaldehyde durable press finishing of cotton fabrics using the combination of maleic acid and sodium hypophosphite

Polycarboxylic acids have been used as nonformaldehyde crosslinking agents for cotton with sodium hypophosphite (NaH₂PO₂) as the catalyst to replace the formaldehyde-based dimethyloldihydroxyethleneurea (DMDHEU). Maleic acid (MA), an α, β-unsaturated bifunctional carboxylic acid, can esterify cotton but is not able to form crosslinking between two cellulose molecules by itself. In this research, we discovered that the wrinkle resistance of the cotton fabric treated with MA and NaH₂PO₂ was significantly increased and phosphorus was bound to cotton when the treated fabric was exposed to temperatures higher than that required for esterification of cotton by MA. Elevation of the fabric wrinkle resistance and increase in quantity of the phosphorus bound to cotton had similar dependency on curing temperature, on MA concentration, and on NaH₂PO₂ concentration. All the data support the hypothesis that H-P-(residual of NaH₂PO₂) added to >CC< of the MA already bound to cotton by esterification, thus forming a new crosslink between two cotton cellulose molecules. The cotton fabrics treated by MA/NaH₂PO₂ showed fabric wrinkle resistance similar to that treated with DMDHEU, but the breaking strength and tearing strength of the MA-treated cotton fabrics were significantly improved.     

Thermal stability, flame retardancy and mechanical properties of cotton fabrics treated with inorganic coatings synthesized through sol-gel processes

Cotton was sol-gel treated employing several metal alkoxide precursors (namely, tetraethylortho-silicate, -titanate, -zirconate and aluminium isopropylate) in order to get inorganic phases able to improve the thermal stability and flame retardancy of the fabric, without changing its mechanical features. Indeed, after the sol-gel treatment the fibre/fabric surface was morphologically modified: a homogeneous and compact film located in the fibre interstices (warp and weft) and partially covering their walls was observed for all the systems investigated. These coatings turned out to be responsible of an overall enhancement of the thermal and fire stability of the fabrics preserving, at the same time, the original mechanical properties of the neat cotton in terms of tensile strength and deformation. In addition, such inorganic coatings increased the abrasion resistance of the cotton in a remarkable way.     

Microwave curing for producing cotton fabrics with easy care and antibacterial properties

A new microwave curing system was used to affect crosslinking of cotton fabric with nonformaldehyde finishes, namely, glyoxal, glutaraldehyde and 1,2,3,4 butanetetracarboxylic acid (BTCA). Water soluble chitosan was incorporated in the finishing bath in order to impart antibacterial activity to the fabric in addition to the ease of care characteristics. Glyoxal proved to be the best finish and, hence, it was studied along with the chitosan under a variety of conditions including chitosan concentrations, power and time of microwave curing. Besides the crease recovery and strength properties of the finished fabrics, the latter were also monitored for N%, antibacterial activity and characterized using scanning electron microscope (SEM) and FTIR spectra when compared. With conventional curing system, the microwave curing system was found advantageous in production of cotton fabrics with easy care antibacterial properties without high losses in strength properties.     

Enhancing antimicrobial properties of dyed and finished cotton fabrics

1,2,3-Benzothiazole-7-thiocarboxylic acid-S-methylester (commercially known as Actigard^® AM-87) was utilized to impart cotton fabric durable antimicrobial properties. Finishing treatment was carried out under a variety of conditions. The latter were included, effect of pH, concentration of antibacterial agents, curing temperature and curing time. The effect of fabric construction, mercerization, and dyeing with different dyestuff were also investigated. The study was also extended to investigate the technical feasibility of combining antimicrobial finishing treatment in question with other finishing treatment generally carried out on cotton fabric, like soft finishing and crease recovery finishing. The treated fabrics were monitored for antimicrobial properties before and after washing. The treated fabrics were also evaluated for the physio-mechanical properties like fabric tensile strength, elongation at break (or bursting strength for knitted fabric), wettability, crease recovery angle, whiteness index and roughness. Results obtained show that, the most appropriate conditions for treatment cotton fabric with Actigard^® are: padding the cotton fabric in aqueous solution containing 6% Actigard^® at pH 5 (adjusted using formic acid) then squeezed to wet pick up of 100%, dried at 80 °C for 5 min then cured at 100 °C for 150 s. The untreated cotton fabric did not show any antimicrobial activity towards Staphylococcus aureus or Escherichia coli. Treatment of cotton fabric with Actigard^® improves its antimicrobial properties towards S. aureus or E. coli. It is also observed that, treatment of cotton fabric with Actigard^® marginally decreases fabric tensile strength, elongation at break, roughness and WI, whereas; both wettability and crease recovery angle remain practically intact. This was observed whether the fabric was pre-mercerized or not.     

Surface modification of cellulose with triazine derivative to improve printability with reactive dyes

Chemical modification of cellulose with triazine derivative, 2,4,6-tri-[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-HTAC), was investigated. Micro-FT-IR and nitrogen element analysis were applied to characterize molecular structure of the modified cellulose. The printing properties of the modified cellulose fabric with Tri-HTAC were discussed. Tri-HTAC was able to form covalent bonds with cellulose fibers. The apparent color strength of printed samples with three reactive dyes on the modified cellulose was higher than the corresponding color yields on the unmodified cellulose fabric. Compared with unmodified cellulose, the increases of the color yield were about 6–13%. The fixation rate was accelerated by the modification with Tri-HTAC. The wet rubbing and washing fastnesses of the printed cellulose fabrics modified with Tri-HTAC were better than those of the printed unmodified cellulose fabric. The modified cellulose with Tri-HTAC imparted good printing properties.     

Effects of Thermobifida fusca cutinase-carbohydrate-binding module fusion proteins on cotton bioscouring

Previously, we presented a novel approach for increasing Thermobifida fusca cutinase adsorption on cotton fibers by fusing cutinase with a carbohydrate-binding module (CBM). A preliminary study showed that two fusion proteins, namely cutinase-CBM_Cel6A and cutinase-CBM_CenA, with similar stabilities and catalytic properties, had potential applications in bioscouring. In the present study, an indepth analysis of both cutinase-CBMs in bioscouring was explored. Effects of cutinase-CBMs on cotton bioscouring were investigated by characterizing the chemical and physical surface changes in enzyme-treated cotton fabrics. Gas chromatography/mass spectrometry was used to analyze the degradation of the cotton fabric cuticle; Fourier transform infrared microspectroscopy was used to study changes in the chemical composition of the cotton fabric epidermal layer; and scanning electron microscopy was used to monitor minor changes in the morphology of the fiber surface. Our results indicated that cutinase-CBMs in combination with pectinase had a greater effect on cotton fabric than did cutinase. Following scouring with cutinase-CBMs and pectinase, the performance of cotton fabric in terms of its wettability and dyeability was similar to that following alkali scouring. Our study provides a foundation for the further application of cutinase-CBM to bioscouring.     

An eco-friendly – novel approach for attaining wrinkle – free/soft-hand cotton fabric

A novel approach for upgrading both the wrinkle free and softness properties of cotton fabrics without adversely affecting their strength properties using an eco-friendly finishing regimes was investigated. Factors affecting the performance properties of the finished substrate such as pre-treatment, i.e., carboxymethylation (CMC) or ionic-crosslinking, post-treatment with amino functional silicone softener and its concentration, degree of carboxymethylation as well as thermofixation conditions were studied. The obtained results revealed that post-treatment with the amino based silicone micro emulsion (SiE) up to 30 g/L at pH 4 to a wet pickup of 100% followed by drying at 100 °C for 5 min and curing at 170 °C for 3 min results in a remarkable improvement in fabric resiliency (expressed as dry and wet wrinkle recovery angles), as well as in softness degree, without seriously affecting its retained strength. Improvement extent of the aforementioned properties is governed by the nature of the pre-treatment steps. Fixation of the amino-functional silicone softener onto/or within the modified cellulose structure is accompanied by a formation of semi-inter and/or intra-penetrated network (semi-IPN) thereby enhancing both the extent of crosslinking and networking as well as providing very high softness. FTIR analysis proved the formation of Si–O–Si–cellulose complex. Scanning electron micrograph shows that cotton, CMC and ionic crosslinked cotton fabrics treated with SiE shows higher surface smoothness and considerable reduction in protruding loose fibers, ditches and grooves compared with the untreated one.     

Transglutaminase mediated grafting of silk proteins onto wool fabrics leading to improved physical and mechanical properties

Transglutaminases have the ability to incorporate primary amines and to graft peptides (containing glutamine or lysine residues) into proteins. These properties enable transglutaminases to be used in the grafting of a range of compounds including peptides and/or proteins onto wool fibres, altering their functionality. In this paper we investigated the transglutaminase mediated grafting of silk proteins into wool and its effect on wool properties. A commercial hydrolysed silk preparation was compared with silk sericin. The silk sericin protein was labelled with a fluorescent probe which was used to demonstrate the efficiency of the TGase grafting of such proteins into wool fibres. The TGase mediated grafting of these proteins led to a significant effect on the properties of wool yarn and fabric, resulting in increased bursting strength, as well as reduced levels of felting shrinkage and improved fabric softness. Also observed was an accumulation of deposits on the surface of the treated wool fibres when monitored by SEM and alterations in the thermal behaviour of the modified fibres, in particular for mTGase/sericin treated fibres which, with the confocal studies, corroborate the physical changes observed on the treated wool fabric.     

Gamma-radiation induced changes in the physical and chemical properties of lignocellulose

gamma-radiation induced effects on the physical and chemical properties of natural lignocellulose (jute) polymer were investigated. Samples were irradiated to required total doses at a particular dose rate. The changes in the parameters such as the tensile strength, elongation at break, and work done at rupture for the lignocellulose samples on irradiation with the gamma-rays from a cobalt-60 source were measured. The mechanical properties were found to have nonlinear relations with the radiation doses. The chemical stability of irradiated fibers was found to degrade progressively with the increase of radiation dose. Additionally, other chemical changes of the samples due to exposure to high-energy radiation were also investigated using fluorescence and infrared spectroscopic analysis. Differential scanning calorimetry and thermogravimetric studies showed a significant reduction in thermal stability. The wide-angle X-ray diffraction study showed that structural changes of cellulose appeared due to the radiation-induced chemical reaction of lignocellulose.     

Mode of action of cellulases on dyed cotton with a reactive dye

Cotton woven fabrics which were previously dyed with a reactive dye were treated with a commercial cellulase preparation. Dyeing with a reactive dye for cotton apparently inhibited the weight loss activity and saccharification activity of cellulase. In addition, dyed cotton was treated with highly purified cellulases which were exo-type cellulases (Cellobiohydrolase I (CBH I) and Cellobiohydrolase II (CBH II)) and endo-type cellulase (Endoglucanase II (EG II)). Exo-type cellulases were inhibited more than endo-type cellulase by dyeing in the case of saccharification activity. CBH I was severely inhibited by dyeing as compared with CBH II or EG II from the viewpoint of morphological changes in the fiber surface. Dyes on the cellulose substrates severely influenced CBH I in spite of the rare modification, because CBH I hydrolyzed cellulose with true-processive action. The change in the activity of each cellulase component on dyed cotton can affect the synergistic action of cellulases.     

Action of purified Trichoderma reesei cellulases on cotton fibers and yarn

In this work the possibility and potential of treating cotton fibers and yarns instead of fabrics with monocomponent cellulases was investigated. Different pretreatments on fibers were performed and tested in order to improve the accessibility of cotton to enzymatic modification. The enzymatic treatments were evaluated microscopically and by analysing the effects of treated fibers on spinnability, yarn evenness, tenacity and pilling. The accessibility of the cotton fibers for cellulases could be increased by different pretreatments. Steaming of fibers prior to enzymatic treatment was found to be an efficient way to increase hydrolysis levels. Cellulase treatments of carded yarns resulted in modification of yarn properties. Decrease in yarn hairiness was observed and the knitted fabric made of the treated yarn showed a lowered tendency towards pilling. In all cases endoglucanase activity rather than cellobiohydrolase activity was responsible for these modifications.     

Functional finishing of health care cotton for enhanced efficiency of antibacterial activity by chitosan and herbal nanocomposites

To enhance the efficiency of biological, chemical and physical properties like antibacterial activity, wash durability, air-permeability and biocompatibility of cotton fabric finished with chitosan and herbal nanocomposites. Extracts of Cassia angustifolia and Tamarindus indica with chitosan solution was bulk finished on 40s cotton fabrics. To increase the functional properties, chitosan and herbal extract nanocomposites were finished on to another set of fabrics (nanocomposite finishing). Different functional properties were carried out for both the sets of fabrics and comparatively analyzed. Antibacterial activity, physical properties and biocompatible properties of the finished fabric were determined. Antibacterial activity of nanocomposite finished fabrics showed inhibitory zones of 33 mm for E. coli and 31.6 mm for S. aureus. Nanocomposite finished fabrics showed good durable properties and physical properties than bulk finished fabrics. The study concludes that, nanocomposites could provide better functional properties than the bulk finished fabrics. The nano sized particles in the composites was considered significant for its functional applications in hospital based fabrics to prevent the transmission of nosocomial infections.     

Triazinyl porphyrin-based photoactive cotton fabrics: preparation, characterization, and antibacterial activity

In the present work, we report on the synthesis of cellulose cotton fibers bearing different types of photosensitizers with the aim to prepare new efficient polymeric materials for antimicrobial applications. Anionic, neutral, and cationic amino porphyrins have been covalently grafted on cotton fabric, without previous chemical modification of the cellulosic support, using a 1,3,5-triazine derivative as the linker. The obtained porphyrin-grafted cotton fabrics were characterized by infrared (ATR-FTIR), diffuse reflectance UV-vis (DRUV) spectroscopies, and thermogravimetric analysis (TGA) to confirm the triazine linkage. Antimicrobial activity of porphyrin-cellulose materials was tested under visible light irradiation against Staphylococcus aureus and Escherichia coli . The results showed excellent activity on the Gram-positive bacterium, showing structure-activity relationship, although no photodamage of the Gram-negative microorganism was recorded. A mechanism of bacterial inactivation by photosensitive surfaces is proposed.     

Biopreparation of cotton fabric with enzymes produced by solid-state fermentation

Fungal enzyme preparations from Phanerochaete chrysosporium, Aspergillus oryzae, Aspergillus giganteus and Trichoderma virens, produced by solid-state fermentation (SSF) on cotton seed-coat fragment waste as substrate and enzyme inducer were investigated in biopreparation of cotton fabric. Cotton seed-coat fragment is rich in lignin, cellulose and hemicelluloses, therefore enzyme complexes produced by target fungi on such a substrate can be used effectively to degrade impurities in cotton fabrics during biopreparation. Activities of extracellular hydrolytic and ligninolytic enzymes were determined from the SSF extract materials. The potential of the hydrolytic and accompanying oxidative enzymes in the whole SSF cultures was exploited in degradation of seed-coat fragments and other coloring materials of greige cotton fabric. Enzyme assays indicated that many extracellular enzymes have been produced under these conditions including both hydrolytic and oxidative enzymes. A. oryzae NRRL 3485 produced significantly higher amounts of both hydrolytic and oxidative enzymes than other tested fungi. Best results in removal of seed-coat fragments from cotton fabric were obtained by P. chrysosporium NCAIM (=ATCC 34541), P. chrysosporium VKM F-1767 and A. oryzae NRRL 3485 SSF enzyme complexes.     

Cellulase finishing of woven, cotton fabrics in jet and winch machines

Some authors have reported that as the applied agitation rate increases, the apparent activity of the endoglucanases from Trichoderma reesei towards cotton cellulose increases more markedly than does the apparent activity of the cellobiohydrolases. This suggests that the quality of cellulase finishing effects on cellulosic textiles may be machine-type dependent. The present work using total crude, endoglucanase-rich and cellobiohydrolase-rich cellulases from T. reesei confirmed that the final properties of woven, cotton fabrics treated under realistic processing conditions in a jet machine, were measurably and perceivably different from those of the same fabrics, treated using the same processing conditions of temperature, time, pH, enzyme concentration and fabric to liquor ratio, but in a winch machine. The results are interpreted in terms of the effects of agitation rate on the adsorption–desorption behaviour of the T. reesei endoglucanases and cellobiohydrolases.