Prediction of spectral reflectance factor distribution of color‐shift paint finishes

As the exterior paint colors of automobiles change the shade of color and brightness according to viewing angle, the appearance of a paint finish is expressed numerically by the reflection characteristic (i.e. reflectance) of paint surface. We figure out that the reflectance of most automotive paint finishes is best measured at the incident angle of 60° and the five aspecular angles of 10°, 18°, 28°, 40°, and 90° on the incident plane (Color Res Appl 2005;30:275–282). However, in the case of the so‐called color shift paint, which changes its paint finish appearance as a jewel beetle, depending on the light source location, the reflection characteristic can not be expressed accurately by conventional measuring methods. As the directions not included in the incident plane need to be taken into account, we have to measure at 48,139 points, changing all the incident angles and reflected angles. (It would take about 16 days.) We, therefore, tried to reduce the number of combinations of incident and reflected angles by analyzing the experimental data. Consequently, we reduced it to 1485 points (about 4 h). When we numerically compared our result to the result of all measuring points, we found that the color difference is 2.76 and therefore our method is practically usable. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 378–387, 2007     

Nondestructive analysis of uneven paint coatings by dynamic heat conduction following flash heating

A method of assessing uneven paint coatings is described, wherein a painted surface is rapidly heated by a light flash and the subsequent surface temperature changes are monitored using thermography. This method exploits the differences in dynamic heat transport caused by variations in paint thickness, using thermographic observation to track differences in temperature related to thickness. During trials with intentionally uneven test specimens spray coated with blackbody paint or red, blue, and green acrylic lacquers, we determined that surfaces with thinner paint coatings exhibited lower temperatures. Based on our findings, this article also discusses the theoretical basis of the detection method. While this technique can detect uneven painting, it is difficult to determine a quantitative relationship between temperature variations in the coated surfaces and paint thickness, since the relationship is dependent not only on the particular substrate and paint, but also on the optical reflectance of the paint. We consider that the proposed method is currently capable of detecting uneven paint coatings with variations in thickness of approximately 20 μm, although improvements in detection resolution are possible. Although detection sensitivity is somewhat low, this technique allows rapid analysis of coatings to assess evenness through visual examination.     

Synthesis and properties of polydimethylsiloxane/graphene oxide modified,water-based polyurethane/polyacrylate

In this study, we prepared polydimethylsiloxane–graphene oxide (PG) modified waterborne polyurethane acrylate (WPUA) films and enhanced their hydrophobicity, thermal stability, and mechanical properties. The prepared films were characterized by Fourier transform infrared and energy spectroscopy analysis; this confirmed the successful incorporation of PG into WPUA. As shown by scanning electron microscopy and atomic force microscopy analysis, the surfaces of the WPUA films were confirmed to have turned smoother and more compact after PG addition. With an optimized amount of PG (0.1%) incorporated into the WPUA film, it exhibited a contact angle improvement of 21.9°, an enhanced decomposition temperature at 5% weight losses of 25 °C, and an elongation at break improvement of 482.92% over those of pure WPUA. The newly synthesized PG–WPUA showed considerable enhancements in its hydrophobicity and thermal and mechanical properties and could be deemed to have potential value as an alternative contender for practical applications in coatings painted on tunnels and highways. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47926.     

Determination of gelation temperature of poly(vinyl chloride) by thermomechanical and thermogravimetric parameters

Preheating between the temperatures of 200 and 280°C is done to a film‐structured poly(vinyl chloride) (PVC) sample, which has a gelation temperature ∼ 250°C. After this preheat, the PVC's thermomechanical and thermal differences, at temperatures before and after thermal gelation, are observed. Consequently, when some thermomechanical and thermal parameters, obtained at temperatures before and after gelation, are compared, it can be said that this is an easier method to determine the gelation temperature of a polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1635–1640, 2005     

Artificial aging and deterioration of oil‐painted Fabriano paper and cardboard paper supports

Fabriano paper and cardboard are commonly used for oil paintings as paper supports. There are different practices for oil painting. Sometimes, painters paint directly on paper supports. They may also impregnate paper supports with linseed oil before painting to prevent the absorption of the binder from the oil‐based paint by the paper, or they may apply a background (e.g., animal glue and calcium carbonate) on the paper supports and then paint their drawings. The effects of aging by heat or ultraviolet light on the mechanical properties (tensile strength, tensile elongation, and tearing resistance), optical properties (changes in color indices), and pH of Fabriano paper and cardboard painted with the aforementioned practices were studied. In addition, the thermal stability of paper painted with these practices was studied with thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Surface reflectance modeling of real objects with interreflections for augmented virtuality

In mixed reality, especially in augmented virtuality, in which real objects are virtualized, it is important to estimate object surface reflectance properties in order to render the objects under arbitrary illumination conditions. Although several methods have been explored, faithfully estimating surface reflectance parameters for complex objects having nonuniform surface reflectance properties or interreflections remains difficult. This article describes a new method for densely estimating the nonuniform surface reflectance properties of real objects constructed of convex and concave surfaces with interreflections. Registered range and surface color texture images are obtained using a laser rangefinder. In the proposed method, light source positions are first determined in order to obtain color images for discriminating diffuse and specular reflection components considering the object geometry. Surface reflectance parameters are then estimated based on radiosity and the Torrance–Sparrow model. The usefulness of the proposed method is shown experimentally. © 2005 Wiley Periodicals, Inc. Col Res Appl, 31, 38–47, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20184     

Application of multi‐flux theory based on Mie scattering to the problem of modeling the optical characteristics of colored pigmented paint films

Multi‐flux theory for multiple scattering calculations in pigmented/protective coating is described. Performance evaluation of the theory is made by comparing theoretically computed reflectance with experimentally measured ones for selected wavelengths for three different paint samples. Diffuse reflectance spectra for hypothetical particulate systems in visible spectral range are generated through computer calculations. Effect of variation in average pigment size and pigment size distribution on reflectance spectra is studied. Overall thrust of morphological characteristics of pigments on the color exhibited by paint dispersion is studied by calculating CIE color and color‐difference parameters of particulate systems. Results show that a very complex relationship exists between the morphological characteristics of pigments and color exhibited by the system. The outcome of the study is important for applications in paint, coating, and plastic industries. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 234–245, 2001     

The surface modification of polyethylene by solution-phase photochemical grafting using short irradiation times

The surface modification of low-density polyethylene by solution-phase photochemical grafting with acrylic acid and acrylamide is described. After irradiation for 3 min, the contact angles of the modified surfaces with water were ca. 20, 30, and 40°C and ca. 40, 40, and 80°C for grafting solutions containing 2M, 1M, and 0.1M of acrylamide and acrylic acid respectively. X-Ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared spectroscopy (ATRIR) of the modified polyethylene surfaces were consistent with the presence of grafts of polyacrylamide or poly(acrylic acid). Grafting using low concentrations of monomers, that is, 0.1M, resulted in a small, 20° decrease in contact angle for grafting with acrylic acid but a larger, 60°C decrease for acrylamide. © 1994 John Wiley & Sons, Inc.     

Atmospheric Plasma Surface Activation of Poly(Ethylene Terephthalate) Film for Roll-To-Roll Application of Transparent Conductive Coating

An effective surface activation is crucial for high-speed roll-to-roll coating of functional films for printed electronics applications. In this article, we report a study of surface treatment of three types of poly(ethylene terephthalate) (PET) films by an argon/oxygen atmospheric pressure plasma and an ambient air atmospheric pressure plasma to obtain the required wettability for subsequent slot die coating of transparent conductive polymer layer using a poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) ink. Prior to plasma treatment, the PET surfaces, which differ in manufacturing process of their preparation, were characterized by X-ray photoelectron spectroscopy. The surface changes after the plasma treatments were characterized by water contact angle measurement and atomic force microscopy. We found that the water contact angles of the three types of untreated PET surfaces were 80.9°, 75.9°, and 66.3°, respectively, and the water contact angles after argon/oxygen plasma treatment at treatment speed of 1 m · min^?1 decreased to 36.2°, 31.9°, and 40.9°, respectively. These conditions were stable from 1 up to 4 days, which are longer than reported values of 15–60 min and sufficient for roll-to-roll coating processes.     

Improving the Hawkyard method for generating reflectance functions

An iterative method was developed by Hawkyard in 1993 for generating reflectance functions, based on a given set of tristimulus values. In a recent article by Dupont (Col Res Appl 2002;27:88–99), many methods for generating reflectance functions were compared, and it was shown that the Hawkyard method is one of the best methods. However, one of the weak points of the Hawkyard method is its iterative nature. In addition, one important issue for the Hawkyard method is its convergence, which has not been addressed. In this article, this issue is examined. The necessary and sufficient condition to achieve convergence, using the Hawkyard method, is given. The method is then modified to make it an analytical method. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 283–287, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20126     

Influence of surface roughness on the diffuse to near‐normal viewing reflectance factor of coatings and its consequences on color measurements

In this work, we discuss the effect of surface roughness on the measurement of the diffuse to near‐normal viewing reflectance factor of coatings and evaluate its impact on the corresponding color coordinates. We compare specular component included (SCI) and excluded measurements. We introduce a gloss‐factor to account for surface roughness in specular component excluded measurements. We present experimental results on samples with different degrees of surface roughness. Samples in this study were chosen to expose the contribution of the surface in the reflectance factor. For slightly rough surfaces, the influence on the measured reflectance factor depends on whether the specular‐component is included or excluded. As the surface roughness increases, the specular‐excluded reflectance factor increases approaching its value with the SCI further roughness lead to similar measurement results in both configurations. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 177–187, 2013.     

The effect of heat sealing temperature on the properties of OPP/CPP heat seal. I. Mechanical properties

The effect of heat sealing temperature on the mechanical properties and morphology of OPP/CPP laminate films was investigated. The laminated films were placed in an impulse type heat sealing machine with both CPP sides facing each other. The temperatures investigated ranged from 100 to 250°C. T‐peel and tensile tests in combination with SEM were used to characterize the heat seals. A minimum seal initiation temperature of 120°C was identified for OPP/CPP laminate heat sealing. Peel strength increased sharply from zero at 110°C to maximum at 120°C, after which a gradual decrease was observed. Tensile strength initially increased until 120°C, after which it gradually decreased until 170°C and assumed a constant value beyond that. The initial rise has been associated to cold crystallization, while the reduction between 120°C and 170°C was due to relaxation in molecular orientation. Beyond 170°C, all the orientation in the laminate has been lost so orientation effects are nullified. Morphological studies with SEM revealed that seals were partially formed at lower temperatures, while the laminates were totally fused together at high temperatures, with intermediate temperatures showing properties that lie in between. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 753–760, 2005     

Effect of moisture‐ingress on adhesion energy in a metal oxide‐polymer system

This work quantifies the damage caused by moisture in a metal coating system under extreme weathering conditions, using Variable Radius Roll Adhesion Test (VaRRAT). Interfacial toughness (adhesion energy) between the metal oxide and the polymer in painted steel panels, studied by using VaRRAT, is observed to fall with increasing temperature and time of exposure to moisture. Possible cause for irreversible loss in adhesion energy in the paint system is attributed to the sorption of free water at the metal oxide–polymer interface. Different failure responses were observed in two different paint–metal systems. Adsorption or diffusion in the Henry's mode is rate controlling in green paints as indicated by the low activation energy of 12 kJ mol^?1. The white samples showed a high activation energy of 30 kJ mol^?1, indicating a mixed process of diffusion as well as chemical to be rate determining. Different paint/binder ratios are responsible for the different responses of these samples. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Generation of antifouling layers on stainless steel surfaces by plasma‐enhanced crosslinking of polyethylene glycol

Polyethylene glycol (PEG) structures were deposited onto stainless steel (SS) surfaces by spin coating and argon radio frequency (RF)‐plasma mediated crosslinking. Electron spectroscopy for chemical analysis (ESCA) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) indicated the presence of  CH₂ CH₂ O structure and C C C linkage, as a result of the plasma crosslinking, on PEG‐modified SS surfaces. Scanning electron microscopy (SEM) indicated complete deposition, and water contact angle analysis revealed higher hydrophilicity on PEG‐modified surfaces compared to unmodified SS surfaces. Surface morphology and roughness analysis by atomic force microscopy (AFM) revealed smoother SS surfaces after PEG modification. The evaluation of antifouling ability of the PEG‐modified SS surfaces was carried out. Compared to the unmodified SS, PEG‐modified surfaces showed about 81–96% decrease in Listeria monocytogenes attachment and biofilm formation (p < 0.05). This cold plasma mediated PEG crosslinking provided a promising technique to reduce bacterial contamination on surfaces encountered in food‐processing environments. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 485–497, 2005     

Investigation of the formation of physical damage on automotive finishes due to acidic reagent exposure

Automotive paints with clear-coat surfaces can be physically damaged by exposure to acidic reagents produced in a smog chamber designed to reproduce real environmental conditions. Visual and reflectance microscopy observations show that deposition of material formed from the reaction of the clear coat and the reagent drop occurs on the paint surface after the drop evaporates to a critical size, with the greatest deposition occurring at the edge of the drop. This type of deposition suggests a free-energy minimization process favoring the formation of stable nuclei at the reagent drop edge. With heating after the drop evaporation to simulate exposure to the sun, a damaged area containing sulfur that is in the shape of a circular ring is observed at the location of the deposits. The majority of the visual damage appears to result from an interaction between the deposit and the paint at elevated temperatures. Results from profilometry, scanning electron microscopy, and reflectance microscopy show that the damaged areas are ring-shaped cracked blisters on the surface resulting from the clear coat separating into layers. © 1993 John Wiley & Sons, Inc.     

Thermal switching of the actuation ability of an electroactive polymer actuator

Electroactive polymer actuators have the simple ability to be actuated by a voltage. In this study, we added a new function: the ability to be actuated by temperature. We used a bending‐electrostrictive actuator made of a polyurethane film. The polyurethane was designed to be rigid at room temperature but to be flexible at temperatures greater than 40°C because of the melting of the soft segment in the polyurethane. Therefore, the actuator showed slight bending in response to a voltage at room temperature. However, it showed significant bending at 61°C. The degree of bending at 61°C was 29 times greater than that at 13°C. Thus, the actuation ability was switched on at 61°C but switched off at 13°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1566–1570, 2005     

Application of the second derivative of the Kubelka–Munk function to the semiquantitative analysis of Roman paintings

In the present survey, we have analyzed Roman paintings in two rooms in a villa at El Ruedo (Almedinilla, Córdoba, Spain). We used different techniques and procedures, such as X‐ray diffraction and diffuse reflectance. We established parameters that define colours in every international system. The diffuse reflectance techniques allowed us to identify the pigments, emphasizing that their mixtures are usually based upon a single chromatic pigment. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 448–456, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.     

The measurement of the moisture transport properties of painted wood — Part I

Conclusions  With the method presented reliable and more informative results can be obtained because no integration or derivation is necessary. The moisture gradient through the painted wood substrate provides material data for both the paint and the wood. The test is easy to carry out and the only not common equipment required is as follows: a room with a constant temperature, an oven of 105°C and some kind of planing cutter. The practical value of the method is that it is a means of determining the paint film diffusivity in a safe and realistic way. The material data can for example be used in computer calculations. A comparison between the results obtained and the results from another study shows good agreement. It is important when designing cup experiments that the whole range of interesting values of moisture content is covered. In this study the cup measurements were carried out in two different areas of moisture. Unfortunately there was a lack of values of moisture content between the two ranges where it would have been desirable to have over-lapping results. The work reported in this paper forms part of a postgraduate thesis     

Synthesis and characterization of quaternary ammonium ionomers

The cationic monomers, MPDMAC₁₆ and MPDMAC₁₈, were obtained by quaternization of methacrylamidopropyl–N,N′‐dimethylamine with n‐alkyl iodides (1‐iodohexadecane and 1‐iodooctadecane) in ethyl acetate. Hydrophobic ionomers of MPDMAC₁₆ and MPDMAC₁₈ with N‐substituted acrylamides were prepared at 60 ± 0.1°C in DMF using AIBN initiator. The cationic monomers and ionomers were characterized by ¹H‐ and ¹³C‐NMR spectroscopy. The copolymer composition was evaluated from elemental analysis data using carbon/nitrogen (C/N) ratio. The molecular weight distributions of ionomers were obtained from GPC analysis. Both the dilute solution and concentrated solution properties of ionomers were studied by viscometry at 30°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1100–1105, 2005     

Color measurements for pearlescent coatings

This article describes recent developments at the National Institution of Standards and Technology in the colorimetric characterization of pearlescent coatings. The goal of this research is to develop a measurement protocol for the accurate color characterization of these coatings using an understanding of their scattering mechanism as a guide. A large ensemble of bi‐directional reflectance measurements on a series of pearl interference pigmented coatings show general trends in the color variations with illumination and viewing angles. These measurements were used to define a set of geometries (illumination angles of 15°, 45°, and 65° and aspecular angles of 15°, 35°, 45°, 70°, and 85°) to characterize the angle dependent color travel observed in these coatings. © 2003 Wiley Periodicals, Inc. Col Res Appl, 29, 38–42, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10210