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Automobile paint chips are a crucial piece of trace evidence for forensic investigators. This is because automotive paints are composed of multiple layers, including the primer, basecoat, and clearcoat, each of which has its own chemical composition that can vary by vehicle make, model, year, and manufacturing plant. Thus, Fourier‐transform infrared (FTIR) spectral databases for automobile paint systems have been established to aid law enforcement in, for example, narrowing search parameters for a suspect's vehicle. Recently, car manufacturers have implemented primers on plastic substrates that are much thinner (~5 μm) than those on metal substrates, making it more difficult to manually separate for analyses. Here, we evaluated FTIR microspectroscopy (μ‐FTIR) and optical photothermal infrared spectroscopy (O‐PTIR) to chemically image cross sections of paint chips without manually separating the layers. For μ‐FTIR, transmission and transflection modes provided the highest quality spectra compared to reflection and μ‐ATR analyses. Point analysis was preferable to chemical imaging, as peaks were identified in the point (MCT) detector's lower spectral range that was below the imaging (FPA) detector's cutoff, such as those associated with titanium dioxide. Reduced spectral range can lead to a similar issue in O‐PTIR analyses depending on instrument configuration. However, its complementary Raman spectra showed strong titanium dioxide peaks, providing an alternate means of identification. Both techniques are likely to become more relevant as they are non‐destructive and avoid manual separation of the layers. O‐PTIR is particularly well‐suited for analysis of the thin primer layer due to its superior spatial resolution. [ABSTRACT FROM AUTHOR]

Discriminating paints of the same color has always been a challenge in automotive paint examination. The process is even more difficult when these paints originate from the same manufacturer and color. Raman spectroscopy is an effective and non‐destructive method that is commonly used to differentiate automotive paint. This method is often used to provide a reliable information about pigments and extenders contained in topcoats and is barely used to examine other layers of paints. In this study, A total of 54 white automotive paints from one single manufacturer (Volkswagen) were prepared and analyzed by Raman Spectroscopy. Each layer of the samples was measured in order to evaluate if Raman spectroscopy can provide good discrimination power. Statistical methods were used to characterize and classify these samples. Correlations between paint characteristics and discriminating factors (such as model, topcoat color code, production year, and assembly plant) were also investigated to get a deeper understanding of automotive paints. [ABSTRACT FROM AUTHOR]

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Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The main objective of this study is a review on the properties and components of base coat in automotive paint industry and its scratch and abrasion resistance improvement by reinforcing nanoparticles as additives. The need of this study is to know different properties of base coat, effect of environment on the base coat and different components of paint. Apart from knowing the paint properties this study makes a glance on paint characteristics. It also describes about the chemical bond formation and changes in chemical structure during the processing of an automotive paint. Evaluation of nanoscale performance on the characteristics of the paint is described in this study. The nanoreinforcements used in property enhancement are nanosilica, nanoalumina, zirconia nanoparticles, nanotitanium dioxide, etc. This study reveals an idea about the type of automotive paint we can use based on their resins, or dispersion medium, i.e., water based or solvent based. In addition, it provides the method to improve the scratch and abrasion resistance of paint. It also gives an idea to overcome the color difference of different substrates in an automobile body. This current study is about the development of vegetable oil-based polymer to synthesize base coat of automobile paint which can be used to reduce the surge of petro-based feed stock in paint industry while moving to the alternative renewable source. [ABSTRACT FROM AUTHOR]

This article analyzes a published formulation of the Navier–Stokes equations cast into surface-following coordinates and provides some additional mathematical background to follow the article. Ubiquitous in the paint shops of automotive plants around the world, a high-speed rotary bell is succinctly described as a rapidly spinning concave axisymmetric surface with liquid paint supplied from a port coinciding with the center of rotation. The spinning surface transfers momentum to the paint film causing it to flow outward. Upon reaching the bell periphery, it is flung off, subsequently forming an atomized spray transferred to an automotive body through advection and electrostatics. Common analytical frameworks of rotating films were spherical or cylindrical coordinate systems where the wetted surface profile of the bell was constrained to follow a coordinate axis. This led to solutions for films modeled with conical, disk-like, or partial hemispherical profiles. An alternative was a more general case using a surface-following orthogonal curvilinear coordinate system along with its derived vector operators. In the unique case of a thin film, these results validated a simpler pattern found in common coordinate systems. [ABSTRACT FROM AUTHOR]

Many innovations arose from the continual and thorough monitoring of overlooked characteristics of materials found in the environment. Automotive paints are always constantly exposed to a broad range of ambient temperature conditions, which reduces their longevity and encourages algae development. Through the effective incorporation of nanotechnology with this lotus effect, it has become possible to provide self-cleaning ability along with air purification and antibacterial performance to automotive surfaces like paint and coating. The addition of nanoparticles such as Titanium dioxide (TiO2) and Silicon dioxide (SiO2) helps to improve functionalities like water or stain resistance, ultra-violet protection, and scratch resistance. When the nanoparticles were added into paint, they degraded the polluting compounds on the material's surface by photo catalysis. Multiple photocatalytic functions and self-cleaning properties were observed in nanoparticles added to polyester acrylic paint. Therefore, this paper discussed the history of automotive painting, nanopaint technology, previous research on the method preparation, development, and current progress, the environmental health aspects of nanotechnology, as well as the performance in terms of automotive surfaces. The study discovered the requirements for nanoparticle dispersion and coating uniformity and appearance on automotive surfaces, which will serve as a benchmark for dispersion and coating methods for automotive surfaces.

Forensic paint comparisons are generally conducted on samples which, while small relative to their source, are still visible to the unaided eye and are thus located and analyzed without great difficulty. Here we demonstrate that a more detailed examination of candidate transfer surfaces can capture materials (questioned samples), even when such traces are invisible to the unaided eye. While certain analytical details (such as layer sequence or a pure FTIR spectrum) may not be obtainable from such traces due to their size and condition, a detailed analysis of the sample characteristics that are analytically accessible may still provide sufficient analytical data to arrive at a probative result. Here we present the application of this approach to a suspected paint transfer case, involving particles of paint as small as 40 μm in size. Using a combination of stereomicroscopy, polarized light microscopy, infrared microspectroscopy, Raman microspectroscopy, and SEM/EDS, all performed on a single, subsample of the original minute particle, it was possible to demonstrate evidence of a two‐way transfer between the suspected sources. Furthermore, the transferred paint particle in one direction could be classified as automotive in nature based on a combination of polymer composition, microscopic texture, and pigment package (which included three specifically identified pigments). This work demonstrates (i) the potential for improving detection limits when searching for a questioned sample, (ii) the potential benefits of higher resolution analyses on samples that would be traditionally labeled as "sample‐size limited," and (iii) the value of case‐specific interpretation over standardized, one‐size fits all report templates. [ABSTRACT FROM AUTHOR]

This study monitors the influence of basic automotive paints on plankton and biofilms of selected microorganisms isolated from the wastewater of an automotive factory. Minimum Biofilm Eradication Concentration-High Throughput Plates system was used for the simultaneous tolerance testing. Minimal inhibitory concentration and minimal lethal concentration of the tested substances were determined for both planktonic cells and their biofilms. The resistance level of biofilms was also tested in standard 96 microtiter plates, whereby the results for bacteria and yeasts were confirmed by the fluorescence microscopy. The results were mutually compared for both plankton and biofilms, as well as for plankton and biofilm of the same microorganisms. In no case, the resistance of the planktonic form was higher than the biofilm for the same microorganism. Saccharomyces cerevisiae PMFKG-F7 in the presence of basic color, as well as Rhodotorula mucilaginosa PMFKG-F8 in the presence of the thinner for rinsing paint, shows high sensitivity in planktonic form, whereby the same species are the most resistant in the form of biofilm for the same substances. The highest resistance to all test substances was shown by the biofilm of R. mucilaginosa PMFKG-F8, as well as Candida utilis PMFKG-F9 which was significantly resistant in both tested forms. The obtained results suggest that autochthonous microorganisms that form biofilms can significantly improve the process of removing car paints from the wastewater and being thus new grounds for the development of new biotechnologies. [ABSTRACT FROM AUTHOR]

This population study was conducted to assess the frequency of physical, microscopical, and chemical properties of automotive paint chips. Population studies of trace evidence provide valuable analytical data for criminalists to assess evidentiary significance. Two‐hundred automotive paint chips were collected from auto body shops from the Northeastern United States. All samples were analyzed using stereomicroscopy, brightfield, and polarized light microscopy. Red paints were targeted for further analysis using a sequence of modern instrumental techniques commonly used by forensic paint examiners: Fourier‐transform infrared (FT‐IR), Raman, and ultraviolet–visible (UV–Vis) microspectroscopy. The discrimination potential of each analytical method was evaluated by inter‐comparing the paint samples. Results demonstrated that macroscopic and microscopic properties were able to differentiate 99.995% of the population (one undifferentiated pair out of 19,900). When combined with either FT‐IR or UV–Vis microspectroscopy, all paints were differentiated. The results of this research lead to the conclusion that one would not expect to encounter two indistinguishable paint chips originating from different sources during the investigation of a single event. [ABSTRACT FROM AUTHOR]

Abstract With painting operations as a major origin of environmental concerns in automotive industry, novel and effective technologies are required for treatment of automotive paint wastewater. In this experimental study, a continuous-flow electroflotation reactor with effective volume of 38.4 L and stainless-steel electrodes were designed and implemented for treatment of this industrial wastewater. The system performance, namely the total suspended solids removal, was investigated with operational parameters including the hydraulic retention time, current density and influent total solids concentration. The removal rate ranged between 57 ± 1% and 95 ± 7% under initial total solids concentration 3000 mg/L, current density 50 A/m2, retention time 4 min, and initial total solids concentration 500 mg/L, current density 100 A/m2, retention time 8 min conditions, respectively. It was found that the removal rate decreases with the increase of influent total solids concentration. The results revealed that the suspended solids removal rate is directly related to the applied current density and hydraulic retention time. The electroflotation system showed to be energy-efficient compared to the commercial systems. Further, an empirical equation for the total suspended solids removal rate was established with the R2 value of 92.74%. The independent variables were the retention time, influent suspended solids concentration and applied current density. Graphical abstract Image 1 Highlights • Electroflotation (EF) is use of electrolysis bubbles to remove suspended particles. • A continuous-flow EF reactor was used for treatment of automotive paint wastewater. • With the maximum TSS removal of 95.0%, the EF was effective and energy-efficient. • Increasing the electrical current and process time improved the system performance. [ABSTRACT FROM AUTHOR]

The quantification of coating adhesion on substrates is an important technology that has recently received much attention in automotive industry because the adhesion characteristics of automotive paints have a great influence on color and appearance of automobiles. Here, we present a robust and precise method for quantifying the coating adhesion of automotive paints on flat substrates using new microgap pull-off test based on the application of a micrometer-thick layer of adhesive to the divided compartments. The influence of water and organic material penetration on the coating adhesion between paint and plastic substrate is investigated in order to quantitatively measure the water resistance and organic compound resistance of automotive paints. When the paint absorbed moisture and organics, they penetrated through the paint surface to interfere with the coating adhesion between the plastic substrate and the paint layer, thereby reducing the initial coating adhesion. In addition, we investigated the effect of chlorinated polyolefin (CPO) content on the coating adhesion between nonpolar plastic substrate and polar paint coating. As the CPO content in polar acrylic paints increased, the coating adhesion of the polar paint to nonpolar plastics was increased due to the compatibilization effect of CPO resin in the coating interface. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Abrasion resistance of polyurethane clearcoats is significantly enhanced by nano-silica additives. • Scratch, abrasion, SEM & TEM results are presented. • The effect of different weight fractions and applied abrasion forces is evaluated. • Abrasion resistance improvement is discussed using wear mechanisms. • Much more economical coatings can be fabricated using precipitated type of nano-silica reinforcement. Abstract Nano-particulate reinforced polymer composites are recently being used in many laboratory and industrial applications such as automotive manufacturing industries. However, still further studies are demanded to enhance tribological and mechanical properties leading to achieve as the best resilience as possible required for severe loading or harsh environmental conditions. The purpose of the current paper is studying the scratch and abrasion resistance of the acrylic-based polyurethane nano-particulate clearcoats reinforced by the two types of fumed and precipitated nano-silica reinforcements. To do this, scanning electron microscope (SEM), transmission electron microscope (TEM), scratch and pin-on-disc abrasion resistance experiments were carried out. It was found that the nano-silica additives considerably enhance tribological and mechanical properties of the examined coatings. It was also found that the precipitated type of nano-silica clearcoat is hard enough, tough, and very resistant against wear and environmental conditions and therefore can be considered instead of the too expensive fumed type of nano-silica. [ABSTRACT FROM AUTHOR]

Resumo Mesmo com a evolução considerável das técnicas de pintura automotiva nas últimas décadas, o para-choque é uma autopeça que ainda tem diversos problemas relacionados ao aspecto da sua superfície pintada. O objetivo deste artigo foi identificar os fatores de aplicação do verniz que interferem na intensidade do aspecto de casca de laranja em superfícies de para-choques pintados e propor uma combinação ótima dos fatores através da metodologia do projeto robusto. Na pesquisa realizada no setor de pintura automatizada de uma empresa de para-choques, o projeto robusto auxiliou na identificação das formas de variabilidade do processo de produção através da aplicação de um experimento e de técnicas estatísticas, de forma ágil e com pouco desperdício de material. O experimento testou várias combinações dos níveis dos fatores de aplicação do verniz (velocidade, vazão, rotação por minuto, alta tensão, ar modelador) em amostras de para-choques. A intensidade da casca de laranja em superfícies pintadas de verniz das amostras foi medida pelo equipamento Wave Scan, o qual fornece a leitura do comprimento de onda em função de duas medidas: Short Wave e Long Wave. Os principais resultados obtidos através da análise da variância da razão sinal ruído revelaram que os fatores que têm efeitos significativos no valor resposta do comprimento de onda Short Wave são: rotação por minuto, alta tensão além das interações vazão*alta tensão e velocidade*alta tensão. Já os fatores que afetaram significativamente o valor resposta do comprimento de onda Long Wave são: vazão, ar modelador, rotação por minuto, alta tensão e a interação velocidade*alta tensão. Como resultado da análise das médias do sinal ruído, foi apresentada neste trabalho a combinação ótima dos fatores: velocidade = 920 m/s; vazão = 160 mililitros/minuto; ar modelador = 180 bar; rotação = 90 rotações/minuto; alta tensão = 180 quilovolts.

A special focus has recently been made on the enhancement of the mechano-tribological properties of the clearcoats commonly used in several industries such as the automotive manufacturing sectors. However, still further investigations are needed for the better understanding of the behavior of such clearcoats in different working conditions. The purpose of the current research was investigating the erosion resistance, adhesive strength, micro-hardness and weathering stability of the acrylic-based polyurethane nano-composites which were reinforced by precipitated and fumed nano-silica particles. To achieve this, Zeta Sizer, scanning electron microscope (SEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR) analyses were used. Furthermore, a series of experimental tests including the adhesive strength, toughness, micro-hardness and erosion resistance were carried out to measure the mechanical response of the fabricated clearcoats. It was concluded that the nano-silica additives significantly improve the adhesive strength, and highly increase the micro-hardness as well as the erosion resistance. It is also found that the precipitated nano-silica is able to create an inexpensive, hard and tough coatings rendering it very durable against wear, weathering conditions, and, thus, can be potentially employed as a reinforcing filler and as a replacement to the fumed clearcoats that are usually much more expensive than the proposed reinforcement. [ABSTRACT FROM AUTHOR]

Automotive paint is common trace evidence that plays a significant role in many vehicle-related criminal cases. However, the conventional methods of obtaining tomographic images tend to damage the samples. Optical coherence tomography (OCT) is a novel method to obtain high-resolution and cross-sectional images of the automotive paints in a non-destructive, and high-speed manner. In this study, OCT was applied to image and analyze the automotive paint, using scanning electron microscope (SEM) as reference. Eight automotive paint samples of different brands were examined. The images of multi-layer structures provided by OCT system with 5μm depth resolution were consistent with those by SEM. To distinguish different paints with similar visual appearance, we extracted internal structural features from the images using peak analysis and optical attenuation fit. Six characterized parameters were found to distinguish the samples including the optical path length (OPL) of base coat, the optical attenuation coefficient (OAC) of base coat, the OPL of clear coat, the back-scattering ratio (BSR) of clear coat and base coat, the OPL of primer surfacer, and the BSR of base coat and primer. Statistical differences were evaluated by an independent t-test with p<0.05. OCT was applied to analyze repainted paint as well. Three-dimensional OCT reconstruction of the paints was also implemented to create en face (transverse section) images for morphology examination and comparison. These results suggest that OCT imaging can provide additional new features for analyzing the automotive paints and thereby may be a promising supplement to traditional methods. Meanwhile, the OCT system is favorable for achieving in-situ and real-time examination at the scene of crime. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the influence of several analytical parameters on the variability of Raman spectra of paint samples. In the present study, microtome thin section and direct (no preparation) analysis are considered as sample preparation. In order to evaluate their influence on the measures, an experimental design such as 'fractional full factorial' with seven factors (including the sampling process) is applied, for a total of 32 experiments representing 160 measures. Once the influence of sample preparation highlighted, a depth profile of a paint sample is carried out by changing the focusing plane in order to measure the colored layer under a clearcoat. This is undertaken in order to avoid sample preparation such a microtome sectioning. Finally, chemometric treatments such as principal component analysis are applied to the resulting spectra. The findings of this study indicate the importance of sample preparation, or more specifically, the surface roughness, on the variability of the measurements on a same sample. Moreover, the depth profile experiment highlights the influence of the refractive index of the upper layer (clearcoat) when measuring through a transparent layer. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] MW2DCOS and PCA were combined for the first time to interpret time serial spectra. [•] Three stages of the curing process of a paint sample were found by MW2DCOS and PCA. [•] Time-resolved spectral changes are shown in AP-MW2D correlation spectra. [•] The time-resolved relationship of spectral peaks is revealed by PP- and PL-MW2DCOS. [ABSTRACT FROM AUTHOR]

Chrome Yellow ( PbCr O4· xPbSO4) was a common pigment in U. S. automobile OEM finishes for more than three decades, but in the early 1990s its use was discontinued. One of its main replacements was Bismuth Vanadate ( Bi VO4· nBi2 Mo O6, n = 0-2), which was commercially introduced in 1985, as this inorganic pigment also produces a very bright hue and has excellent outdoor durability. This paper describes the in situ identification of Bismuth Vanadate in automotive finishes using FT- IR and dispersive Raman spectroscopy and XRF spectrometry. Some differentiation of commercial formulations of this pigment is possible based on far-infrared absorptions, Raman data, and elemental analysis. The spectral differences arise from the presence or absence of molybdenum, the use of two crystal polymorphs of Bi VO4, and differences in pigment stabilizers. Bismuth Vanadate is usually not used alone, and it is typically found with Isoindoline Yellow, hydrous ferric oxide, rutile, Isoindolinone Yellow 3 R, or various combinations of these. [ABSTRACT FROM AUTHOR]

Abstract: Synchrotron FTIR microspectroscopy was used to characterise and assess the chemical diversity of electrocoat primer, primer surfacer and basecoats of automotive paint samples from 75 vehicles representing a range of international car manufacturers. Significant diversity was found in the synchrotron FTIR data from the primer surfacer coats. Classification using principal component analysis revealed 14 discrete groups, which could be associated with the country of manufacture, the specific manufacturer and manufacturing plant, the year of manufacture of the vehicle and in some instances the number of layers in the paint system. The model generated from the primer surfacer was significantly more discriminating than a previous model generated from FTIR analysis of clear coats of the same vehicles. Analysis of the primer surfacer also avoids issues of possible environmental degradation and component migration seen with FTIR analysis of automotive clear coats. Providing such information concerning vehicle origin would aid in the development of investigative leads from the analysis of questioned automotive paint samples located at the scene of a crime or on the body/clothing of a hit and run victim. [Copyright &y& Elsevier]