Alkaline dissolution monitoring of sea–island type polyester microfibre fabrics by a cationic dye staining method

The alkaline dissolution behaviour of sea–island type polyester microfibres were successfully monitored using a cationic dye staining method. Weight reduction behaviour of the alkali-treated microfibre fabrics and the treated fabrics stained with cationic dye were investigated in a comparative manner. The termination of dissolution monitored by both methods was also confirmed by scanning electron microscopy.     

Methyl methacrylate‐assisted dyeing of polyamide microfibre

Polyamide microfibres were dyed using disperse dye in the presence and absence of methyl methacrylate. The dye uptake and colour strength in the presence of methyl methacrylate were substantially higher than in its absence. Scanning electron microscope analysis showed that there was a dye layer on the microfibre surface formed by methyl methacrylate adsorption after dyeing. Differential scanning calorimetry measurement showed that the glass transition temperature of the polyamide microfibre reduced following methyl methacrylate treatment. The ultimate consequence of all these functions was to facilitate diffusion of dye molecules into the microfibre, thereby increasing the colour strength. The wash fastness of the dyed samples was identical for the two different dyebaths, although there were slight differences in the staining grades. The rub fastness of the methyl methacrylate‐treated samples was improved by ca. half a grade. The methyl methacrylate had no effect on light fastness.     

Effects of pretreatment reagents on the hydrolysis and physical properties of PET fabrics

The effects of pretreatment reagents on the hydrolysis and physical properties of PET fabrics were investigated under various alkaline hydrolysis treatment and pretreatment conditions. Before alkaline hydrolysis, solvent treatment with pretreatment reagents, including benzyl alcohol (PET‐b) or 2‐phenyl ethanol (PET‐p), modified the structure of the PET fabric, thus affecting the hydrolysis and physical properties of the PET fabrics. Fabric weight loss increased with increasing hydrolysis time. The rate constant (k) increased markedly with increasing methyl groups in the pretreatment reagents. The activation energy (E_a) of untreated fabrics was higher than those of the treated fabrics. The crystallinity of the PET fabrics increased with increasing hydrolysis times (t) and methyl groups in the pretreatment reagents. The weight loss of PET‐b increased with increasing pretreatment temperature (T). However, the weight loss of PET‐p increased up to 100°C but decreased above 120°C. The shrinkage of all samples increased with increasing hydrolysis times (t). Shrinkage of PET‐b and PET‐p was greater than that of untreated fabrics. PET‐b displayed greater shrinkage than PET‐p because byproducts polluted the PET fibers. Both the initial and maximum water absorption of the fabrics increased with increasing hydrolysis times (t). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Diffusion and adsorption of dye by polyester microfibres

A comparatively greater quantity of dye is necessary to dye microfibre fabrics than conventional fabrics. This quantity depends on the fineness of the fibre and on the size of the dye molecule. A difference between the structure of the amorphous zones of polyester microfibres and conventional fibres can be invoked to explain this behaviour. This difference in structure also explains the poor mechanical behaviour of microfibre fabrics during the washing process, particularly polar fleece.     

Synthesis,characterization, and application of PVP/PAM copolymer

The aim of this study was to synthesize copolymers from N‐vinyl‐2‐pyrrolidinone (NVP) and acrylamide (AM) at different molar ratios and investigate the influence of the different ratios on copolymers' properties. How copolymers affect the washing and stain‐repelling effects of carbon black, PET, Nylon, or cotton fabrics was also evaluated. Results show that as the AM content increased, the copolymers decomposed more slowly by heat, indicating better heat stability. In addition, copolymers were characterized as lowering surface tension and having excellent dispersing ability, low foaming properties, and excellent acid and alkaline resistance. The addition of copolymer can produce stain‐repelling effects against carbon black, PET, or Nylon‐colored fabrics. It was also determined that fabrics' stain‐repelling effects have no significant relationship to the NVP/AM molar ratio in copolymer synthesis. However, carbon black has better stain repellence as the AM monomer content increased. Two types of stain repellence gave better results when a higher concentration of copolymer was added. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 2006     

Deep‐black‐coloring effect of fabrics made of noncircular cross‐section polyester filaments

The effects of noncircular cross‐section (NCCS) poly ethylene terephthalate (PET) filaments and its shape factor on deep‐black‐coloring of dyed fabrics were investigated by comparing to that of the circular cross‐section PET ones. Indexes such as K/S, L* and Integ values were used for characterizing the deep‐black‐coloring effect on fabrics. The results indicated that fabrics made with NCCS PET filaments exhibited good deep‐black‐coloring effects. The calculated shape factor of the NCCS PET fiber had a significant correlation with the degree of deep‐black‐coloring exhibited by the fabric made from the fibers. A qualitative optical analysis of the NCCS PET fibers was carried out to explain the causes of the deep‐coloring of the NCCS fibers. This analysis implies that the contours of the NCCS fiber composed of surfaces with varied curvature increase the scattering of light by lowering specular reflection and increasing interior reflected and refracted light. This, in turn, strengthens the deep‐coloring effect. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 511–518, 2014     

Use of regression methods for determining the relation between theoretical–linear and spectrophotometrical colour values of bicolour woven structures

In this paper, new approaches for evaluating the entire colour effect of optical mixing of bicolour woven structures are presented. Simple woven structures with constant colour in the warp direction and different colours in the weft direction were prepared and analysed. The constructional parameters of these woven fabrics were systematically changed, which resulted in the variations of the fractions of colour components and, consequently, also in the changes of colour properties (lightness, hue, chroma) of bicolour optical mixtures. The position of colours of the bicolour structures and the approximate direction (linear) of colour changes in CIELAB colour space were theoretically determined with a simple geometrical model and additive method. Furthermore, the bicolour optical effects were determined spectrophotometrically. The differences between the linear–theoretical and the spectrophotometrical colour values of bicolour woven fabrics were mathematically analysed with linear and non‐linear regression methods to determine the positions of colour coordinates L*, a* and b* of bicolour woven fabrics in the a*b* plane by increasing or reducing the cover factors of warp and weft threads (addition or reduction of colour components). The results present, on the one hand, the strong influence of original colours of warp and weft threads and, on the other hand, the minor influence of constructional parameters on the form of linear/non‐linear behaviour of colours of bicolour compositions. When the characteristics of a specific colour combination are taken into account, the spectrophotometrical colour values of bicolour woven fabrics can be also mathematically determined with additive–theoretical colour values and, to some extent, with predictable colour deviations.     

Preparation of hydrophilic woven fabrics: Surface modification of poly(ethylene terephthalate) by grafting of poly(vinyl alcohol) and poly(vinyl alcohol)-g-(N-vinyl-2-pyrrolidone)

One of the most industrially important synthetic textile materials, woven poly(ethylene terephthalate) (PET) fabrics, have limitations in the usage of casual apparel applications due to their unwanted hydrophobicity. For that reason, in this study, to impart permanent hydrophilicity to the PET fabrics, hydrophilic poly(vinyl alcohol) (PVA) and a PVA-based copolymer were introduced to the alkaline hydrolysis pretreated PET surface by graft copolymerization for the first time. The graft modification of PET fabric surface was performed with an industrial-adaptable approach. The synthesis of a novel PVA-g-(N-vinyl-2-pyrrolidone) copolymer was achieved by the introduction of glycidyl methacrylate monomer to the PVA backbone. The structure of the copolymer was evidenced by attenuated total reflection–Fourier transform infrared spectroscopy and ¹H-NMR techniques. The introduction of PVA and copolymer structures with desired functional groups to the PET fabric surface was confirmed with the X-ray photoelectron spectroscopy technique. It was obtained that the contact angle–wetting time of PET fabric (145° and 98 s) could be dropped to 37° and 0.1 s and 64° and 0.7 s after PVA and copolymer grafting, respectively. This suggests that the graft-modified PET fabrics may find the potential of use in the textile applications as the alternative hydrophilic materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48584.     

The surface polymerising of fluoromonomer and the shade-darkening effect on dyed polyester microfibre fabric

The surface polymerising of fluoromonomer on dyed polyester microfibre fabric is investigated. The shade-darkening effect of perfluoropolyester acrylate polymer is discussed by colour yield, reflectance spectrum and the colour differences. The surface polymerising of fluoromonomer on dyed polyester microfibre fabric had an excellent shade-darkening effect. After surface polymerising, the dyed fabrics had no significant effect on washing and wet rubbing fastness.     

Non-isothermal Crystallization Kinetics of Poly (Ethylene Terephthalate)/Grafted Carbon Black Composite

Summary The grafted carbon black (GCB) was prepared by in-situ grafting low molecular weight compound on the surface of carbon black (CB) using a new technique. Poly(ethylene terephthalate)/grafted carbon black (PET/GCB) and poly(ethylene terephthalate)/ carbon black (PET/CB) composites were prepared by melt blending. The non-isothermal crystallization process of virgin Poly(ethylene terephthalate)(PET), PET/CB, and PET/GCB composites were investigated by differential scanning calorimetry (DSC), and the non-isothermal crystallization kinetics was analyzed using different approaches, i.e. modified Avrami equation, Ozawa equation and the method developed by Liu. The effective energy barrier ΔE of virgin PET, PET/CB, and PET/GCB composites were calculated using the differential iso-conversional method. All of the results showed that GCB and CB acted as nucleating agents and increased the crystallization rate of PET. Compared with CB, GCB was a more effective nucleator for PET.     

Antimicrobial finishing of regular and modified polyethylene terephthalate fabrics

An effective two-stage method has been developed for imparting antimicrobial properties to regular polyethylene terephthalate (R-PET), polyethylene glycol modified polyethylene terephthalate (PEG-M-PET), R-PET/Cotton blend (R-PET/C) and PEG-M-PET/Cotton blend (PEG-M-PET/C) fabrics. The method consists of partial hydrolysis of the fabrics to create carboxylic groups in PET macromolecules followed by subsequent reaction with dimethylalkylbenzyl ammonium chloride (DMABAC) under alkaline conditions. The reaction conditions such as pH, reaction temperature and time, carboxylic content, and DMABAC concentration were studied. Characterization of the finished fabrics was carried out through scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR). All the modified PET fabrics showed excellent antibacterial activity towards Gram-positive (Bacillus mycoides), Gram-negative (Escherichia coli), and nonfilamentous fungus (Candida albicans). The achieved antimicrobial functions on the PET fabrics are durable in repeated laundering processes. Even after laundering 10 times the fabrics could still provide more than 85% of its antimicrobial activity against B. mycoides, E. coli, and C. albicans. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Alkaline dissolution monitoring of radial‐type polyester microfiber fabrics by a cationic dye‐staining method

The alkaline dissolution behavior of radial‐type polyester microfibers during high‐temperature alkali treatment and cold‐pad batch alkali treatment was successfully monitored using a cationic dye‐staining method. The weight reduction behavior of the alkali‐treated microfiber fabrics and their staining behavior with a cationic dye were compared. In addition, the termination of dissolution monitored by both methods was confirmed by scanning electron microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 279–285, 2006     

The microstructural and mechanical properties of geopolymer composites containing glass microfibres

This paper presents the effects of microfibre contents on mechanical properties of fly ash-based geopolymer matrices containing glass microfibres at 0, 1, 2 and 3 mass%. The influence of glass microfibres on the fracture toughness, compressive strength, Young's modulus and hardness of geopolymer composites are reported, as are the microstructural properties investigated using scanning electron microscopy. Results show that the addition of 2 mass% glass microfibres was optimal, exhibiting the highest levels of fracture toughness, compressive strength, Young's modulus and hardness. The results of the microstructural analysis indicate that the glass microfibres act as a filler for voids within the matrix, making a dense geopolymer and improving the microstructure of the binder. This leads to favourable adhesion of the composites, and produces a geopolymer composite with good mechanical properties, comparable to pure geopolymer. The failure mechanisms in glass microfibre-reinforced geopolymer composites are discussed in terms of microstructure.     

Alkali dissolution behaviour of sea–island‐type polyethylene terephthalate ultramicrofibre knitted fabrics

Sea–island‐type polyethylene terephthalate ultramicrofibre (0.007 denier per filament) with a single fibre diameter of ca. 800 nm has been produced over the last 4 years. Three kinds of sea–island‐type polyethylene terephthalate knitted fabric manufactured from this ultramicrofibre were alkali treated, and their dissolution behaviour was investigated. It was found that the dissolution ratio was dependent upon temperature and sodium hydroxide concentration in the alkali treatment. Practical dissolution ratios mostly reached the theoretical values after alkali treatment with 1.0% (w/w) sodium hydroxide solution at 95 °C for 40 min in all samples. Alkali dissolution of the sea component and revealing of the island component were confirmed by differential scanning calorimetry and scanning electron microscopy. Alkali dissolution behaviour could also be monitored indirectly by the cationic dye staining method. While all untreated samples exhibited high colour yield values after cationic dyeing, alkali‐treated samples showed reduced colour yield values with increasing alkali treatment time and a final levelling‐off point.     

Atmospheric pressure plasma‐induced decolorisation of cotton knitted fabric dyed with reactive dye

The aim of this study was to investigate the decolorisation effect of atmospheric pressure plasma treatment on knitted fabrics dyed with reactive dyes under different processing parameters, ie, air concentration, treatment duration and water content. The fabrics were dyed with reactive dye of a blue colour, and the colour depths were 0.5%, 1.5% and 3.0% on weight of fabric. The colour properties of untreated and plasma‐treated fabric samples were evaluated by means of reflectance, K/S and relative unlevelness index. The colour properties were evaluated instrumentally and quantitatively in order to study the decolorisation effect induced by atmospheric pressure plasma treatment. Experimental results revealed that the desired decolorisation effect was heavily influenced by the atmospheric pressure plasma treatment processing parameters. Although the desired decolorisation effect could be obtained by controlling the processing parameters of the atmospheric pressure plasma treatment, the treatment did not provide any significant reduction in the bursting strength of the fabric.     

Mathematical relationship between the colour shade depth and the fibre count for disperse dyeing of polyester fibres

The colour shade depth of dyed microfibres is lighter than that of dyed conventional fibres even if there is no difference between the absorbed dye quantities ( M _t) within the fibre. This difference is due to the different light reflectance on the fibre surface for microfibre and conventional fibre, which have a different specific surface area. In this study, the simple mathematical relationship between the colour shade depth, the fibre counts (0.22, 0.56 and 1.46 dtex) and the adsorbed dye quantity is developed for disperse dyeing. The experimental dyeing results and the obtained dyeing results from the simple mathematical relationship were compared for different fibre counts.     

The colour and fastness of natural saffron

Cotton and wool fabrics have been dyed with the aqueous extract of saffron containing α-crocin as the main colorant species. The dyeings were carried out with and without metal salts as mordants. The wash and light fastness of the dyed fabrics was studied. The colour of the fabrics was investigated in terms of CIE L* C* H* values.     

Lipases improve the grafting of poly(ethylene terephthalate) fabrics with acrylic acid

In this study, poly(ethylene terephthalate) (PET) fabrics were modified with two types of commercial lipases, namely, Lipex and Lipolase, and grafted with acrylic acid (AA) to improve their absorption properties. The effects of the enzyme concentration, reaction temperature, time, and pH on the grafting of AA onto PET were investigated. The pretreatment of PET with lipases increased the amount of AA that was introduced to the PET fibers, whereas AA grafting onto the untreated PET fabrics led to lower graft yields. Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the AA‐grafted pretreated polyester fabrics. A new band appearing at 1546 cm^?1 in the Fourier transform infrared spectrum implied that AA was introduced onto the PET fabrics. The surfaces of the fabric fibers presented in scanning electron microscopy micrographs clearly indicated the formation of a layer of grafted poly (acrylic acid). The results show that the density of surface grafting was improved by the lipase pretreatment. The increase in grafting was higher for Lipex than for Lipolase. The highest graft yield was obtained with 1% Lipex and Lipolase for 30 min at pH values of 7 and 5, respectively. There were no significant changes in the tenacity or weight reduction of the fabrics. The moisture content of the samples increased linearly with increasing graft yield. This was higher for the pretreated fabrics grafted with Lipex. A higher color strength was obtained for grafted PET samples that were pretreated with Lipex when they were dyed in alkaline aqueous solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse dyes

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse red dye was studied in the temperature range 283–363 K. 1‐vinyl 2‐pyrrolidone (NVP), acrylic acid (AA) or their mixture was used to graft poly(ethylene terephthalate) (PET) fabric. The effects of pH of the dye solution, graft yield (GY), dyeing time (t), dye concentration (C), and dyeing temperature (T) on the colour difference (CD) of PET fabric were studied. The best dyeing condition was achieved at pH 5.5. CD increases linearly with the increase in GY, with slopes depending on the type of grafted copolymer. CD increased rapidly as the dyeing time increased; this was followed by a relatively slow dyeing rate within a few minutes. The initial dyeing rate (R) was found to increase with an increase in C and T. The dyeing rates for all grafted samples followed 0.35‐order kinetics and are temperature‐independent. Average activation energy 9.26 kJ mol^?1 is calculated for the dyeing process and is independent of the fabric treatment. Pre‐exponential rate constants 1976, 1839, and 1579 (CD/GY) s^?1 were calculated for dyeing PET samples grafted with AA/NVP mixture, NVP and AA, respectively, while 1074 CD s^?1 was evaluated for carrier dyeing of ungrafted fabric. Analysis of the kinetic parameters and the dyeing mechanism revealed that dyeing PET fabric was diffusion‐controlled. Grafting PET fabric improved significantly the dyeing affinity of the DR dye over ungrafted samples dyed in solutions containing a carrier. Copyright © 2005 Society of Chemical Industry     

CO2 laser irradiation of raw and bleached cotton fabrics,with focus on water and dye absorbency

In this research, the effect of carbon dioxide laser irradiation on various properties of raw and bleached cotton fabrics, including fabric weight, bending rigidity, wetting, and air permeability, as well as dyeing, was examined and compared. The experiments were carried out at three different laser powers ranging from 4.5 to 6 W to determine the effect of laser treatment on fabric properties. In particular, the influence of laser irradiation on the dyeing properties of treated fabrics with CI Reactive Blue 198 was studied. The colour change of laser‐treated fabrics was determined by calculation of the K/S values as a function of fabric reflectance. The morphological changes in laser‐treated fabrics were observed by scanning electron microscopy. The effects of laser treatment on the properties of raw and bleached cotton fabrics were varied. For instance, the wettability of raw cotton samples was reduced after laser irradiation, whereas the wettability of bleached cotton fabrics was greater. Possible reasons for the various dyeing behaviours observed with irradiation at different laser powers are discussed.