Textile applications of commercial photochromic dyes: part 7. A statistical investigation of the influence of photochromic dyes on the mechanical properties of thermoplastic fibres

The influence of the concentration of a commercial photochromic dye, incorporated into as-spun and drawn fibres produced from polyethylene and polypropylene, on their mechanical properties was investigated. As-spun fibres were produced by incorporating a commercial photochromic dye at different concentrations at the extrusion stage of the production process of polypropylene, polyethylene and polyester. The fibres from polypropylene and polyethylene, which showed photochromism when exposed to UV light, were then drawn, and their mechanical properties evaluated and analysed using a factorial experimental design, applying appropriate statistical methods. No further investigation was carried out on the polyester as the dye appeared to degrade at the higher temperatures required for its extrusion, leading to a brown fibre, which was not photochromic. According to the analyses, the most significant parameter influencing the mechanical properties of the as-spun fibres was the polymer type; the effect of the dye concentration was dominated by the significance of the polymer type. The effects of the multi-stage hot-drawing process used to produce the fibres on the mechanical properties of the drawn polypropylene and polyethylene fibres were characterised and statistically modelled. It was found that the dyeing concentration had a negative effect on the tenacity and the modulus of the drawn polypropylene fibres but a positive effect on the tenacity and the modulus of the drawn polyethylene fibres. A dye concentration of 0.2% on mass of polymer had a positive effect on the elongation of the drawn polypropylene and polyethylene fibres, whereas the higher dye concentration of 0.4% had a negative effect on the elongation of both drawn fibres. A new forecasting data source was obtained to optimise the selection of the polymer and the dye concentration and to specify the direction of modification, either increasing or decreasing, the significant process parameters.     

Fabrication of photochromic,hydrophobic, antibacterial,and ultraviolet-blocking cotton fabric using silica nanoparticles functionalized with a photochromic dye

The aim of this work was the fabrication of cotton fabric with multifunctional properties such as photochromic, hydrophobicity, antibacterial, and ultraviolet (UV) blocking. In this regard, a mixture of silica nanoparticles with spirooxazine as a photochromic dye first applied on the cotton fabric, and then, the fabric surface was coated with an alkylsilane compound. The homogenous distribution of silica and silica/spirooxazine hybrid on the cotton fibers was established by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray mapping. X-ray diffraction patterns confirmed the amorphous nature of the hybrid on the treated cotton fabric. The photochromic effect of the fabrics was measured after 5-min sunlight irradiation. Other characteristics of treated fabrics, such as antibacterial activity, hydrophobic properties, and UV-blocking activity, were also assessed. The results indicated that adding silica nanoparticles to spirooxazine had a tangible effect on photochromic activity of treated cotton fabrics and its photochromic performance was higher than that of the photochromic dye. The fabric showed stable hydrophobicity with static water contact angle values of 141.2° ± 1°. Moreover, the coated cotton fabric demonstrated proper antibacterial properties and UV-blocking activity.     

棉织物的螺吡喃微胶囊印花及其光致变色性能

为获得一种可检测紫外光强度的光致变色纺织品,采用溶剂挥发法制备以螺吡喃光致变色材料为芯材,以聚甲基丙烯酸甲酯为壁材的微胶囊,用微胶囊对棉织物进行丝网印花。表征了所制备微胶囊的粒径、形貌、芯材包封率及光致变色性能。采用自制变色梯度板记录微胶囊印花织物变色色差,探究了紫外光辐照条件对棉织物光致变色性能的影响和印花工艺对其耐摩擦色牢度的影响。结果表明:螺吡喃微胶囊的平均粒径为729 nm,分散指数为0.34;印花织物变色色差随微胶囊质量分数、紫外光强度及照射时间的提高而增加,微胶囊质量分数为14%的印花织物经30 W/m²紫外光照射100 s,变色色差可达19.02;印花织物的耐干、湿摩擦色牢度分别可达4~5级和4级,20次紫外-可见光循环照射后光致变色色差损失12.26%。     

Spectral and physical properties organo-silica coated photochromic poly-ethylene terephthalate (PET) fabrics

Abstract

In this study, photochromic fabrics were prepared by incorporating the spirooxazine derivative of 5-chloro-1,3-dyhydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]-naphth [2,1-b] [1,4] oxazine on the polyethylene terephthalate (PET) fabric through a sol-gel coating process. The treated fabrics showed good photochromic response under UV irradiation. In this work, three types of silane were used as the silica precursor and the resultant coatings showed a significant difference in their photochromic response such as Kubelka–Munk function (K/S), change in optical density (ΔOD) rate constant and half-life. The coated fabric shows two different absorption maxima and however it confirms that there is strong influence on the type of silane. The functional group of uncoated and sol-gel coated fabrics are analyzed by ATR-FTIR. The type of the silane also influences the physical properties of the coated fabrics. The surface characteristics were analyzed by scanning electron microscope (SEM) and laser scanning confocal microscope (LSCM), which showed significant changes in the surface micro-roughness after coating.     

Investigating the production and properties of Ag/TiO2/PP antibacterial nanocomposite filament yarns

In this research, investigating the possibility of producing, processing and also characterization of antibacterial organic/inorganic nanocomposite polypropylene fiber has been presented. For this purpose, PP powder and inorganic nanocomposite filler were mixed using a twin screw extruder and modified granule was produced. After producing as-spun filament yarns by a pilot plant melt spinning machine at the take-up speed of 2000 m/min, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated. The experimental results revealed that the crystallinity reduction of modified as-spun yarns could be compensated by drawing process. Tensile properties of modified drawn yarns with the variable draw ratio were higher than the pure PP, whereas the inverse observation was noticed in the case of constant draw ratio. The investigation of antimicrobial activity showed a high percentage of biostatic efficiency on the modified samples.     

Effect of blending two fiber-grade polypropylenes with different molecular weight distributions on the physical and structural properties of melt-spun filament yarns

In this study, the structural and physical properties of polypropylene fibers produced from the blending of two types of polymers having similar melt flow index but different molecular weight distributions (MWD) were investigated. Polypropylene with broad MWD (V30S grade) was blended with polypropylene with narrow MWD (511P grade) in various fractions (from 0% to 100%) to produce melt-spun filaments. Although the fraction of 511P in blends is higher than 25%, the blending is effective. Increasing the fraction of 511P in the blend increases tenacity and decreases breaking elongation. Mechanical properties of drawn yarns show the same trend as those of as-spun yarns with the blend composition. For as-spun yarns, addition of 10% of 511P polymer increases birefringence in comparison with the V30S yarn. There is little or no effect of blend composition on the development of crystallinity. Drawing increased the birefringence and crystallinity of as-spun filament yarns, but the values of increase are different for the samples.     

Effect of drawing ratio on difference in optical density and mechanical properties of mass colored photochromic polypropylene filaments

Photochromic textiles have been used in the sensible materials (sensor) in the smart textiles and esthetic materials in the fashion industry due to the color changing properties, which gives immense inspiration to prepare photochromic textile materials, in this regards we take more attention to prepare the mass dyed polypropylene filaments with photochromic pigments. Metallocene polypropylene filaments were doped by different concentration of photochromic pigment. In our experimental work, the optical and mechanical properties of these multifilaments depending on their drawing ratio were investigated. The photochromic pigment used was 5-Chloro-13-dihydro-133-trimethylspiro[2H-indole-23′-(3H)naphtha [2,1b](14)oxazine]. Regarding the optical properties, our investigation confirms the known effect of the primary reflectance on the depth of shade of colored multifilaments as shown by linear increase in difference in optical density with increasing ratio of fineness.     

羊毛的紫外线预处理染色工艺研究

由于毛用活性染料利用率不像酸性染料那样高,为了提高染料利用率,本研究采用自行设计的紫外线辐射装置对羊毛织物进行紫外线照射处理,照射功率和照射时间都进行了分组。研究了不同条件紫外线辐射处理对羊毛染色性能的影响,测试并分析了处理后羊毛的上染率、色牢度和强力变化,最后使用正交实验得出紫外线处理染色的最优条件。最佳照射功率为60W、照射时间15min、染料利用率达90%。     

Influence of Enzymatic Pretreatment on the Colours of Bleached and Dyed Flax Fibres

SUMMARY

In this paper the effect of enzymatic bioscouring on the bleaching and dyeing of flax fibres was studied in comparison with conventional alkaline scouring. Enzymatic bioscouring was performed with a commercial multi-enzyme system consisting of pectinases, hemicellulases and cellulases. The enzyme and alkaline scoured flax fibres were subsequently oxidatively bleached with hydrogen peroxide and dyed with direct dye C.I. Direct Red 80 under the same conditions. The efficiency of both the scouring and bleaching processes was evaluated by weight loss and the whiteness of the bleached samples was determined according to CIE formula. The exhaustion profile of the used dye was followed on-line during the dyeing process using absorbance measurement. The colours of bleached and dyed samples were evaluated using CIELAB colour values. The residual pretreatment and dyeing baths were ecologically analysed with COD, TOC and BOD₅. The obtained results indicate that enzymatic scouring provides a lower weight loss, a higher degree of whiteness, comparable dyeing properties and is more environmentally friendly.     

光致变色纺织品的检测方法

针对光致变色纺织品变色性能检测方法缺失的问题,以商品化的光致变色纺织品为研究对象,通过模拟光致激发环境,采用手持式分光测色仪测量样品的颜色变化,研究光致变色纺织品的变色和恢复机制,建立光致变色纺织品的检测方法。结果表明:受光照射后样品颜色变化呈先深后浅趋势,并在照射3 min左右达到稳定;太阳光辐照度不会影响样品的变色与恢复过程,采用AM1.5滤光片,辐照度为1 000 W/m ²的标准太阳光作为激发光源照射样品5 min,并遮光恢复30 min,分别使用人眼和仪器评级测定样品的变色和恢复色差,均可有效检测光致变色纺织品的变色性能;该检测方法简单易操作,可靠性强,可标准化。     

The effect of the acid/dithionite/peroxide treatments on reactively dyed cotton and indigo dyed denim and the implications for waste cellulosic recycling

Abstract

Previous studies have established that the application of crosslinking dyes and easy care finishes to cotton can significantly reduce the dissolution of waste cotton in swelling solvents and limit potential recycling of cellulosic materials through Lyocell fibre regeneration process. In this study, a sequential hydrolysis/reduction/oxidative treatment was investigated as a potential method to completely strip all types of reactive dye chromophores from cotton. It was established that the treatment could completely strip off colours from the reactively dyed fabrics and post-consumer denim jeans fabric resulting in a white, NMMO-dissolvable cellulosic material, which could be used as a feedstock for Lyocell fibre regeneration. The white cellulose had an acceptable degree of polymerisation and the regenerated fibres had structural and mechanical properties similar to those of fibres regenerated from conventional wood pulp. Blending conventional wood pulp and recycled cotton pulp allowed manufacturing of regenerated Lyocell-type fibres with acceptable properties.     

纳米氧化钨复合棉纤维的制备及其光致变色性能

针对氧化钨晶相结构不稳定,光变色响应时间长,寿命短等问题,先采用水热一步法制备浅黄色氧化钨纳米棒,再通过磁力搅拌将其均匀分散到聚乙烯醇溶液中,最后采用快速连续的浸渍涂覆工艺在棉纤维表面涂覆氧化钨纳米棒,制备光致变色纤维,并对其结构和性能进行表征。研究结果表明:光致变色纤维在紫外光照射下,在1 min 内颜色由最初的淡黄色变为灰蓝色,并在5 min内逐渐变为深蓝色;在红外灯加热处理过程中,纤维的颜色在约2 h内恢复到其初始状态,表现出从浅黄色到深蓝色的快速、可逆的颜色切换。该光致变色纤维可规模化生产,可编织成各种图案,在开发光致变色纺织品方面具有很大的潜力。     

Determining the spectral transmittance of photochromic contact lenses

PurposeThis study evaluates the spectral transmission of photochromic contact lenses.MethodA custom built photochromic filter transmission testing device (ICS photochromic bench) was developed to measure the spectral transmission of light adaptive filters. The spectral properties of seven contact lenses were measured using the ICS photochromic bench at 23⁰C and 35⁰C in their exposed (darkening) state at time points 0 s, 45 s, 90 s, and 15 min. and their unexposed (fading) state at 45 s, 15 min. and 20 min.. Mixed between and within repeated measures ANOVA (MRM-ANOVAs) and generalized additive modeling (GAMs) were used to compare the effects of temperature and solar exposure time on spectral transmittance of photochromic contact lenses.ResultsThe mean (±SD) transmission of photochromic contact lenses in the exposed state were 94.7 ± 0.2, 39.1 ± 1.4, 27.0 ± 0.7 and 14.7 ± 1.0, and 93.7 ± 0.9, 38.8 ± 2.4, 30.2 ± 1.8, and 26.1 ± 1.0 at times 0 s, 45 s, 90 s, and 15 min. at 23⁰C and 35⁰C respectively. The mean (±SD) transmission of photochromic contact lenses in the unexposed state were 18.3 ± 1.5, 71.3 ± 2.4, and 80.2 ± 2.4, and 39.1 ± 1.0, 90.6 ± 1.0 and 91.1 ± 0.9 at times 45 s, 15 min. and 20 min. at 23⁰C and 35⁰C respectively. There was a significant decrease in light transmission as solar exposure time increased (GAM, MRM-ANOVA, p < 0.05). There was a significant effect of temperature and solar exposure time on the photochromic contact lenses (GAM, MRM-ANOVA, p < 0.05). The differences in the light transmitted by the photochromic contact lenses occurred at time 90 s and 15 min (Tukey HSD, at 90 s and 15 min, p < 0.05), where contact lenses at a temperature of 35⁰C showed greater light transmission than that at 23⁰C. There were differences in spectral transmittance based on the temperature of the contact lens. Contact lenses at 35⁰C transmitted more light than at 23⁰C at all unexposed times (MRM-ANOVA, p < 0.05).ConclusionSpectral transmission of photochromic contact lenses were successfully measured with the ICS photochromic bench. Temperature appears to influence both the activation and deactivation of photochromic contact lenses such that the higher the temperature, the greater the light transmission.     

A contra-lateral comparison of the visual effects of a photochromic vs. non-photochromic contact lens

PurposeTo compare the effects of a photochromic contact lens vs. a non-photochromic control lens on visual function.MethodsA subject-masked, prospective contralateral eye design was used. Sixty-one subjects were enroled based on age (using a 2:1 allocation ratio for ages 18–39 and 40–65 years, respectively). The study lenses were senofilcon A with photochromic additive (Test) that filtered over the entire lens, compared to a non-photochromic Control with no tint. The Test lens was partially activated during testing with a steady-state transmittance of approximately 62%. Eligible subjects were tested using both study lenses, with Test and Control lens randomized by eye. Five visual function outcomes were tested: photostress recovery (PSR), glare disability (GD), glare discomfort (GDC), chromatic contrast (CC) and vernier acuity (VA). Iris colour and macular pigment density were assessed as control variables. PSR was measured as the time needed to recover sight of a target after an intense xenon flash exposure; GD was evaluated as the energy needed to veil a central target by a surrounding xenon annulus; GDC was measured using bio-imaging of the squint response and by self-report using a 9-item Likert scale; CC was measured as thresholds for a yellow grating target superposed on a 460-nm background; VA was determined by measuring vernier offsets of light lines through apertures.ResultsBased on our stimulus conditions, PSR was 43% faster using the Test vs. the Control. The eye wearing the Test had 38% less squint (GDC) compared to the Control. GD was improved by 36% in the Test vs. Control and CC was enhanced by 48% with the Test. There was no significant difference in VA.ConclusionsThere was a beneficial influence on visual function when comparing the photochromic with the non-photochromic contact lens. This benefit was seen specifically with respect to PRT, GDC, GD and CC thresholds.     

The use of natural Areca catechu dyes for silk and nylon and its halochromic effect

Abstract

In this study, we have investigated the use of betel nut (Areca catechu) extract solution as a natural dye for the use of dyeing for silk and nylon. Chemical structure of betel nut extracted solution was confirmed by using FTIR and ¹H NMR spectroscopy and thermal properties also measured for determining the proper dyeing temperature. In order to optimise the colouration properties, variable dyeing parameters (temp, pH and mordant type) was studied. The halochromic effect of synthesised natural dye was analysed by using UV–Vis spectroscopy. Additionally dye build-up, colour fastness properties of both fabrics were compared.     

Use of smart photochromic indicator for dynamic monitoring of the shelf life of chilled chicken based products

This study evaluated the applicability of a photochromic time temperature indicator (TTI) to monitor the time–temperature history and shelf life of chilled boneless chicken breast. The results showed that the smart indicator showed good reproducibility during the discoloring process in all the conditions investigated. The response was not only visibly interpretable but also well adaptable to measurement using appropriate equipment. For an activation configuration of 4 s of ultraviolet light (UV) per label, the TTI's rate of discoloration was similar to the quality loss of the meat samples analyzed. Thus, the photochromic label (4 s UV/label) attached to the samples set out to be a dynamic shelf-life label, assuring consumers the final point of quality of chilled boneless chicken breast in an easy and precise form, providing a reliable tool to monitor the supply chain of this product.     

Low temperature dyeing of wool fabric by acid dye after UV irradiation

The aim of the work was to improve wool’s dyeability using acid dye through a simple pretreatment with ultraviolet (UV) irradiation. Different radiation doses were investigated using both a laboratory UV lamp and a semi-industrial apparatus. UV-treated fabrics were characterized in terms of morphological, chemical and physical properties by SEM, FTIR-ATR spectra, water contact angle measurements, bursting and pilling test. The pre-treated samples were then dyed with an acid dye at different dyeing temperatures to compare the results with the untreated fabric. Final bath exhaustion reached, kinetic curves and colour measurements were evaluated. Moreover, the colour levelness of the dyeings obtained on fabrics with and without irradiation was assessed. Finally, dyeing fastness to washing and rubbing were determined according to ISO standard methods.     

A novel photochromic time–temperature indicator to support cold chain management

A detailed investigation of the behaviour of a new printable photochromic time–temperature indicator (TTI) was conducted to characterise its properties under specific temperature conditions and to analyse the influence of ultra violet (UV) light irradiation (activation) on the discolouration process. The reproducibility of the charging process and the discolouration process of the TTI were analysed. For different charging times the calculated activation energies based on the Arrhenius model ranged from 23.2 to 25.3 kcal mol^?1 depending on the UV light irradiation (charging time). A quality contour diagram was established to define the appropriate charging time for different kinds of products. Due to the possibility of defining the shelf life of a TTI by different charging times, this novel TTI constitutes a reliable tool to monitor the cold chains of a broad range of food products on their way from production to consumption.     

Transparent Photochromic Wood Composites Incorporating AgBr Nanoparticles for UV-shielding Applications

Transparent wood (TW) is a wood-based biomaterial with several advantages, such as high optical transmittance, low thermal conductivity, and tunable haze. TW is functionalized according to its transparency to broaden its applications in different fields. Several studies have examined wood functionalization in recent years; however, few studies have reported photochromic TW (PTW) for ultraviolet (UV) -shielding window applications. Herein, PTW was obtained by infiltrating the delignified wood template with photochromic silver bromide (AgBr) nanoparticles and a pre-polymerized methyl methacrylate (MMA) mixture solution. The obtained PTW can adjust the luminous flux on change in the color in the visible light region. The photochromic properties were examined, and the optical properties of the composites were characterized using UV-Vis spectrophotometry. Light transmittance of PTW was up to 86.5% at 800 nm before UV irradiation, and it decreased to 70.1% at 800 nm after UV irradiation, as the wood color changed from colorless to dark purple under UV irradiation. Thus, this work not only achieves high-value utilization of wood, but also produces a new material that can be used in varied fields, such as UV-shielding, energy saving, and smart building.     

分散染料的纳米TiO_2光催化脱色

以低压紫外汞灯为光源,纳米材料为光催化剂,探讨不同类型纳米粉体对水溶液中分散染料的光催化脱色特性。结果表明,N掺杂TiO2纳米光催化剂和TiO2酸性分散液的光催化脱色效果较佳;溶液pH值、催化剂用量、光催化时间对分散染料溶液的脱色率有较大的影响;H2O2、Al3+和Fe2+的加入,有助于提高光催化脱色率;杂环、杂环偶氮类和偶氮苯类结构的分散染料均比蒽醌类容易被光催化降解脱色,染料中所含的取代基对其光催化脱色性能有重要影响。