Photochromism of 6-nitrospiropyran in oriented polyethylene

Summary UV-VIS and IR dichroism spectra of 1,3,3-trimethyl-6-nitrospiro(2H-1-benzopyran-2,2-indoline) (6-NSP) dispersed in stretched low density poly(ethylene) (PE) films are reported. Also the kinetics of the thermally induced decay of merocyanine (Mc) form of 6-NSP was investigated in both nonoriented and oriented samples using polarized light. The analysis of experimental data reveals that decoloration processes is faster in the stretched than in the nonstretched matrix. This is opposite to the photochromic phenomena occurring in stretched rubbers when the chromophores are bound chemically to the polymer.     

Photochromic polymers

Summary Two soluble photochromic polymers containing 1-(ß-hydroxyethyl)-3,3-dimethyl-6-nitrospiro[2H-1-benzopyran-2,2-indoline] bound on a variously long side chain were prepared. It was found that the discolouration process depends on the length of the side chain to which the photochromic centre is bound.     

Fragrant finishing of cotton with microcapsules: comparison between printing and impregnation

Microencapsulated fragrance was used to produce a fragrant textile product. Melamine–formaldehyde polymer wall microcapsules with a lavender, rosemary and sage essential oil core were applied to a cotton fabric in two ways, i.e. byscreen printing and impregnation. The samples were dried and cured, and then the differences between them were analysed. The condition and distribution of applied microcapsules were observed by scanning electron microscopy, fragrance evaluation was performed on printed and impregnated samples after they had been washed several times, and their handle properties were investigated. Moreover, the influence of artificial light on the wall of microcapsules was examined, and possible antibacterial activity against Staphylococcus aureus and Escherichia coli was evaluated. The change in colour of all samples as a consequence of the addition of microcapsules to the paste or bath was checked. The results show that both application techniques are appropriate for the effective fragrant but on the other hand ineffective antibacterial finishing of cotton fabrics. Artificial light did not affect the microcapsules. There is an impact on colour only when the capsules are printed to fabric. Both of the techniques used, printing and impregnation, have advantages as well as drawbacks.     

Direct coloration of textiles with photochromic dyes. Part 1: Application of spiroindolinonaphthoxazines as disperse dyes to polyester,nylon and acrylic fabrics†

1,3,3‐Trimethylspiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine ( 1a ) and 6′‐piperidino‐1,3,3‐trimethylspiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine ( 1b ) were applied as disperse dyes to polyester, nylon and acrylic fabrics. Under optimised dyeing conditions, photochromic fabrics were produced which, on irradiation with ultraviolet or exposure to sunlight, turned blue ( 1a) or blueish‐purple ( 1b ). Dye 1a showed enhanced photochromic colour change performance compared with dye 1b . The photochromic colour build was highest on nylon and lowest on acrylic fabric. The colour change properties and the technical performance (wash fastness and photostability) of the photochromic fabrics were evaluated using specifically adapted colour measurement methods. The data were analysed in terms of variation of lightness, a*, b*, chroma, hue angle and ΔE, colour difference before and after exposure, and K/S curves as a function of irradiation time. The fabrics generally showed good wash fastness. Although the colour build‐up decreased with exposure to the Xenotest fadeometer, some residual photochromism remained after prolonged exposure.     

An investigation of an instrument‐based method for assessing colour fastness to light of photochromic textiles

A new method for evaluating the light fastness of photochromic fabrics was established, aimed at replacing the conventional method with an instrumental method. This method was based on comparing the colour difference of photochromic fabrics after light exposure with measured values of the colour differences of the blue wool references after fixed periods of light exposure. This method benefits from replacing the traditional visual evaluation of colour difference between exposed and unexposed areas of textile samples with a more accurate, instrument‐based measurement of the colour difference. The light fastness is then evaluated by comparing the colour difference with tabulated values of colour differences brought about by light exposure, for increased periods of time, of standard blue wool references. This method could be used for measuring light fastness of both traditional and photochromic fabrics. However, blue wool references and tested samples should be exposed to light under similar conditions when using this method to measure colour fastness to light of fabrics.     

Photochromic properties of color‐matching,double‐shelled microcapsules covalently bonded onto cotton fabric and applications to outdoor clothing

In this research, we aimed to apply color‐matching, double‐shelled microcapsules to deal with outdoor‐clothing sunscreen‐indicator identifications on cotton fabrics with a covalent‐bonding coating method; this method allows one to display both the UV intensity and a warning. The color‐property characteristics of color‐matching‐double‐shelled‐photochromic‐microcapsule–treated patterns on cotton fabrics under various sunshine irradiation intensities are very close to those of inkjet‐printing color‐gradation patterns, which indicate sunshine irradiation intensities. Color‐matching, double‐shelled microcapsules were obtained by the addition of red double‐shelled microcapsules into yellow double‐shelled microcapsules. We increased the weight ratio of the red microcapsules and added blue double‐shelled microcapsules into the red double‐shelled microcapsules when the weight ratio of blue microcapsules was increased. Color‐matching, double‐shelled photochromic microcapsules, whose yellow/red/blue weight ratios were 5.6/0/0, 4.8/0.8/0, 2.4/3.2/0, and 0.8/4.8/0–0/0/5.6, presented distinct color‐property characteristic changes under various irradiation intensities and presented a good color identification; a rather dark, bright color; and good laundering durability of covalent bonding on cotton fabrics. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44698.     

Textiles screen‐printed with photochromic ethyl cellulose–spirooxazine composite nanoparticles

Photochromic compounds change colour on exposure to light, while the reversion may be attributable either to radiation or may be thermal. The use of photochromism on fabrics can provide new opportunities to develop smart textiles; for example, sensors and active protective clothes. Ethyl cellulose‐1,3‐dihydro‐1,3,3,4,5 (and 1,3,3,5,6) ‐pentamethyl‐spiro‐[2H‐indole‐2,3′‐(3H)naphtha(2,1‐b)(1,4)oxazine] composites were prepared by an oil‐in‐water emulsion, solvent evaporation method in order to form easily suspendable and fatigue‐resistant photochromic nanoparticles in screen‐printing paste. Their size was well below 1 μm and did not change substantially over a wide range of dye concentrations. After screen‐printing, a homogenous photochromic layer was built on a cotton substrate surface, which represented substantial blue colour development in CIELab colour space measurements because of ultraviolet light, even at a dye concentration of 0.045% w/w. The addition of a photodegradation inhibitor, Tinuvin 144, further increased the coloration of the printed fabric.     

Ink‐jet printing of cotton with natural dyes

Four natural dyes, annatto, cutch, pomegranate fruit rind, and golden dock, were used as colorants for the preparation of water‐based ink‐jet inks for digital textile printing. The physical and rheological properties (pH, conductivity, surface tension, and viscosity) of the inks were measured over a period of 90 days for the evaluation of ink stability and suitability for ink‐jet printing. The inks were found to be suitable and were used for the digital printing of cotton fabrics. The prints were subjected to wash, light, and rub fastness tests and colour measurements. Colour consistency and fastness results, especially after fixation, are comparable with those of synthetic dyes, which paves the way for the production of environmentally friendly ink‐jet inks using natural dyes for the digital printing of cotton through the formulation of suitable printing techniques.     

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.     

Development of thermoregulating textile materials with microencapsulated phase change materials (PCM). II. Preparation and application of PCM microcapsules

Melamine–formaldehyde microcapsules containing eicosane were prepared by in situ polymerization. The characterization of the microcapsules, including the particle size and size distribution, morphology, thermal properties, and stability, was carried out. The prepared microcapsules were added to polyester knit fabrics by a conventional pad–dry–cure process to develop thermoregulating textile materials. The morphology, thermal properties, and laundering properties of the treated fabrics were also investigated. The microcapsules were spherical and had melamine–formaldehyde shells containing eicosane. The microcapsules were strong enough to secure capsule stability under stirring in hot water and alkaline solutions. The heat storage capacity increased as the concentration of the microcapsules increased. The thermoregulating fabrics had heat storage capacities of 0.91–4.44 J/g, which depended on the concentration of the microcapsules. The treated fabrics retained 40% of their heat storage capacity after five launderings. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2005–2010, 2005     

Pretreatment effects on pigment‐based textile inkjet printing – colour gamut and crockfastness properties

The application of two commercial pretreatment agents, formulated to improve the performance of a six‐colour nano‐scale pigment ink set during the textile inkjet printing of cotton and polyester (PET) fabrics, was examined. An industrial scale printer, operating at 55 linear m/h and equipped with Kyocera printheads, was used to print on commercial fabrics (180 cm wide) prepared for digital printing. The work employed an industrial scale rather than a benchtop printer to enhance the utility of the results for a commercial environment. The colorimetric attributes of printed fabrics were recorded for the individual inks as well as for spot colour combinations generated using Dr. Wirth RIPMaster v11 software. Colour table profiles were also generated and the colorimetric values of inks were compared. Colour gamuts of inks on cotton and PET, including three‐dimensional volumes in the CIELab space, were examined to assess the role of pretreatment on the colorimetric properties of the printed substrates. It was found that the pretreatments enhanced the ink receptiveness, colour intensity and colour gamut of fabrics. Pretreatment of cotton resulted in a larger gamut and more vivid colours than on PET. However, wet and dry crockfastness results were found to be low. In this regard, Time‐of‐Flight Secondary Ion Mass Spectrometry analysis of fabrics printed in the presence and absence of pretreatment indicated that the low crockfastness arises from higher pigment levels on the surface of the pretreated fabric.     

The study of colour fastness of commercial microencapsulated photoresponsive dye applied on cotton,cotton/polyester and polyester fabric using a pad‐dry‐cure process

Commercial microencapsulated photoresponsive dye was applied on cotton, polyester/cotton and polyester fabric using a pad‐dry‐cure process. Colour fastness of the photoresponsive fabrics to washing, wet cleaning, dry cleaning, rubbing and light was investigated. The CIELAB colour values of the fabrics before and after testing were measured using a reflectance spectrophotometer, and the colour differences were calculated to evaluate the fastness properties. The fabrics had better colour fastness to wet cleaning and washing than to dry cleaning. The fabrics showed higher colour fastness to wet than to dry rubbing. The photoresponsiveness of the fabrics decreased with prolonged exposure time to artificial light due to low photostability of the microcapsules.     

Silylation-Mediated Oxidation of 2,2′-Anhydro-5,6-dihydro-5-azacytidine

Reaction of 5,6-dihydro-5-azacytidine hydrochloride 1 with 2-acetoxy-isobutyryl chloride produced 5′-O-(2,5,5-trimethyl-1,3-dioxolan-4-on-2-yl)-3′-O-acetyl-5,6-dihydro-2,2′-anhydro-1-β-D-arabinofuranosyl-5-azacytosine hydrochloride 2 , which upon partial hydrolysis with EtOH/HCl at 4°C gave 3′-O-acetyl-5,6-dihydro-2,2′-anhydro-1-β-D-arabinofuranosyl-5-azacytosine hydrochloride 3 . The hydrolysis of 3 with EtOH/HCl at 25°C gave 2,2′-anhydro-5,6-dihydro-1-β-D-arabinofuranosyl-5-azacytosine hydrochloride 4 . Silylation oxidation of 3 and 4 with BSTFA or BSA in acetonitrile produced the N-substituted derivatives of 1-β-D-arabinofuranosyl-5-azacytosine 8 and 7 , respectively.     

非达司他中间体的酶法拆分

(2S)-6-氟-3,4-二氢-4-氧代-2H-1-苯并吡喃-2-羧酸是合成非达司他(一种口服醛糖还原酶抑制剂)关键中间体。该研究使用脂肪酶Novozym 435,对(±)-6-氟-3,4-二氢-4-氧代-2H-1-苯并吡喃-2-羧酸甲酯进行拆分,并对拆分反应条件进行了优化,确定了拆分的最适反应条件:乙腈-水溶液为溶剂,V(水)∶V(乙腈)=1∶4,m(酶)∶m(底物)=1∶10,在pH=7.0,温度40℃,时间为6 h条件下,得到的(2S)-6-氟-3,4-二氢-4-氧代-2H-1-苯并吡喃-2-羧酸的总收率为32.5%,对映体过量值为92.1%,为非达司他的制备提供了一条可行途径。     

Properties of ink‐jet printed,ultraviolet‐cured pigment prints in comparison with screen‐printed,thermo‐cured pigment prints

A collection of printed fabrics for men’s shirts was designed and prepared using computer‐aided design/computer‐aided manufacturing technology. The colours for designs were ink‐jet printed on cotton fabrics with pigments and ultraviolet‐cured. These prints represented the target colours for subsequent flat‐screen printing, which was performed using pigment printing pastes and thermal curing. For an exact transfer of colours of the ink‐jet‐printed standard into the screen‐printing process, a computer recipe prediction method was used. A comparison of colorimetric parameters of fabrics printed with both printing techniques shows minimal and acceptable differences in the CIELab colour values. A comparison of colour fastness properties proves that very good colour fastness is achieved on the pigment‐printed fabrics produced with both printing techniques. The flat‐screen‐printed fabrics show better colour fastness to washing, perspiration and rubbing, while ink‐jet‐printed fabrics show better colour fastness to dry‐cleaning and light. The fabrics printed with both printing techniques have high rigidity and non‐elastic properties. The mechanical and physical parameters are strongly dependent upon the amount of the dry substance of the printing media applied on the cotton fabric surface, which is higher on screen‐printed fabrics. The ink‐jet‐printed fabrics show better air permeability than flat‐screen‐printed fabrics.     

Experimental and theoretical study of the effect of some heterocyclic compounds on the corrosion of low carbon steel in 3.5% NaCl medium

The efficiency of three heterocyclic compounds, 3-amino-1,2,4-triazole, 4-hydroxy-2H-1-benzopyran-2-one and 4-hydroxy-3-(1H-1,2,4-triazole-3-ylazo)-2H-1-benzopyran-2-one (abbreviated 3-ATA, 4-HQ and 3-ATA-Q, respectively) as steel corrosion inhibitors in 3.5% NaCl has been investigated by Tafel extrapolation and linear polarization methods. Corrosion parameters and adsorption isotherms were determined from current-potential curves. It was found that inhibition efficiencies (η%) and surface coverage (θ) increase with an increase in the concentration of 3-ATA and 3-ATA-Q. However, 4-HQ accelerates the corrosion rate as its concentration increases. The adsorption of 3-ATA and 3-ATA-Q on the steel surface obey Langmuir isotherm. A clear correlation was found between corrosion inhibition efficiency and theoretical parameters obtained by the density functional B3LYP/6-31g(d) method. The experimental results are supported by the theoretical data.     

Digital and conventional printing and dyeing with the natural dye annatto: optimisation and standardisation processes to meet future demands

The plant colorant annatto was investigated to determine its potential use as a natural dye for conventional and novel textile applications. Alum was selected as a mordant. Different techniques of mordanting and a broad set of variations in the dyeing recipes were applied to achieve optimisation and an improvement in colour fastness properties. Quality control of all dyeings was performed using standard fastness tests and colour measurements. Printing of cotton fabrics was also achieved with annatto using the flatbed screen‐printing technique. Measurement of the rheological and physical properties of the annatto printing paste confirmed its stability and suitability for conventional printing. Fastness properties of the conventionally printed annatto fabric were also measured. A novel water‐based digital printing ink using annatto was prepared and applied to cotton fabric using a digital printing application. The physical properties of the annatto ink‐jet ink were also measured. Wash, light and rub fastness properties of the annatto digitally printed fabric were determined and compared with those of conventional printing methods. The results were promising for annatto as a natural colorant, which possibly paves the way for the development of a new range of natural environmentally friendly dyes.     

Colour matching for smart and sustainable spinning of coloured textiles

The colours and patterns of coloured textiles are usually obtained via dyeing or printing processes. However, these processes consume large amounts of electricity and cause water pollution, which affects the ecological environment. The hand feel of dyed fabrics is superior to that of printed fabrics. Three‐channel rotor spinning is a highly flexible, adaptable and sustainable method for producing coloured textiles by blending precoloured fibres during the spinning process. Additionally, the process requires approximately half the water required for fabric dyeing or printing. Herein, the colour characteristics, as well as the advantages, of the coloured textiles produced by the new method are demonstrated. Three types of Stearns‐Noechel models are modified to describe the relationship between the blending ratios and resulting textile colours. The colour‐matching accuracy is high. As demonstrated by the results, the three‐channel rotor spinning method can effectively promote coloured textile engineering.     

Fluorescent products of lipid peroxidation: I. Structural requirement for fluorescence in conjugated schiff bases

The structural requirement for fluorescence in Schiff bases was defined. Aldehydes and amines were reacted and the structures of the Schiff bases N-hydroxyethyl-1-imino-2′,4′-hexadiene (I), N-1-benzal-2-hydroxyaminoethane (II), and N-1-benzal-2,2′-hydroxyaminoethane (III) were established by elemental analysis, IR spectral analysis and mass spectral analysis. The structures of N-alanyl-2-hydroxy-naphthylidine (IV) and N,N′-dileucinyl-1-amino-3-iminopropene (V) had been established previously. III, IV and V were fluorescent compounds and I and II were not. The results of these analyses suggest that an electron donating group in conjugation with an imine is the structure required for fluorescence.     

双缩合螺吡喃的制备与晶体结构

通过过量Fischer碱与3,5-二氯水杨醛反应,得到了一种新型的双缩合螺吡喃(1),即4-(2-亚甲基-1-乙基-3,3-二甲基吲哚啉-2′-基)-6,8-二氯-1′-乙基-3′,3′-二甲基-螺[3,4-二氢-2 H-l-苯并吡喃-2,2′-吲哚啉],并通过熔点、元素分析、IR和X-单晶衍射仪进行表征,确定了该化合物的结构。结果表明:a属单斜晶系,空间群P21/n,晶胞参数a=1.2889(3),b=1.2395(3),c=1.9362(4)nm,β=106.86(3)°,V=2.9603(13)nm3,Z=4,F(000)=1160,Dc=1.228g/cm3,μ=0.247mm-1。