A novel strategy to improve the dyeing properties in laccase-mediated coloration of wool fabric

Enzymatic coloration of fabrics has received worldwide attention in recent years. In order to improve the dyeing properties of enzymatically coloured fabrics, a novel strategy using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), a biological coupling agent, to pretreat wool fabric was employed in this paper. Enzymatic coloration of wool fabrics with syringic acid was carried out in the presence of laccase from Trametes versicolor. The effect of different periods on laccase-catalysed polymerisation of syringic acid was examined by UV-vis spectroscopy. Enzymatic coloration results of dyed wool fabrics were evaluated by means of K/S value and colour difference (∆E*). Process parameters, including the dosages of syringic acid and incubation time, that influenced the colour depth were studied. Meanwhile, the colour fastness and levelness of dyed wool fabrics were tested. The results showed that the UV-vis absorbance of reaction solution increased as oxidation time elapsed, and a new peak appeared at 360 nm. After pretreatment, the K/S values and colour difference values of wool fabrics dyed with poly(syringic acid) improved appreciably compared with the control samples without any pretreatment. Moreover, pretreated wool fabrics showed better dyeing fastness and levelness than control samples.     

Surfactant properties of purified polyglycerol monolaurates

A series of purified polyglycerol monolaurates (PGML), such as di-, tri-, tetra-, and pentaglycerol monolaurates, were synthesized, and their surfactant properties in aqueous solutions were examined. The surfactant properties of PGML were compared with those of n-dodecyl polyoxyethylene monoethers (C₁₂EO_n) to examine the function of the hydrophilic part of these compounds. The critical micelle concentration (CMC) values and the surface tension at CMC of PGML and C₁₂EO_n increased linearly with an increase in the number of glycerol and oxyethylene units, respectively; the slope of the increase was greater for PGML than C₁₂EO_n. The minimum surface area per molecule of PGML was smaller than that of C₁₂EO_n at the air/aqueous solution interface. The initial foam heights of the surfactants at the CMC increased with an increase in the number of glycerol or oxyethylene units, and the foam heights of PGML were consistently higher and more stable than those of C₁₂EO_n. Detergency depended on a reduction in interfacial tension. Triglycerol monolaurate showed the lowest interfacial tension and the highest detergency among all the surfactants tested. Overall, the PGML showed better performance in all the surfactant properties tested than C₁₂EO_n. It is noteworthy that the surfactant properties of PGML having few glycerol units (di- to tetraglycerol monolaurates) are on par with those of C₁₂EO_n having many oxyethylene units (hexa- and octaoxyethylene). These results suggest that PGML having a secondary hydroxyl group on every glycerol unit of the hydrophilic part could be more hydrophilic than C₁₂EO_n; this characteristic feature guaranteed the superior surfactant properties of PGML.     

Lauryl alcohol and amine oxide as foam stabilizers in the presence of hardness and oily soil

The effects of two potential foam boosters, n-dodecanol (or lauryl alcohol: LA) and tetradecyldimethylamine oxide (C₁₄DMAO), were investigated for two situations in which foam made from a 0.01 wt% solution of a common alkylethoxy sulfate surfactant was highly unstable in the presence of oil drops consisting of an n-hexadecane/oleic acid mixture. In one case in which dissolved CaCl₂ was present at alkaline pH, insoluble calcium oleate particles formed in situ and facilitated foam breakage. In the other, a much higher concentration of calcium was present at neutral pH, and drops of a microemulsion phase formed but no calcium oleate. In both cases, 0.005 wt% LA reduced the entry coefficient, E, of the oil to the air-water surface sufficiently to prevent drop entry and stabilized the foam. In contrast, 0.005 wt% C₁₄DMAO caused smaller reductions in E and was ineffective as a foam booster. LA was more effective because it was able to form a more compact monolayer with the surfactant than C₁₄DMAO at the air-water surface, which led to lower surface tensions and hence lower values of E.     

Textile applications of photochromic dyes. Part 4: application of commercial photochromic dyes as disperse dyes to polyester by exhaust dyeing

A series of commercial photochromic dyes was applied to polyester fabric as disperse dyes. The photocoloration properties of the dyed fabrics were investigated by applying techniques previously established in our laboratories using an independent source of ultraviolet irradiation and traditional colour measurement instrumentation. The dyed fabrics showed reversible photochromism, developing pronounced colours from weak background colours on irradiation with ultraviolet light and returning to their original state when the ultraviolet light source was removed. However, the extent of photocoloration and the depth of background colour varied significantly with the particular dye used. The dyeing procedure was optimised by maximising the degree of photocoloration, expressed as the colour difference (ΔE₁) between the colour developed after ultraviolet exposure and background colour, while minimising the background colour, expressed as the colour difference (ΔE₂) between unexposed dyed and undyed fabrics. Optimum dyeing concentrations were determined. The colour development and fading properties, fatigue resistance and storage stability of the dyed fabrics were investigated.     

Cetylpyridinium chloride cationic finishing improves the dyeing and antibacterial properties of madder dyed cotton

In this work, after cationic pretreatment of cotton fabric with cetylpyridinium chloride (CPC), the compound of citric acid (CA) and succinic acid (SUA) were used as crosslinking agents to dye cotton fabrics with natural madder dye to improve the dyeing and antibacterial properties and realise the multifunctional finishing of cotton fabric. The effects of mordant dyeing, CA + SUA crosslinked dyeing, and CPC/CA + SUA crosslinked dyeing on the microstructure and properties of cotton fabrics were compared. The dyeing by the three processes occurred primarily in the amorphous zone of the fibres, and all kept the original crystalline form of the cotton. CA + SUA crosslinked dyeing and CPC/CA + SUA crosslinked dyeing increased the thermal stability of the cotton fabric. CPC/CA + SUA crosslinked dyed cotton obtained excellent dyeing results with the colour depth value (K/S) of 12.3 and rubbing fastness and washing fastness of levels 4–5, and the levelness and dye permeability were acceptable. Furthermore, the antibacterial rate against Escherichia coli and Staphylococcus aureus reached 99.99%, and the ultraviolet protection factor (UPF) reached 50+. Moreover, the wrinkle recovery angle (WRA) increased by 55% compared with raw cotton. This showed that CPC/CA + SUA crosslinked dyed cotton had excellent antibacterial, anti-ultraviolet, and anti-wrinkle performances.     

Synthesis of an Alkyl Polyoxyethylene Ether Sulfonate Surfactant and Its Application in Surfactant Flooding

Surfactant flooding as a potential enhanced oil‐recovery technology in a high‐temperature and high‐salinity oil reservoir after water flooding has attracted extensive attention. In this study, the synthesis of an alkyl alcohol polyoxyethylene ether sulfonate surfactant (C₁₂EO₇S) with dodecyl alcohol polyoxyethylene ether and sodium 2‐chloroethanesulfonate monohydrate, and its adaptability in surfactant flooding were investigated. The fundamental parameters of C₁₂EO₇S were obtained via surface tension measurement. And the ability to reduce oil–water interfacial tension (IFT), wettability alteration, emulsification, and adsorption was determined. The results illustrated that IFT could be reduced to 10^?3 mN m^?1 at high temperature and high salinity without additional additives, and C₁₂EO₇S exhibited benign wettability alternate ability, and emulsifying ability. Furthermore, the oil‐displacement experiments showed that C₁₂EO₇S solution could remarkably enhance oil recovery by 16.19% without adding any additives.     

Foam properties and application in dyeing cotton fabrics with reactive dyes

The foam dyeing of cotton fabric with CI Reactive Red 120 has been studied as a low‐add‐on technology. The foamability of different types of foaming agent and the stability of foam stabilisers were compared. Factors influencing foam dyeing, including wet pick‐up, fixation agent, foam stabiliser, and blow ratio, were evaluated by colour strength and dye fixation rate. Wet pick‐up, fixation agent, and foam stabiliser were found to be the main factors in the foam dyeing process. The comparative build‐up properties, dyeing properties, and total consumption between foam dyeing and conventional dyeing were assessed. The results indicate that, in foam dyeing, the dyestuff has a better build‐up property, the dyed fabric has excellent wash and rub fastness, and large amounts of water and energy are saved. Moreover, foam dyeing requires smaller dosages of chemical agents and reduces the difficulty of effluent treatment.     

Effects of clay dispersion on the foam morphology of LDPE/clay nanocomposites

Intercalated and exfoliated low‐density polyethylene (LDPE)/clay nanocomposites were prepared by melt blending with and without a maleated polyethylene (PE‐g‐MAn) as the coupling agent. Their morphology was examined and confirmed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of clay content and dispersion on the cell morphology of nanocomposite foams during extrusion foaming process were also thoroughly investigated, especially with a small amount of clay of 0.05–1.0 wt%. This research shows the optimum clay content for achieving microcellular PE/clay nanocomposite foams blown with supercritical CO₂. It is found that < 0.1 wt% of clay addition can produce the microcellular foam structure with a cell density of > 10⁹ cells/cm³ and a cell size of ～ 5 μm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2129–2134, 2007     

Effect of oil viscosity on recovery processes in relation to foam flooding

Laboratory experiments were conducted to determine the effect of oil viscosity on the oil-recovery efficiency in porous media. The pure surfactants (i.e., sodium dodecyl sulfate and various alkyl alcohols) were selected to correlate the molecular and surface properties of foaming solutions with viscosity, and the recovery of oil. Oil-displacement efficiency was measured by water, surfactant-solution and foam-flooding processes, which included 2 types of foams (i.e., air foam and steam foam). A significant increase in heavy-oil recovery was observed by steam foam flooding compared with that by air foam flooding, whereas for light oils, the steam foam and air foam produced about the same oil recovery. An attempt was made to correlate the chain-length compatibility with the surface properties of the foaming agents and oil-recovery efficiency in porous media. For mixed foaming systems (C₁₂ SO₄ Na + C_n H_2n+1 OH), a minimum in surface tension, a maximum in surface viscosity, a minimum in bubble size and a maximum in oil recovery were observed when both components of the foaming system had the same chain length. These results were explained on the basis of thermal motions (i.e., vibrational, rotational and oscillational) and the molecular packing of surfactants at the gas-liquid interface. The effects of chain-length compatibility and the surface properties of mixed surfactants are relevant to the design of surfactant formulations for oil recovery under given reservoir conditions.     

Effects of Inorganic Salts and Polymers on the Foam Performance of 1-Tetradecyl-3-methylimidazolium Bromide Aqueous Solution

The foaming performance of 1-tetradecyl-3-methylimidazolium bromide (C₁₄mimBr) aqueous solution, in the presence of polymers (PEG or PVA) or inorganic salts (NaBr, MgCl₂, NaNO₃, Na₂SO₄ or Na₃PO₄), was investigated at 25.0?°C by using the self-made apparatus and the conductivity method. The experimental results show that the foaming ability and foam stability of the ternary aqueous systems of C₁₄mimBr coexisting with PEG or PVA are stronger than those of the C₁₄mimBr solutions in the absence of a polymer, and both the efficiency of foaming ability and foam stability of the surfactant solutions are evidently enhanced with an increase in polymer concentration. However, the addition of inorganic salts can decrease the foaming ability and foam stability of C₁₄mimBr solution. Especially, the inorganic salts, with high valence state of the anion (SO₄ ^2? and PO₄ ^3?), are good antifoam agents which can remove and inhibit foam quickly. For the aqueous solution of the surfactant, the effect of temperature on foaming properties was also examined. The results show that both the foaming ability and stability of the foams of the surfactant solutions decrease with an increase in the temperature within the range from 25.0 to 45.0?°C.     

Vinyl-functionalized polyborosiloxane for improving mechanical and flame-retardancy performances of silicone rubber foam composites

In this work, we first synthesized vinyl-terminated polyborosiloxane (pBS) filler, and then incorporated it into silicone rubber foam (SRF) matrix to prepare composite materials through a simple chemical dehydrogenative foaming method under ambient conditions. The pBS filler with reactive groups could form physical and chemical crosslinking networks in SRF, leading to an excellent dispersion level of pBS in the SRF matrix. Moreover, the inserted pBS could remarkably improve the mechanical and flame-retardancy properties of SRF-pBS composites. Intriguingly, the SRF-pBS6 foam containing 6 wt% of pBS possessed a uniform porous structure and balanced mechanical properties (σ_b = 65.4 kPa, ε_b = 56.7%, compression stress 97.1 kPa), thermal conductivity (0.102 W (m K)^?1), limiting oxygen index (29.8%) and UL-94 rating (V-0) among the prepared foams. In addition, the incorporated pBS (6 wt%) could synergistically catalyze the formation of a silicon–boron strengthened ceramic-like protective layer under fire and was capable of suppressing heat and smoke production in the SRF-pBS6 foam. The present work provides a promising way for developing high mechanical and flame-retardant polymeric foam materials with good thermal insulation. © 2021 Society of Industrial Chemistry.     

Adsorption behaviour of carbon black/latex by cationised cotton fabrics

A carbon black/latex dispersion was prepared by mini‐emulsion polymerisation, and its absorption behaviour towards cationised cotton fabric was investigated. The results indicated that the prepared carbon black/latex dispersion had excellent freeze–thaw stability. Cotton fabric that was cationised with 3 g/l of 3‐chloro‐2‐hydroxypropyltrimethyl ammonium chloride at a liquor ratio of 30:1 can be optimally dyed with 4% owf carbon black/latex under the conditions of pH 7.2, 60 °C, and 1 h. The adsorption behaviour of the carbon black/latex towards cationised cotton fabric followed the Langmuir adsorption isotherm, with a lower dyeing rate and a better colour levelness than the ordinary carbon black dispersion with binder.     

直链型偶氮苯聚氧乙烯醚稳泡剂的制备及表面活性

以4-羟基偶氮苯、1,2-二溴乙烷、PEG-600为原料,合成直链型偶氮苯聚氧乙烯醚非离子表面活性剂(PEP-600)。通过红外光谱和核磁共振氢谱表征了其结构,并测试了其表面活性。结果表明,PEP-600临界胶束浓度(CMC)为4.99×10~(–3) mol/L,在CMC处表面张力为48.09 mN/m,饱和吸附量为2.48×10~(–3) mmol/m~2,亲水亲油平衡值(HLB)为14.20。将PEP-600与0.1 g/L的十二烷基硫酸钠复配最大发泡比为12,泡沫半衰期为220s左右,直链型分子结构的PEP-600在泡沫液膜表面排列紧密,具有优异的起泡性能,可用作泡沫染整稳泡剂。     

Effect of ionic strength on the foam fractionation of BSA with existence of antifoaming agent

Foam fractionation is an economical and effective technology for protein concentration and separation. However, the presence of antifoaming agent in the fermentation broth restricts the application of this technology. In this paper surfactant-assisted foam process was conducted with a mimic system using bovine serum albumin (BSA) as target protein, polyoxypropylene polyoxyethylene glylerin ether (PGE) as antifoaming agent and cetyltrimethyl ammonium bromide (CTAB) as surfactant, putting emphasis on study of the effect of ionic strength on the separation process. The experimental results showed that with ionic strength increasing, the mixed-system foaming ability gradually increased. Under the conditions of C_BSA 100 mg/L, C_CTAB 20 mg/L, C_PGE 8 mg/L and pH 7.4, feed liquid 250 mL, air flow rate 100 mL/min at 25 °C, the maximum enrichment ratio of BSA reached 27 when the ionic strength was 0.0500 mol/kg and the maximum recovery of BSA reached 80.5% when the ionic strength was 0.1696 mol/kg. Furthermore, K⁺ had better separate efficiency than Na⁺ under the same ionic strength.     

Reuse of ash-tree (Fraxinus excelsior L.) bark as natural dyes for textile dyeing: process conditions and process stability

The aqueous extract of ash-tree bark ( Fraxinus excelsior L.) was chosen as a model to study the shade reproducibility of dyeing on wool. A meta-mordanting process using FeSO₄·7H₂O mordant was chosen as a system with particular potential for industrial application. The exhaust dyeing process with immediate use of the extracts as a dyebath and direct addition of FeSO₄·7H₂O stock solution as a meta-mordant process showed good shade reproducibility and satisfying levelness of the dyed material. An increase of Fe( ii )-mordant above a dyebath concentration of 2–3 g l⁻¹ did not result in further colour depth. Extraction of 1–2 g of bark was found sufficient to dye 1 g wool yarn to the darkest colour possible; use of higher amounts of bark did not yield substantially higher colour depth. The quality of bark and the extraction step were found to be of significant importance for the colour depth; thus, in an optimised process, conditions of extract formation have to be well controlled.     

泡沫复合驱配方ZS-23的研究

泡沫驱作为一项重要的三次采油技术,在降低气油比、增加原油产量、提高波及效率等诸多方面具有很大的发展潜力。对ZS系列泡沫复合驱配方进行了探索性研究,使用Waring Blender法对泡沫复合驱配方的发泡能力和稳定性进行了检测,通过实验筛选出发泡性能好、稳定性强的泡沫复合驱配方。在矿化度NaCl>5 000 mg/L、CaCl2>3 000 mg/L条件下,表现最为优异的配方为ZS-23,在常温(20℃)时,发泡体积达到880 mL,析液半衰期5.3 h以上,加盐后发泡体积达到820 mL,析液半衰期3.5 h以上,均远远好于一般常见的发泡剂。     

新型ZS-5复合驱泡沫配方的研制

使用Waring Blender法对7种常见起泡剂的发泡能力和稳定性进行了检测。通过复配增效和抗盐检测,发现常温下(20℃)AOS、AES、AOS+AES的最大泡沫体积都在1 080 mL以上,在含盐条件下稳定性也较好。然后将三者与常见的稳定剂进行复配,发现XC、十二醇能够在前述条件下明显提高起泡剂的稳定性,两者复配加入时效果更佳。在此基础上合成了ZS系列复合驱配方。在矿化度含量NaCl>5 000 mg/L、CaCl2>3 000 mg/L条件下,将该系列配方与两种常见的配方进行了比较,其中ZS-5在常温下(20℃)泡沫体积达到990 mL,析液半衰期3.5 h以上,加盐后泡沫体积仍达到860 mL,析液半衰期2.5 h以上,均远远好于一般常见的发泡剂。     

Synergistic Effects between Anionic and Sulfobetaine Surfactants for Stabilization of Foams Tolerant to Crude Oil in Foam Flooding

In foam flooding, foams stabilized by conventional surfactants are usually unstable in contacting with crude oil, which behaves as a strong defoaming agent. In this article, synergistic effects between different surfactants were utilized to improve foam stability against crude oil. Targeted to reservoir conditions of Daqing crude oil field, China (45 °C, salinity of 6778 mg L⁻¹, pH = 8–9), foams stabilized by typical anionic surfactants fatty alcohol polyoxyethylene ether sulfate (AES) and sodium dodecyl sulfate (SDS) show low composite foam index (200–500 L s) and low oil tolerance index (0.1–0.2). However, the foam stability can be significantly improved by mixing the anionic surfactant with a sulfobetaine surfactant, which behaves as a foam stabilizer increasing the half-life of foams, and those with longer alkyl chain behave better. As an example, by mixing AES and SDS with hexadecyl dimethyl hydroxypropyl sulfobetaine (C₁₆HSB) at a molar fraction of 0.2 (referring to total surfactant, not including water), the maximum composite foaming index and oil tolerance index can be increased to 3000/5000 L s and 1.0/4.0, respectively, at a total concentration between 3 and 5 mM. The attractive interaction between the different surfactants in a mixed monolayer as reflected by the negative β^s parameter is responsible for the enhancement of the foam stabilization, which resulted in lower interfacial tensions and therefore negative enter (E), spreading (S), and bridging (B) coefficients of the oil. The oil is then emulsified as tiny droplets dispersed in lamellae, giving very stable pseudoemulsion films inhibiting rupture of the bubble films. This made it possible to utilize typical conventional anionic surfactants as foaming agents in foam flooding.     

Polyhedral alumina foam

The presented paper reports on the results of preparation of alumina foam with ideal polyhedral shapes of bubbles-pores. The foam was prepared by direct foaming method using partially hydrophobized Al₂O₃ particles, where dodecylbenzenesulfonic acid was used as a hydrophobization agent. A polyhedral shape of the bubbles was achieved by “water procedure”, in which the alumina foam prepared by the direct foaming method was poured into twice its volume of water and mixed. After the mixing was stopped, the particles with an inadequate contact angle were washed out from the system of the alumina foam by draining. The foam was formed only from particles which were physically bound in the lamellas and the bubbles were arranged in ideal polyhedral shapes. The water procedure increases the foam stability, allowing for preparation of alumina foams with porosity of 99 %.     

Prediction of recipes for cotton cationisation and reactive dyeing to shade match conventionally dyed cotton

Cationisation allows cotton to be dyed with anionic dyestuffs (including anionic pigment dispersions) without the need for salt, and with decreased usage of dye, water, and energy. Appropriate cationisation levels play a part in dyeing properties such as fabric levelness, in fastness properties such as lightfastness, and in the overall cost of the cationisation treatment. The objective of this work is to assess whether it is possible simultaneously to predict a dye recipe and cationisation treatment level for cotton to yield a colourless or nearly colourless dyebath at the completion of the dyeing to match the shade of conventional fibre reactive dyeing of cotton. It has been shown that it is possible to model a cold pad batch cationisation process, relate the colour yield data and cationisation level for individual dyes, and finally predict a dyeing recipe and the required corresponding cationisation treatment to match the shade of conventional fibre reactive dyeing of cotton. The predicted dye recipe and cationisation amount yield colourless or nearly colourless dyebaths at the conclusion of the dyeing process.