No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Colouring plastics: fundamentals and trends
Abstract
Colour masterbatches, or colour concentrates, find applications in many areas of plastics processing. Blow, injection and rotational moulding, extrusion, calendering, and wire and cable manufacturing all depend on them.The masterbatches contain a high loading of colourants, also known as pigments or dyes, in a carrier resin. Richard Abrams, Mir Ali, Paul Denton, Juan Igualada, Martin Groen and Eddy Gschwind of Ferro present an overview of the subject of colour with a view to understanding the complex tasks that colour engineers face.
... There are three ways of polymers coloring: with dry pigments, with liquid colors and concentrates. The color management of the polymer is carried out according to the color of the finished product by exposing the pigment at the polymer components premixing step[4]. For working with thermoplastic materials, mistakes in the formation of the material color will bring recyclable waste, whereas thermosetting plastics-non-recyclable one. ...
... However, the dosing of some components of the pigment with subsequent addition to the polymer is offered there. While in[2,4]the possibility of coloring polymers and the effect of the coloring medium concentration in it on the functional characteristics of the material is described, the color management process and the evaluation of the thermosetting plastics color quality are not considered. It should be noted that most of the studies considered do not offer the solution of the problem of selecting color-forming components to form a given color, moreover, they do not describe the methods of prompt evaluation of their suitability. ...
The diagnostics of the color formation systems of thermosetting plastics LasilCast4, Synthene PR 403, Synthene PR 2000 was carried out. The process of selection the concentrations of coloring media for coloring thermosetting plastics in bulk is considered. An approach for improving the coloring of polymers using colour management systems based on the use of subtractive coloring media (CMY + K) is proposed. The cause-effect relationships of the influence of colorimetric parameters of pigment pastes on the process of polymers coloring were established. To describe the reproducible colors, it is proposed to construct a body of color gamut based on the data on the color-forming components. The results of the color gamut of the multicomponent polyurethane color formation system using viscous pigment pastes are presented. The technique of diagnostics coloring systems for polymers-thermosetting plastics is proposed, which provides visual clarity and high accuracy in predicting color reproduction during polymer coloring. The accuracy is confirmed by the experimental data and the calculated values of the color difference. It is shown that the system of color formation on the basis of the Synthene PR 403 polymer has the broadest color gamut.
... Color disparities concerning goal values in terms of dL*, da*, and db* are utilized rather than absolute values of color. In CIELAB space of color the total change, dE*, is used to represent color differences [5]. ...
Incorporating pigments into polymers can be done for various purposes, including the introduction of color, interfacial effects, or aesthetics. If these pigments are to disperse properly, then the process of extrusion must be optimized. During polymer compounding extrusion, three effective processing factors were investigated: feed rate (FR), speed (Sp.) and temperature (temp.) for a colored compounded polycarbonate (PC) grade (30/70%). The processing design techniques were obtained by applying design experiments in a response surface methodology (RSM) to blend two polycarbonates with pigments and optimize the processing temperatures at center points. The first study decided to utilize the response surface approach of Box–Behnken design (BBD) to design an experiment to optimize the process parameters. Statistical significance was demonstrated by the model passing all diagnostic tests. Furthermore, the three processing factors strongly impacted the characteristics of the tri-stimulus color, according to the results from a variance analysis. The second study identified process variables for the same PC grade at the center level, 25 kg/h FR, 750 rpm speed, and (255 °C) temp. The characterization and scanning morphology were examined using MicroCtscanner image analysis, SEM, DOM, rheology, FT-IR, and color-pigmented values were measured using a color spectrometer. The output response was significantly impacted when excellent color dispersion was observed with few agglomerates and less differences in colors at the center point. By characterizing these results and having good insight into color difference output and processing condition relationships, which have an adverse effect on color variation characteristics and minimize recycling compounds of different grades, results in cleaner environments benefits.
... Processing circumstances or certain combinations of modifiers and additives in the resin system were shown to have a negative impact on the final desired hue [12,13]. Paints and coatings have had a lot of research done on pigment dispersion, but plastics have not gotten nearly as much attention [14,15]. ...
The processing parameters’ impact such as temperature (Temp.), feed rate (F.R.), and speed (S.) at three distinct grades of the same color was explored in this study. To investigate the effect of the characteristics on color formulations, they were each adjusted to five different levels. For these grades, which were all associated with the same color, an intermeshing twin-screw extruder (TSE) was used. The compounded materials were molded into flat coupons then evaluated with a spectrophotometer for their CIE (L*, a*, b*, and dE*) values. A spectrophotometer was used to determine the color of a compounded plastic batch, which measured three numbers indicating the tristimulus values (CIE L*a*b*). The lightness axis, which ranged from 0 (black) to 100 (white), is known as the L*-axis (white). Redness-greenness and yellowness-blueness were represented by the other two coordinates, a* and b*, respectively. The color difference deviation (Delta E*) from a target was dimensionless, when dE* approached zero. However, the most excellent favorable color difference value occurred and different processing impact factors on polycarbonate grade were investigated. Using the response service design (RSD) software of Stat-Ease Design-Expert® (Minneapolis, MN, USA), historical data were gathered and evaluated. To reduce the value of dE*, the impacts of these processing factors were investigated with the three processing parameters. The whole tristimulus color value could be simulated. Parameters were adjusted on 45 different treatments, using a five-level controlled response method to investigate their impact on color and detect non-optimal responses. The ANOVA for each grade was used to build the predicted regression models. The significant processing parameters were subjected to experimental running to simulate the regression models and achieve the best color, reducing waste.
... In recent times, use of colorant on plastic products have become a trendy way of life. They are attractive and are used to create certain distinction as well as improving usability and quality with great risk to health [41]. ...
The persistent nature of single use plastics has become a cause for major health and environmental concerns worldwide as a result of commercialization. Africa as a continent generates considerable amounts of single use plastic wastes from the total plastic wastes generated. The prolonged use and mismanagement of existing wastes poses environmental and public health risks. Current practices involve managing single use plastic wastes in combination with other municipal and medical wastes. As many countries in Africa have put into law some legislation on the use of single use plastics, the level of enforcement and implementation is questionable provided that no tangible measures have been put in practice. This is evidenced by the ever-present single use plastics strewn around. Although infrastructural and skill-related challenges are pertinent to the management of single use plastics across the continent, single use plastic waste reduction, community-based indigenous model practices which are cost effective should be encouraged. This waste reduction and recycling practice in the long run make a positive impact on people’s lives by achieving sustainable development goals.
... Interest in special-effect pigments has increased in recent years [3][4][5][6]. These pigments offer attractive visual features, such as changes in color and lightness of finishes with viewing and illumination direction (goniochromatism). ...
In our society, objects’ visual appearance is an essential factor because it allows us to recognize and differentiate one object from another. In different industrial sectors like cosmetics, textiles and automotive, special-effect pigments are largely used to achieve attractive visual features. These pigments provide a color change with viewing and illumination direction, and visually provide texture. Depending on a finish’s properties, and also on the viewing and illumination conditions, coatings exhibit sparkle or a graininess-like texture. Currently, not many scientific works on the visual perception of these texture effects can be found in the literature. In addition, choice of experimental method can influence the measurement scale obtained from visual data. For this reason, the purpose of this work was to analyze graininess visual scaling constructed by two different psychophysical methods. The experimental design was based on the rank-order and paired-comparison methods. The data analysis was conducted by following the law of comparative judgments to obtain a visual scale of the graininess attribute to compare it to instrumental data. A good correlation appeared between both magnitudes with a correlation coefficient close to 0.9. Both methods provided useful results with a reasonable correspondence between them, which ensures that data can be considered reliable, while the visual obtained scale can act as a good graininess scale perceived by the human visual system.
... During the past century, the use of goniochromatic or special-effect pigments 1,2 has exponentially grown in many modern industries, from the automotive sector, 3,4 as a pioneer user of these pigments, to others (coatings, cosmetics, dentistry, 5 plastics, 6 printing, 7-9 textiles, 10 etc). In the last several years, different color-measuring instruments, multiangle spectrophotometers, were developed to measure and characterize special-effect pigments (metallic, interference, pearlescent) used in many materials to create a particular visual appearance. ...
Several different instruments have been introduced into the market to obtain good color characterization for different measurement configurations. These commercial instruments have different optical and working configurations, however, the measurement data provided by each instrument should be similar to have good consistency when comparing them to each other measuring the same sample material. Therefore, the purpose of this work was to apply an inter‐model agreement study of spectral and colorimetric data of three instruments (CM‐M6, BYK‐mac‐I, and MA98). Two different statistical tests were applied following ASTM recommendations. In general, the measurement geometries close to the specular direction and the flop direction showed greater deviations. In addition, the partial color differences calculated for the comparison of MA98 versus CM‐M6 were larger than the BYK‐mac‐i versus CM‐M6 comparison. Finally, it can be concluded that most of the measurement geometries were statistically significantly different from each other which means that these differences were due to systematic or bias errors and not exclusively to random errors.
... Unfortunately, in certain color spaces, such as the RGB color space, this color difference is not proportional with human visual sensation. Therefore, in most of the industrial applications where it is important to have color differences which are mainly proportional to human sensation the CIELAB color system is used [12]. Pisciotti et al. [13] has measured the effects of injection molding parameters on color and gloss in case of PP parts, and has concluded that mold temperature and packing pressure have a significant effect on the measured color and gloss. ...
In this paper we are presenting a novel method for color inhomogeneity evaluation. We proved that this method has a higher than 95 % linear correlation coefficient if results are correlated with human visual evaluations.We applied this evaluation method to analyze the homogenization in the injection molding process, therefore we measured the homogenization properties of various solid phase masterbatches on injection molded parts. We tested the effects of the processing parameters of injection molding and analyzed various dynamic and static mixers as well. We have also measured the influence of the mold surface texture on the sensation of inhomogeneities on the part surface.We have carried out our tests on an injection grade ABS material using various masterbatches. The method was based on the digitization of the molded flat specimens. The images of these specimens were evaluated with an own developed formula using the CIELAB color space resulting high correlation with human visual inspections.
... Titanium dioxide is commonly used in various plastic polymers as a non-toxic pigment, filler, or UV blocker owing to its excellent durability, opacity and resistance to chemical, and UV degradation (IARC, 2010). Also, phthalocyanine is a synthetic pigment that has extensive applications in the plastic industry (Charvat, 2005). A strong Raman signal derived from the plastic additives could mask the Raman spectra of plastic polymers (Van Cauwenberghe and Janssen, 2014). ...
... The evaluation algorithm used the CIE Lab color coordinates ( [ , , ]), since it is device-independent [20][21][22] and approximates human color difference sensation well [23]. The algorithm scans the image with a given window size and at every ( , ) position of this window the mean color coordinates are calculated ( , , ), where is the size of the window. ...
Appearance is a key factor in most injection molding applications. Unfortunately, there is no widespread method to objectively test visual appearance, such as color inhomogeneity of the parts or other surface defects. We developed an evaluation method to characterize the color inhomogeneity of injection molded parts. First, we examined manufacturing conditions and masterbatch recipes and then the individual effects of the components and their interactions on homogeneity.
... [273] Organische Farbstoffe bieten hierbei im Gegensatz zu Pigmentpartikeln den Vorteil von Transparenz und hoher Farbstärke, wohingegen anorganische Pigmente deutlich kostengünstiger sind. [274,275] [129] Abbildung 7.19: Lichtmikroskopische Aufnahmen von PP/C 1 C 18 ImOTs/E133-0.11 (links) und von PP/PEHO-C 18 ImOTs/E133-0.11 ...
Im Mittelpunkt der vorliegenden Arbeit stehen nanostrukturierte polyionische Flüssigkeiten (PILs) auf Basis von hyperverzweigtem Poly(3-ethyl-3-hydroxymethyloxetan) (PEHO). Diese PILs mit zwiebelartiger Topologie bestehen aus einem kompakten Polyoxetan-Kern, einer polaren inneren Schale aus polymergebundenen Imidazolium-Kationen und niedermolekularen Anionen sowie einer unpolaren äußeren Schale aus Alkylketten. Ein Ziel dieser Arbeit war die Synthese und Charakterisierung einiger bereits bekannter sowie zahlreicher neuer Mitglieder dieser Familie hyperverzweigter Polyelektrolyte. Ein weiteres Thema bestand in der Evaluierung neuer Anwendungen dieser PILs, wobei der Fokus auf der mit einer ausgeprägten äußeren Octadecylschale ausgestatteten PIL ruhte. Ein weiteres Ziel der Arbeit bestand in der Herstellung neuartiger Hybridmaterialien aus funktionalisiertem Graphen (FG) mit aufgepfropften hyperverzweigten PILs.
Mittels kationischer Polymerisation wurde hyperverzweigtes PEHO mit Molmassen von 2000-2500 g/mol und hohen Verzweigungsgraden von bis zu 51% erhalten. Durch Tosylierung der OH-Gruppen wurde tosyliertes PEHO hergestellt, welches als Edukt für weitere Funktionalisierungen diente. Ausgehend von tosyliertem PEHO konnten zwei interessante, bislang unbekannte neutrale PEHO-Derivate hergestellt werden: das mit NH2-Gruppen dekorierte PEHO-Amin und das mit ungeladenen Imidazolringen ausgestattete PEHO-Imidazol.
Sowohl das tosylierte PEHO als auch das Imidazol-funktionalisierte PEHO wurden als Ausgangsmaterialien zur Synthese diverser nanostrukturierter PILs eingesetzt. Neben den bereits bekannten PEHO-Alkylimidazolium-Tosylaten mit äußerer Schale aus Methyl-, n-Butyl- und n-Octadecylresten wurden verschiedene neue PILs hergestellt, wodurch die Produktpalette dieser hyperverzweigten Polyelektrolyte enorm erweitert werden konnte. So wurden erstmals PEHO-Imidazolium-PILs mit ungesättigten Allyl- und Propargylresten, mit magnetischen FeCl4-Anionen und mit protischen Imidazoliumringen synthetisiert. Die Umsetzung von PEHO-Imidazol mit Polyethylenglykol-Ditosylat bewirkte eine Vernetzung, wodurch neuartige kovalente polyionische Netzwerke erhalten wurden, die sich durch eine starke und reversible Quellbarkeit in Wasser auszeichneten. Weiterhin wurde ein neues PEHO-Polyanion mit einer Schale aus Natriumbenzolsulfonat-Gruppen hergestellt.
Die Untersuchung potentieller Anwendungen des PEHO-Octadecylimidazolium-Tosylats offenbarte zahlreiche und vielseitige neue Einsatzmöglichkeiten dieser mizellartigen PIL als Nanotransporter und Dispergiermittel. Transportexperimente zeigten, dass sich die amphiphile PIL nicht nur zum Phasentransfer hydrophiler Moleküle, sondern auch zum Transport und zur Solubilisierung von Nanopartikeln einschließlich FG-Nanoplättchen in unpolaren Lösungsmitteln einsetzen lässt. Zudem erwies sich diese PIL aufgrund der organophilen n-Octadecylketten als hochkompatibles Additiv für unpolare Polyolefine. Durch Einarbeitung in Polypropylen und ein Ethen-Octen Copolymer mittels Schmelzextrusion wurden PIL-Polyolefin-Blends erhalten, in denen die hyperverzweigte PIL in Form von Nanophasen dispergiert ist. Diese Nanokompartimente ermöglichten eine Solubilisierung hydrophiler Farbstoffe, wodurch homogen und intensiv leuchtend gefärbte Materialien erhalten wurden. Dies offenbart die hervorragende Eignung der PEHO-Octadecylimidazolium-PIL zum Transport hydrophiler Moleküle in unpolaren Polymerschmelzen, wohingegen sich die analoge n-butylsubstituierte PIL und eine amphiphile niedermolekulare ionische Flüssigkeit als nur wenig effektiv erwiesen. Die amphiphile PIL konnte weiterhin vorteilhaft bei der Herstellung von Nanokompositen aus FG und Polystyrol (PS) eingesetzt werden. Verglichen mit den reinen FG-PS-Kompositen bewirkte die PIL eine deutlich gleichmäßigere Dispergierung des FG unter Ausbildung leitfähiger Netzwerke, woraus eine signifikante Steigerung der elektrischen Leitfähigkeit resultierte.
Ausgehend von FG mit aufgepfropftem hyperverzweigtem PEHO wurden neuartige Hybridmaterialien aus FG und kovalent angebundenen PEHO-Alkylimidazolium-PILs hergestellt. Mittels polymeranaloger Reaktionen wurden die aufpolymerisierten PEHO-Bäumchen mit Methylimidazolium- sowie Octadecylimidazolium-Tosylat-Gruppen ausgestattet. Die FG-PIL-Hybridmaterialien mit kovalent angebundener hydrophiler bzw. organophiler PIL zeigten eine ausgezeichnete Dispergierbarkeit in Wasser bzw. unpolaren Medien. Der Vergleich mit bloßen Mischungen aus FG und entsprechender hyperverzweigter PIL belegte den positiven Effekt der kovalenten Verknüpfung von FG und PIL auf die Dispersionsstabilität. Darüber hinaus zeichneten sich die neuen FG-PIL-Materialien durch das Vorliegen hauptsächlich einzelner FG-Nanoplättchen und die Fähigkeit zur Bildung dünner Filme mit flach orientierten Graphen-Schichten aus.
... Despite the chemical inertness of polyethylene, it is possible to provide coloration through the introduction of pigments during fiber formation when polyethylene is in a molten state. 50 On the other hand, nylon fibers can be colored easily using conventional dyes. 51 Depending on the pigment or dye, additional vibrational modes may be introduced in the IR wavelength range reducing the overall transparency. ...
Personal cooling technologies locally control the temperature of an individual rather than a large space, thus providing personal thermal comfort while supplementing cooling loads in thermally regulated environments. This can lead to significant energy and cost savings. In this study, a new approach to personal cooling was developed using an infrared-transparent visible-opaque fabric (ITVOF), which provides passive cooling via the transmission of thermal radiation emitted by the human body directly to the environment. Here, we present a conceptual framework to thermally and optically design an ITVOF. Using a heat transfer model, the fabric was found to require a minimum infrared (IR)
transmittance of 0.644 and a maximum IR reflectance of 0.2 to ensure thermal comfort at ambient temperatures as high as 26.1oC (79oF). To meet these requirements, an ITVOF design was developed using synthetic polymer fibers with an intrinsically low IR absorptance. These fibers were then structured to minimize IR reflection via weak Rayleigh scattering while maintaining visible opaqueness via strong Mie scattering. For a fabric composed of parallel-aligned polyethylene fibers, numerical finite element simulations predict 1 μm diameter fibers bundled into 30 μm yarns can achieve a total hemispherical IR transmittance of 0.972, which is nearly perfectly transparent to mid- and far-IR radiation. The visible wavelength properties of the ITVOF are comparable to conventional textiles ensuring opaqueness to the human eye. By providing personal cooling in a form amenabl to everyday use, ITVOF-based clothing offers a simple, low-cost solution to reduce energy consumption in HVAC systems.
... Usually, plastic color mismatch problems are solved ad-hoc by either experienced operators who have a feel for which pigment to add (due to experience) or based upon spectral analysis which indicates frequencies are lacking in the reflectance spectra and the pigments are adjusted accordingly in the new formulation [4]. Most research approaches in plastic compounding are experimental based and use methods such as Design of experiments, Tagushi method, Anova and other types of methods [5]. The use of data mining methods is becoming more common in the manufacturing industry [6]. ...
Nowadays, most manufacturing companies store their data electronically. The selection of the appropriate data mining algorithm for exploration of this data can quickly identify issues leading to process improvement and cost reduction. In this paper, The Decision Tree. Classifier (DTC) is used for plastic color mismatch parameters analysis. Especially, the relationship between polymer grade, color, type, line of production, and ingredients supplier is analyzed. DTC Results showed interesting and evident relationships between certain parameters.
The principal objective of incorporating pigments in the polymer is to introduce color either for aesthetic reasons or for the functional requirements. The enhancement of extrusion process parameters is necessary for the proper dispersion of pigment in the polymer. In the study presented three influential processing parameters during extrusion of polymer compound are speed, temperature and feed rate. The experimental design software with Box Behnken (BBD) methodology is being utilized for the optimization. The optimized model and experimental data exceeds the analytical examination making the formulation of model crucial. Also, it was found that the extrusion parameters have strong impact on color characteristics DL, Da and Db which is determined through the analysis of variance (ANOVA). Moreover, specific mechanical energy was calculated for the experimental runs and it was revealed that the specific energy decreases with increase in feed rate.
Implementation of material value conservation (MVC) needs to be proven through research to determine impact upon plastic properties such as optical properties of virgin plastic and recycled plastic blends. Optical properties such as colour, transparency and gloss are important parameters for appropriate quality of plastic packaging. Degradation of optical properties occurs during recycling processes of plastic materials and the declining properties of recycled products could be improved by blending them with virgin materials. This research aims to reveal the impact of repetitive recycling on optical properties of virgin and recycled polypropylene (PP) blends based on MVC paradigm. The first step of this research was to determine composition of virgin PP and recycled PP blends. Proportion of 70% virgin PP and 30% recycled PP was selected as a blend composition. The next step of this research was repetitive recycling of virgin PP and recycled PP blends with implementation of MVC up to the 8 th recycling stage. The specimens of plastic blends were made from the 1 st , 2 nd , 4 th and the 8 th recycling stage and then their optical properties were tested with the American Society for Testing Materials (ASTM) methods. Generally, degradation level of optical properties will increase during the recycling processes. Testing results show a slightly change of colour properties. Degradation level of gloss properties is gradually increased by a maximum degradation level at the 8 th recycling stage as 17.46%. However, transparency had a maximum degradation level at the 4 th recycling stage as 20.93%. It means that the plastic blends can be used as viable raw materials based on their optical properties with more attention to the gloss. Furthermore, the implementation of MVC will provide more benefits through extending the life cycle of recycled products, reducing virgin plastic consumption, optimizing the use of plastic waste and reducing plastic waste generation.
Microplastic pollution is a significant and growing environmental issue. Recent studies have evaluated the atmosphere as an important pathway of microplastic contamination. Airborne microplastics can be transported long distances and accumulate in various terrestrial and aquatic environmental matrices, where they represent a threat to the biosphere. This review systematically summarizes the existing knowledge on airborne microplastics, including the different sampling and analytical techniques, occurrence and sources. We investigate the different sample collection techniques from street dust to indoor and outdoor air and examined sample preparation, pre-treatment and characterization techniques. We further explored the key factors with respect to their occurrence in the environment such as concentration levels, polymer composition, size distribution, shape and colour characteristics. The sources of airborne microplastics were also summarized. The results show that microplastics are ubiquitous in all atmospheric compartments including street dust and indoor and outdoor air at various concentrations, which is influenced by the community’s lifestyle choices, anthropogenic activities and meteorological conditions. Various forms of microplastics including spherules, film, fragments, fibres and granules were identified with fibrous microplastics being the most dominant. Additionally, microplastics of 20 different polymers and varying colour characteristic have been reported in studies focusing on airborne microplastic contamination. The size distribution of microplastics varied among the studied air compartments; however, they were mostly distributed towards the smaller size ranges, less than 1 mm. Our review highlights a need to consider atmospheric pathways in addition to soil and water migration dispersion processes for any holistic assessments of microplastic threats to the biosphere. Moreover, standardization of airborne microplastic sampling methods is needed to optimize the effectiveness of future work in this area. Graphical AbstractMicroplastics in atmospheric environments Microplastics in atmospheric environments
Trace metallic elements (TMEs) are pollutants of great concern even in trace amounts because of their toxicity and cumulative property. Some of them can be carcinogenic. The Sfax metropolis, located in the southern region of Tunisia, has been affected by releases of TMEs for decades. Several studies confirmed that this pollution is predominantly originated from anthropogenic sources, mainly from industrial activities. It represents a threat to the health of residents, particularly for those also exposed during occupational activities in industrial processes. The present study aims to assess health risks associated with occupational exposure in industries handling TMEs in their production processes, following the human health risk assessment approach. To this end, five companies using raw material containing TMEs to produce a variety of metallic products accepted to participate to the study. The metals that were investigated are Al, Cr, Ni, Cu, Zn and Pb. Mathematical models for estimating occupational exposure to chemicals were used to predict indoor air TME exposure levels in 15 different job tasks. Air monitoring was conducted in order to compare the predicted workplace air concentrations versus the direct measured ones, using both workplace-fixed monitors and personal samplers. And finally, urine samples were collected from 61 workers to assess whether TMEs excretion correlate with job exposure levels. Globally, the predicted air estimates relate well with measured concentrations over the whole set of job tasks. Better predictions were found for certain activities, in particular for steel cutting and welding processes. The values that correspond to the 90th percentile of the exposure distribution were then used in the interaction-based hazard index HIint to assess health risks associated with the mixtures of TMEs. Total cancer risk was also investigated. Results showed high exposures for metals that may elicit respiratory conditions, with a HIint reaching 93.6, the highest levels being for the shielded metal arc welding and metal shearing and slitting tasks. The risk is enhanced by a synergetic effect between Cr, Ni and Cu. High risks of lung and kidney cancers were demonstrated (the predicted life-long total cancer risk for exposed workers is 3.7×10-4). This work shows that mathematical models can be accurate in predicting TME airborne exposure levels for several processes in the metallurgic industry, a result that is of interest to help the different stakeholders to monitor efficiently exposure surveillance and abatement. Progress in industrial hygiene is needed in this industrial sector to reduce the high level of health risks currently experienced by the metalworking workers
Bleeding Takari II (2007) is a large-scale sculptural hanging by El Anatsui held in the collection of the Museum of Modern Art, New York. The artist manages a robust studio practice to construct his works, which are assembled from thousands of aluminum bottle tops recovered from used liquor bottles and connected with copper wire. Bleeding Takari II is predominantly red and silver and can be variably draped with each installation. Existing research on Anatsui’s oeuvre has been largely concerned with installation methods, while long-term preservation and display parameters have not yet been addressed. Industry research and materials analyses were carried out to better understand the object’s composition and to help inform treatment, installation, and preservation recommendations. Infrared (FTIR) and Raman spectroscopy identified various coatings and pigments, x-ray fluorescence (XRF) confirmed the metal as an aluminum alloy, and microfadeometry (MFT) revealed potential light sensitivity of the red bottle tops.
Appearance is a very important property for many different products, therefore it is important to investigate what types of parameters and processing conditions influence their appearance. The proper investigation of this property requires a reliable and repeatable measurement method. Recently, a novel evaluation method has been developed to evaluate the colour inhomogeneity of injection molded specimens. In this study, this novel inhomogeneity evaluation method was used to compare the homogenization properties of different masterbatches. It was shown using this technique that the homogenization properties of different masterbatch recipes can be evaluated and developed. The results of this method were validated by a group of trained technicians and their results were correlated with the inhomogeneity levels derived from the new method.
There is a paucity of information about the occurrence of microplastics (MPs) in edible fish tissues. Here, we investigated the potential presence of MPs in the excised organs (viscera and gills) and eviscerated flesh (whole fish excluding the viscera and gills) of four commonly consumed dried fish species (n = 30 per species). The MP chemical composition was then determined using micro-Raman spectroscopy and elemental analysis with energy-dispersive X-ray spectroscopy (EDX). Out of 61 isolated particles, 59.0% were plastic polymers, 21.3% were pigment particles, 6.55% were non-plastic items (i.e. cellulose or actinolite), while 13.1% remained unidentified. The level of heavy metals on MPs or pigment particles were below the detection limit. Surprisingly, in two species, the eviscerated flesh contained higher MP loads than the excised organs, which highlights that evisceration does not necessarily eliminate the risk of MP intake by consumers. Future studies are encouraged to quantify anthropogenic particle loads in edible fish tissues.
The occurrence of microplastics (MPs) in saltwater bodies is relatively well studied, but nothing is known about their presence in most of the commercial salts that are widely consumed by humans across the globe. Here, we extracted MP-like particles larger than 149 μm from 17 salt brands originating from 8 different countries followed by the identification of their polymer composition using micro-Raman spectroscopy. Microplastics were absent in one brand while others contained between 1 to 10 MPs/Kg of salt. Out of the 72 extracted particles, 41.6% were plastic polymers, 23.6% were pigments, 5.50% were amorphous carbon, and 29.1% remained unidentified. The particle size (mean ± SD) was 515 ± 171 μm. The most common plastic polymers were polypropylene (40.0%) and polyethylene (33.3%). Fragments were the primary form of MPs (63.8%) followed by filaments (25.6%) and films (10.6%). According to our results, the low level of anthropogenic particles intake from the salts (maximum 37 particles per individual per annum) warrants negligible health impacts. However, to better understand the health risks associated with salt consumption, further development in extraction protocols are needed to isolate anthropogenic particles smaller than 149 μm.
The major challenge in organic electronics concerns the stability of organic semiconductor materials which affects the operational lifetime of devices. Recent reports have shown that hydrogen-bonded pigments of the indigoid family are air- and moisture resistant. The magenta pigment quinacridone, a hydrogen-bonded molecule in the solid state with a pentacene like frame, is a perfect example for extraordinary chemical stability. Here, studies using in situ spectroscopic methods comparing quinacridone and pentacene are presented. A different spectral response of their radical cations is observed upon chemical doping. While in pentacene the barrier between doping and irreversible overoxidation is small, this stability toward overoxidation is increased by the heteroatomic structure, leading to hydrogen-bonded quinacridone. This work provides insight into molecular design principles that may lead to next-generation organic semiconductors with enhanced stability and performance.
"Plastics Additives and Testing" is a practical book for engineers and operators and discusses both inorganic and organic chemicals that are widely used as additives in plastics processing operations. It is common practice today to use analytical techniques to improve plastics processing. Because it is critically important to manufacture quality products, a reasonable balance must be drawn between control requirements and parameters for improved processing method with respect to plastics additives. This book serves to implement this balance in the manufacturing line. Written by a successful, international consultant with an excellent publishing track record, it combines plastics additives, testing and quality control and is a valuable and critical book for engineers and operators to have when performing their tasks.
Mainly leather is dyed using anionic dyestuffs such as acid, direct and metal complex dyes, but the use of pigments is not common for leather dyeing. Dye penetration into the inner layers of the leather is a difficult task due to 3D infrastructure of leather. In the present study, an attempt has been made to improve the exhaustion of nano-pigment in dyeing leather by using ultrasound. Optimum dyeing conditions including reduced dyeing time is aimed. Taguchi method was employed for the design of experiments. CIELAB color coordinates reflectance values of dyed leathers were evaluated using a reflectance spectrophotometer. The K/S values of the samples were considered to be proportional to the absorption of nano-pigment into the leather. The optimum level of the effective parameters namely as: wetting time, type of swelling agent, ultrasonic bath time, and amount of pigment were evaluated and confirmed by complementary experiments. J. Color Sci. Tech. 3(2009), 43-51.© Institute for Color Science and Technology.
The prediction and optimization of polymer color properties is a complex problem with no easy method to predict color properties directly and accurately. The problem is especially complicated with the formulation of polymers to achieve the physical properties. By considering the formulation, the neural network has been implemented for prediction of color properties consisting of sigmoid hidden units and a linear output unit arranged in a feed forward back propagation architecture. An optimal design is accomplished for 15, 16, 17, 18, 19, and 20 hidden neurons with four different algorithms including gradient descent with momentum (GDM), resilient backpropagation (resilient backpropagation), scaled conjugate gradient (SCG), and Levenberg–Marquardt (LM) algorithm. The best result in terms of statistics is presented by the LM algorithm with 16 neurons in the designed artificial neural network (ANN) model. The degree of accuracy of the ANN model is proven acceptable in all statistical analysis and shown in results. However, it was concluded that ANN provides a possible method for the prediction of specific color tristimulus values.
ABSTRACT: In current exploration, the artificial neural network (ANN) is executed to reduce the errors in color values of polycarbonate. The network consists of sigmoid hidden units and a linear output unit arranged in a feed forward backpropagation architecture. An optimal design is accomplished for 10, 12, 14, 16, 18, and 20 hidden neurons on a hidden layer with five different algorithms involving batch gradient descent, batch variable learning rate, resilient back propagation, scaled conjugate gradient, and
Levenberg–Marquardt. The training data for ANN are obtained from experimental measurements. There were 22 inputs and three
tristimulus color values L*, a*, and b* were used as an output layer. Statistical analysis in terms of root-mean-squared, an absolute
fraction of variance (R2), as well as a mean square error is used to investigate the performance of ANN. The best result in terms of
statistics is presented by the LM algorithm with 14 neurons in the designed ANN model. The degree of accuracy of the ANN model
in reduction of errors is proven acceptable in all statistical analysis and shown in results. However, it was concluded that ANN
provides a possible method in error reduction in specific color tristimulus values. C � 2013Wiley Periodicals, Inc. Adv Polym Technol
2013, 00, 21402; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21402
KEY WORDS: Additives, Artificial neural network, Color tristimulus values (L*, a*, and b*), Pigments, Plastics, Processing parameters
To provide a novel pathway to improve fastness and levelling properties of acrylic, cationic ultra-fine pigment was prepared by grinding pigment with cationic dispersant agent Tetradecyl dimethyl benzyl ammonium chlorine (TDBAC). Effects of pH, pigment dosage and dyeing temperature were investigated, and dyeing properties of cationic ultra-fine pigment and cationic dye were compared. At pH 8.6 the ultra-fine pigment got the largest pigment adsorption of 99.54% and K/S value of 5.41. The increase of pigment dosage resulted in low adsorption and brilliant colours, and the dyed acrylic yarns presented a maximum K/S value when pigment dosage was 2% (o.w.f). Dyeing rate increased along with temperature, and dyeing balance could be achieved in 15 min at the temperature of 95 °C. Compared with yarns dyed by cationic dye, the acrylic yarns dyed with ultra-fine pigment showed an improvement about 34% in levelling property, and the light fastness was improved from 4 to 6.
In the present investigation, attempts were made to color match mass colored polypropylene by the use of several colorimetric color matching procedures. A color matching procedure consisting of a rough match as a starting point and an iterative algorithm to achieve the exact match to any degree of accuracy was carried out. The rough match was calculated based on the Kubelka-Munk's one and two constant theories. Six different iteration procedures were utilized to achieve the exact match having ΔE2000
Acrylonitryl-butadiene-styrene (ABS) is an engineering polymer with intrinsic yellowness and translucency due to blue wavelength absorption and partial light transmission, respectively. Generally, using titanium dioxide pigment helps to whiten ABS polymer and reduce its intrinsic yellowness. Also, it can impart opacity to polymeric parts. However, it must be considered that this pigment may cause some unfavorable effects in ABS parts. In this article, effects of surface treatment type and content of TiO2 pigment on optical aspects of a general purpose ABS have been investigated. In addition, physical and mechanical characteristics including tensile strength, izod impact strength and Rockwell hardness of the polymer have been studied. By adding titanium dioxide pigment opacity and whitening index increased and yellowness index decreased. It is important to note that surface treatment type of titanium dioxide pigment had no considerable effect on optical properties of titanium dioxide pigmented ABS polymer. The results showed that arising content of organic and inorganic surface treated TiO2 pigments up to 0.5% and 1.5%, respectively, causes to increase impact strength and decrease yield stress and maximum strain of pigmented ABS samples. Above these percentages, impact strength decreased due to agglomeration and decreasing inter-particle spacing. Also hardness of all the ABS samples reduced in the presence of inorganic and organic treated titanium dioxide pigments.
Polymers, and even more so polymer blends, are selected for their particular properties and processing characteristics. It is often necessary to include additives in the polymer formulations, either to facilitate processing, or to extend the life of the polymeric product that is created. Colourants are additives that are principally used for aesthetic purposes. However, the addition of a colourant to a thermoplastic system can lead to unexpected and sometimes detrimental changes in the material properties of that system.
In this review, the general characteristics of polymer blends and the processes involved in manufacturing them are discussed. Additives that may be included in the formulation and the interactions that can arise among the blend components are also described. The relevance of these components and processes are then discussed in regard to blends of polycarbonate and poly(butylene-terephthalate).
ResearchGate has not been able to resolve any references for this publication.