Gloss Measurements Research Articles

Common Cosmetic Compounds Can Reduce Air Pollution-Induced Oxidative Stress and Pro-Inflammatory Response in the Skin

Introduction: Constantly increasing air pollution (AP) poses a concern affecting not only our health but also our skin. A typical manifestation of the skin damage induced by AP is its premature aging, irritation, skin barrier impairment, pigmentation disorders, and development or exacerbation of various skin diseases. For these reasons, it is crucial to protect the skin from the negative effects of AP. In this study, we evaluated the ability of some compounds commonly used in dermatological or cosmetic preparations with various biological activities to reduce AP-induced skin damage. Methods: We established a new experimental model using porcine skin explants exposed to cigarette smoke (CS) in which we determined the level of reactive oxygen species (ROS) in the stratum corneum, skin barrier lipids peroxidation, and gene expression of the pro-inflammatory cytokine interleukin 6 in the epidermis. Then, we tested several polysaccharides and their derivatives such as sodium hyaluronate (SH) of different molecular weight (MW, 1.6 MDa, 300 kDa, 15 kDa, 5 kDa), yeast glucomannan, schizophyllan, and carboxymethyl β-glucan, then vitamin C derivative sodium ascorbyl phosphate, niacinamide, and D-panthenol for their ability to prevent CS-induced skin damage. For the evaluation and comparison of their mechanism of action, film-forming effect was determined by TEWL and gloss measurements and the antioxidant properties were assessed by DPPH assay. Results: In the skin samples exposed to CS, we observed significant negative changes such as the presence of large amount of ROS in the stratum corneum, high level of skin barrier lipids peroxidation and upregulated IL6 gene expression. Pretreatment of the skin samples with all the tested substances significantly prevented CS-induced skin damage. The most effective were high MW SH probably due to its best film-forming effect and sodium ascorbyl phosphate with the best antioxidant properties. Conclusion: AP leads to a significant skin damage which can be effectively prevented using some conventional cosmetic and dermatological ingredients with various mechanisms of action.

Evaluation of novel cleaning systems on mock-ups of unvarnished oil paint and chalk-glue ground within the Munch Aula Paintings Project

Low-risk removal of embedded surface soiling on delicate heritage objects can require novel alternatives to traditional cleaning systems. Edvard Munch’s monumental Aula paintings (1911–16) have a long history of exposure to atmospheric pollution and cleaning campaigns that have compromised the appearance and the condition of these important artworks. Soiling removal from porous and water-sensitive, unvarnished oil paintings continues to be a major conservation challenge. This paper presents the approach and results of research into the effect and efficiency of three novel systems used for soiling removal: soft particle blasting, CO2-snow blasting, and Nanorestore Gel® Dry and Peggy series hydrogels. Cleaning tests were performed on accelerated-aged and artificially soiled mock-ups consisting of unvarnished oil paint and chalk-glue grounds. Visual and analytical assessment (magnification using a light microscope and scanning electron microscope, as well as colour- and gloss measurement) was carried out before and after mock-up cleaning tests and the results were compared to those obtained using the dry polyurethane sponges employed in the most recent Aula surface cleaning campaign (2009–11). Although the results varied, the Nanorestore Gel® series proved promising with respect to improved soiling removal efficiency, and reduced pigment loss for the water-sensitive surfaces evaluated, compared to dry sponges.

A Study on the Treatment Effect and Wave Efficiency of Heat Perm Added Camellia Oil

This study is for the treatment effect and wave efficiency shown by using camellia oil, a natural material, for hair damaged by heat perm, a chemical treatment. For this, An experimental group containing camellia oil and a control group without it were prepared. and then, hair tensile strength measurement, absorbance measurement, SEM(Scanning Electron Microscope) observation, and hair gloss measurement were tested. First, in the tensile strength measurement, the tensile strength of the heat perm with camellia oil was higher than that of the heat perm without camellia oil. And as a result of absorbance measurement using methylene blue, the average absorbance of hair containing camellia oil was low. Second, in SEM, heat perm containing camellia oil showed less cuticle damage. Also, there was no cuticle damage in the heat perm containing camellia oil compared to the heat perm without camellia oil in the time observation. As a result of the gloss measurement, the degree of damage according to the time of the heat perm increased, but the damage was less in the heat perm including camellia oil. Based on these results, it was found that camellia oil had a high treatment effect of heat perm.

Self-Healing UV-Curable Acrylate Coatings for Wood Finishing System, Part 2: Impact of Monomer Structure and Self-Healing Parameters on Self-Healing Efficiency

Wood is increasingly used in construction for the benefits it brings to occupants and for its ecological aspect. Indoor wood products are frequently subject to mechanical aggressions, their abrasion and scratch resistance thus need to be improved. The coating system ensures the wood surface protection, which is, for wood flooring, a multilayer acrylate UV-curable 100% solid system. To increase the service life of wood flooring, a new property is studied: self-healing. The objective of this study is to observe the impact of monomer structure on self-healing efficiency and the effect of self-healing parameters. A previous formulation was developed using hydrogen bond technology to generate the self-healing property. In this paper, the assessment of the formulation and the self-healing parameters’ impact on self-healing efficiency as well as the physicochemical properties are presented. The composition of the monomer part in the formulations was varied, and the effect on the conversion yield (measured by FT-IR), on the Tg and crosslinking density (measured by DMA) and on mechanical resistance (evaluated via hardness pendulum, indentation, and reverse impact) was analyzed. The self-healing efficiency of the coatings was determined by gloss and scratch depth measurements (under constant and progressive load). It was proven that monomers with three acrylate functions bring too much crosslinking, which inhibits the chain mobility necessary to observe self-healing. The presence of the AHPMA monomer in the formulation permits considerably increasing the crosslinking density (CLD) while keeping good self-healing efficiency. It was also observed that the self-healing behavior of the coatings is different according to the damage caused. Indeed, the self-healing results after abrasion and after scratch (under constant or progressive load) are different. In conclusion, it is possible to increase CLD while keeping self-healing behavior until a certain limit and with a linear monomer structure to avoid steric hindrance. Moreover, the selection of the best coatings (the one with the highest self-healing) depends on the damage.

Effect of Rosin Modification on the Visual Characteristics of Round Bamboo Culm.

Rosin was used to treat round bamboo culm using the impregnation method. The quantitative color and gloss measurements combined with a qualitative eye tracking experiment were used to evaluate the effect of rosin treatment under different temperatures on the visual characteristics of the bamboo surface. Surface morphology analysis was also used to explore the mechanism of modification. The results showed that proper heating of the modified system was conducive to the formation of a continuous rosin film, which increased the gloss value. The maximum gloss value of 19.6 achieved at 50 °C was 122.7% higher than the gloss value of the control group. Heating decreased the brightness of the bamboo culm and changed the color from the green and yellow tones to red and blue. Additionally, at temperatures higher than 60 °C, the bamboo epidermal layer was damaged or shed, and stripes formed on the culm surface. The density of these stripes increased with an increase in treatment temperature. Eye movement experiment and subjective evaluation showed that high gloss would produce dazzling feeling, such as at 50 °C, while low gloss will appear dim, such as at 80 °C, while the gloss at 40 °C and 60 °C were appropriate. Additionally, the solid color surface below 60 °C had a large audience of about 73%, and the striped surface above 60 °C was preferred by 27% of the subjects.

Development of a System to Measure the Optical Properties of Facial Skin using a 3D Camera and Projector

We have developed a system to measure both the optical properties of facial skin and the three-dimensional shape of the face. To measure the three-dimensional facial shape, our system uses a light-field camera to provide a focused image and a depth image simultaneously. The light source uses a projector that produces a high-frequency binary illumination pattern to separate the subsurface scattering and surface reflections from the facial skin. Using a dichromatic reflection model, the surface reflection image of the skin can be separated further into a specular reflection component and a diffuse reflection component. Verification using physically controlled objects showed that the separation of the optical properties by the system correlated with the subsurface scattering, specular reflection, or diffuse reflection characteristics of each object. The method presented here opens new possibilities in cosmetology and skin pharmacology for measurement of the skin's gloss and absorption kinetics and the pharmacodynamics of various external agents.

A Study on the Hair Improvement Effect of Dongbaek Oil on Dye Hair

This study used camellia oil, a natural ingredient, to study whether camellia oil has the effect of improving the hair quality damaged by dyeing. first, In order to find out the change in chromaticity of dyed hair due to the content of camellia oil, L*, a*, and b* value measurement were performed. As a result, Through the L* value of the dyed hair according to the camellia oil content, it was found that the dyed hair containing 2 g of camellia oil had a subtle effect of color clarity and dyeability. There was also less fading. In order to determine the degree of damage to the hair, the absorbance measurement using methylene blue showed a decrease in the average in hairs dyed with 2 g of camellia oil, indicating that there was a hair improvement effect in hairs dyed with camellia oil. As a result of studying whether the hair dye containing camellia oil has the effect of improving hair quality, the absorption strength decreased and the tensile strength increased. In addition, absorbance measurement, gloss measurement, and SEM (Scanning Electron Microscope) experiments were conducted. As a result, It was confirmed that there is an effect of improving hair quality in terms of the constant arrangement of cuticles on the hair surface and increasing the gloss of the hair. It was found that camellia oil, a natural ingredient, has a high effect on improving hair quality of dyed hair in order to minimize damage to dyed hair.

Towards Sustainable Museum Conservation Practices: A Study on the Surface Cleaning of Contemporary Art and Design Objects with the Use of Biodegradable Agents

Green contemporary art conservation cleaning methods are explored as sustainable museum practices, ensuring the conservator’s health and reducing the environmental impact. The performance of selected biodegradable cleaning agents, namely deionised (DI) water, a chelate based on trisodium salt of methylglycinediacetic acid (MGDA), Trilon® M, a non-ionic surfactant based on alkoxylated fatty alcohols (Plurafac® LF900), and two solvents, limonene and ethyl lactate, was evaluated for the surface cleaning of polymethyl methacrylate (PMMA), polylactic acid (PLA), polypropylene (PP), and plasticized polyvinyl chloride (pPVC). Plastic mockups were used untreated or artificially soiled, simulating particulate matter or sebum stains produced by handling. Furthermore, the efficacy of ink removal from the plastic’s surface was evaluated. Surface examination was carried out using optical microscopy (OM), scanning electron microscopy (SEM), and atomic force microscopy (AFM), while μ-Raman and gloss measurements complemented the cleaning assessment methodology. The cleaning agents’ potency depends on the type of plastic, precluding a general cleaning protocol. However, their cleaning efficacy is very promising, enriching the available choices for the cleaning of plastics, using sustainable materials and practices. This study offers valuable information to the conservation field regarding the effects of the selected biodegradable cleaning agents on each type of plastic, their application method, and their cleaning efficacy for the removal of different types of soil and ink.

Haptic and Aesthetic Properties of Heat-Treated Modified Birch Wood

This paper deals with the effect of heat treatment on the selected physical properties of birch wood. Five stages of heat treatment were used, ranging from 160 °C to 200 °C, in 10 °C increments, having a peak treatment duration of 3 h for each level. Primarily, changes in thermal characteristics, namely conductivity, diffusivity, effusivity, volume heat capacity, changes in colour and gloss parameters, mass loss due to modification and different moisture content in wood under given equilibrium climatic conditions, were monitored. The ISOMET 2114 analyser was used to measure the thermal characteristics. The measurement principle of this analyser is based on the analysis of the thermal response of the analysed material to pulses of heat flow. Measurements of colour, gloss, density and moisture content were carried out according to harmonised EN standards. The aim was to experimentally verify the more or less generally known more positive perception of heat-treated wood, both by touch and sight, i.e., the warmer perception of darker brown shades of wood. In terms of thermal characteristics, the most interesting result is that they gradually decrease with increasing treatment temperature. For example, at the highest treatment temperature of 200 °C, there is a decrease in thermal conductivity by 20.2%, a decrease in volume heat capacity by 15.0%, and a decrease in effusivity by 17.7%. The decrease in thermal conductivity is nearly constant at all treatment levels, specifically at this treatment temperature, by 6.0%. The fact mentioned above is positive in terms of the tactile perception of such treated wood, which can have a positive effect, for example, in furniture with surface application of heat-treated veneers, which are perceived positively by the majority of the human population visually or as a cladding material in saunas. In this context, it has been found that the thermal modification at the above-mentioned treatment temperature of 200 °C results in a decrease in brightness by 44.0%, a decrease in total colour difference by 38.4%, and a decrease in gloss (at an angle of 60°) by 18.2%. The decrease in gloss is only one essential negative aspect that can be addressed by subsequent surface treatment. During the heat treatment, there is also a loss of mass in volume, e.g., at a treatment temperature of 200 °C and subsequent conditioning to an equilibrium moisture content in a conditioning chamber with an air temperature of 20 ± 2 °C and relative humidity of 65 % ± 5%, there was a decrease by 7.9%. In conclusion, the experiments clearly confirmed the hypothesis of a positive perception of heat-treated wood in terms of haptics and aesthetics.

Corrosion Resistance Synergistic Appraisal of Titanium-Impregnated Bisphenol A-Type Epoxy Duplex Coating System in Stimulated and Natural Marine Environments of Southeastern Coastal Area of China–Pakistan Economic Corridor

This research endeavor is aimed at developing a protective coating for marine service conditions of the southeastern coastal area of the China–Pakistan Economic Corridor. Bisphenol A-type epoxy-based protective coatings were prepared by impregnating exotic titanium metal microparticles into two different proportions, i.e., 5% and 10% (w/w). Film hardness measurement by pencil test, adhesion measurement by the crosshatch-tape test, chemical and heat resistance test, gloss measurement, natural exposure, and salt spray testing have demonstrated that Ti-enriched coatings have performed better than the virgin epoxy coating. Moreover, scanning electron microscopy has depicted more surface degradation. Fourier transform infrared spectroscopy has indicated higher mass loss and chain scission in the virgin epoxy coating than the Ti-enriched coatings. In addition, these Ti microparticles have filled up the cavities/imperfections, reduced cracking, promoted crosslinking during the curing, and cordoned-off passage of corrodents and moisture, thus improving epoxy resin coating features. These results have widened the scope of Ti-embedded epoxy coatings against atmospheric corrosion for highly corrosive marine sites.

Preparation and characterization of low gloss UV-curable coatings based on silica surface modification using an acrylate monomer

UV-curable coatings are attractive for a wide range of applications due to several advantages, including rapid polymerization rates, increased production rate, and low environmental impact (from limited use of volatile organic compounds). In the present work, UV-curable formulations were prepared from various acrylate oligomers and monomers and modified silica as a matting agent. To improve compatibility between the acrylate-based coating and silica, the surface of the silica particles was modified in two steps. First, to introduce amino-reactive groups to the surface, (3-aminopropyl) triethoxysilane (APTES) was grafted onto the silica. Subsequently, the second step consisted of grafting an acrylate monomer, dipropylene glycol diacrylate (DPGDA), via the aza-Michael reaction. The functionalization with acrylate chains promotes compatibility with the acrylate-based coating formulation and results in a very low gloss surface. The modified silica was characterized through a variety of techniques, including thermogravimetric analysis (TGA), 29Si and 13C NMR and laser diffraction particle size analysis. The matte UV-curable coatings were characterized using viscometry, photo-DSC (kinetic analysis) and real-time FTIR (conversion rate determination), gloss measurements, profilometry (surface roughness analysis), as well as scratch testing (abrasion resistance). This silica modification allows the formation of coatings with low gloss levels at loadings as low as 10% wt modified silica.

Acrylic‐ester‐polyol based novel two‐component polyurethane clear coat: Evaluation of performance characteristics

AbstractIn the current study, a combination of acrylic polyol (AP) and ester polyol (EP) were synthesized and reacted at variable ratios with hexamethylene diisocyanates and isophorone diisocyanates to prepare a transparent two‐component polyurethane (PU) coating formulation. The formations of the polyol system, isocyanate system, and the PU systems were confirmed by 1H nuclear magnetic resonance and Fourier‐transform infrared spectroscopy. Transparency of the coatings was examined using haze, and gloss measurement, which showed acrylic‐ester‐polyurethane (aePU‐5 and aePU‐6) have 91.5% and 91.8% transparency and gloss of 90.3 and 90.7 GU respectively. The thermal properties like Tg and the thermal stability of the coatings were verified using differential scanning calorimetry, and thermogravimetric analysis respectively which was found to increase with increasing EP content and decreasing AP content which may be ascribed to improved compatibility of copolymers, and homogeneity in PU along with enhanced crosslinking density. The degree of adhesion of coating with the substrate was validated from lap‐shear, and cross‐cut tape test which showed improved performance at AP:EP ratio of 60:40. The coatings were found to exhibit resistance toward pencil hardness with aePU‐5 and aePU‐6 having the optimum resistance of 9H. The surface morphology and topography were observed under scanning electron microscopy, and atomic force microscopy, respectively. The outcome confirms the higher smoothness of the surfaces subjected to the increase in EP content. The PU system with 40 wt% AP content and 60 wt% EP designated as aePU‐5 was found to exhibit optimum performance.

BRDF and gloss computation of polyurethane coatings from roughness measurements: Modelling and experimental validation

Polyurethane coatings applied on PVC flooring substrate may influence its optical properties, especially gloss. Basically, rough surfaces look matte while smooth ones look glossy. However, the quantitative link between roughness and gloss remains insufficiently modelled. In this article, a microfacet-based model which predicts the BRDF from the 3D roughness slope distribution function f(dz/dx,dz/dy) is developed. Contrary to the different models existing in the literature, the computations are based directly on measured roughness from which the local slope distribution function is extracted. The model is applied to eight polyurethane coatings with different roughness and gloss. The results of the computations are compared to BRDF and gloss measurements. It is shown that this approach allows a good prediction of optical properties. In particular, the model predicts remarkably well the measured 60° gloss values.

Accelerated weathering resistance of high-density polyethylene composites reinforced with microcrystalline cellulose and fire retardants

In this study, high-density polyethylene (HDPE) composites reinforced with microcrystalline cellulose (MCC) and fire retardants, ammonium zeolite (AZ) and mono ammonium phosphate (MAP) were exposed to ultraviolet (UV) radiation using an accelerated weathering test chamber for total of 672 h. The weathering effects on the surface characterization and morphology of the composites were examined with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), color, gloss and surface roughness measurements. Furthermore, tensile and flexural tests were determined after the weathering exposure. The results showed that the weathering of composites led to changes on the investigated properties. As a result of surface roughness measurement, the highest Rz (mean peak-to-valley height) values were obtained from the composite surfaces of the HDPE/AZ10 (86/10, w/w) and the HDPE/MCC/MAP10 (71/15/10, w/w). The SEM studies confirmed that AZ addition resulted in some protrusion at the composite surfaces while MAP addition caused some coarsening on the composite surfaces. After the weathering, the decrease in mechanical strengths of the samples was found as 32%. The overall mechanical properties were not considerably affected with 672 h of the weathering exposure.

Development of a perceptually uniform physical scale for visual assessment of specular gloss

Measuring gloss, visually or instrumentally, has been a challenge in many manufacturing and service industries. However, there exists no standardized method for visual evaluation of equidistance specular gloss. This study aimed to design and prepare a psychometric visually equispaced specular gloss scale for the visual measurement of gloss or any other geometric appearance attribute. To this end, a series of lithographically printed black papers, with different levels of gloss from low to high, were prepared to constitute a visually uniform specular gloss scale. Fourteen observers visually quantified the scale in a unidirectional illumination at three different geometries. Analyzing the results shows that the 60° geometry can quantify the equivalent specular gloss efficiently. A uniform specular gloss scale was prepared by assessing the prepared scale visually under the unidirectional illumination at the 60° geometry. Such a visually uniform specular gloss scale could be employed to develop a standard visual evaluation method of specular gloss in all related industries.

Nano- and Micro- Carnauba Wax Emulsions versus Shellac Protective Coatings on Postharvest Citrus Quality

Coatings are generally applied to fruit as microemulsions, but nanoemulsions are still experimental. ‘Nova’ mandarins (Citrus reticulata) were coated with shellac or carnauba (Copernica cerifera) microemulsions or an experimental carnauba nanoemulsion; these were compared with an uncoated control during storage for 7 days at 20 °C. Coatings were also tested on ‘Unique’ tangors (C. reticulata × C. sinensis) stored for 14 days at 10 °C followed by a simulated marketing period of 7 days at 20 °C. Fruit quality evaluations included weight loss, gloss, soluble solids (SS), titratable acidity (TA), pH, SS/TA ratio, internal CO2, O2, fruit juice ethanol, and other aroma volatile content. Sensory visual shine and tangerine (C. reticulata) flavor rank tests after storage were conducted, followed by an off-flavor rating. The carnauba waxes resulted in less weight loss compared with the uncoated control and shellac coating during both experiments. There were no differences in gloss measurements of ‘Nova’ mandarins; however, shellac-coated fruit ranked highest for shine in a sensory test. For ‘Unique’ tangors, initially, shellac showed the highest gloss (shine) measurement; however, at the end of storage, the nanoemulsion exhibited the highest gloss, although it was not different from that of the microemulsion. Similarly, after storage, the nanoemulsion ranked highest for visual shine, although it was not different from that of the microemulsion. There were only minor differences in SS, TA, pH, and SS/TA among treatments. The internal CO2 gas concentration and juice ethanol content generally increased and internal O2 decreased during storage. The highest levels of CO2 and ethanol were found for the shellac treatment, as was the lowest O2, indicating anaerobic respiration. There were only minor differences among the other coating treatments; however, they were only sometimes different from those of the control, which generally had the highest O2, lowest CO2, and lowest ethanol. Shellac and the carnauba microemulsion also altered the volatile profile more than the control and the nanoemulsion did, especially for ‘Unique’ tangors. For ‘Unique’ tangors, the control and nanoemulsion ranked highest for tangerine flavor and had the least off-flavor at the end of storage. Among the coatings tested, the carnauba emulsions demonstrated less water loss, imparted more sustainable gloss, and caused less ethanol production than shellac, with the nanoemulsion exhibiting higher gloss measurements, less modifications of the atmosphere and volatile profile, and, consequently, better flavor compared with the microemulsion.

Utilization of Acacia auriculiformis seed (Akashmoni) oil – A new source for the synthesis of alkyd resin

An alkyd resin is prepared from a renewable raw material Acacia auriculiformis seed oil (ASO), which has a high content of linoleic acid. Long oil alkyd resins have been synthesized by alcoholysis followed by the poly-esterification method using oil, glycerol, pentaerythritol (PE), sorbitol, phthalic anhydride (PA), and maleic anhydride (MA) in proportions according to alkyd formula calculation. The various physicochemical properties of ASO like acid value, saponification value, iodine value, etc, and fatty acid composition were determined. Physico-chemical properties of alkyd resins like viscosity, acid value, nonvolatile matter, etc. were determined and compared with soybean oil-based alkyd resins. The structural characterization of the resins was carried out using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopic techniques. These resins were cured by drier and their film properties were determined. The drying properties of the alkyd resins had been improved remarkably in the case of ASO-based resin. The performance of coating film produced by these alkyd resins were characterized by drying time, gloss measurement, hardness test, cross-cut adhesion test, and chemical resistance test. Analysis of these alkyds proved that ASO can be used as a new potential raw material for surface coating application.

Change in Color and Gloss Parameters of Stained Monolithic Resin-Ceramic CAD/CAM Materials After Simulated Aging: An In Vitro Study.

To measure the effect of simulated aging on stained resin-ceramic CAD/CAM materials regarding the durability of color and gloss. Test specimens (n = 15 per material) were prepared out of CAD/CAM ingots from two resin nanoceramics (Lava Ultimate [LVU], Cerasmart [CER]) and a polymer-infiltrated ceramic (ENA, VITA Enamic) stained with the manufacturer's recommended staining kit using photopolymerization. Control specimens were made of feldspathic ceramic (VITA Mark II [VM2]) and stained by means of ceramic firing. Negative control specimens (n = 15) (no staining) were prepared for each group. Color and gloss measurements were performed before and after each aging cycle by means of mechanical abrasion with a toothbrush. Groups were compared using Kruskal-Wallis test and paired post hoc Conover test. Changes within a group were calculated using Wilcoxon signed-rank test (α = .05). The color difference (ΔE) was statistically significant for all stained CAD/CAM materials after simulated aging: CER (P < .001, 95% CI: 2.96 to 3.69), LVU (P = .004, 95% CI: 1.09 to 1.46), ENA (P = .004, 95% CI: 0.20 to 0.42), and VM2 (P < .001, 95% CI: 0.29 to 1.08). Aging resulted in a statistically significant increase in gloss in the LVU group (P < 0.001, 95% CI: 13.78 to 17.29), whereas in the ENA (P < .001, 95% CI: 7.83 to 12.72), CER (P < .001, 95% CI: 2.69 to 8.44), and VM2 (P = .014, 95% CI: 0.22 to 1.87) groups, a significant decrease in gloss was noted. Color and gloss of stained resin-ceramic CAD/CAM materials changed significantly after aging by means of toothbrush abrasion in vitro.

The Influence of Drying Conditions of Clay-Based Polymer Coatings on Coated Paper Properties

Coatings based on pigment and polymer binders are applied on paper surfaces to improve their surface, optical, and printing properties. Besides the coating composition, the structure and properties of the coated papers are influenced by the coating layer consolidation upon drying. In this study, the influence of drying conditions on the structure and properties of coating layers based on natural pigments (clay) and polymer binders (butadiene acrylonitrile latex) has been analyzed. Using a laboratory rod Mayer device, the coatings were applied as thin layer (about 15–16 g/m2) on the paper surface and samples of coated paper were dried at 20 and 105 °C temperatures. The optical, structural, and water absorption properties of the coating layer were evaluated by the measurement of gloss, opacity, void fraction, light scattering, and contact angle. The obtained results highlighted that both the drying temperature and latex content in the coating color have a synergic effect on the coated paper quality.

Composições de Solventes de Baixa Toxicidade para Formulação de Vernizes de Uso em Restauro

Varnishes consist basically of a resin and solvent. Aromatic solvents are widely used for varnish formulations, but they present considerable toxicity which requires their replacement. Two binary solvent systems with an oxygenated solvent (ethyl acetate or isoamyl acetate) and cyclohexane were studied as possible substitutes for xylene in varnish formulations. The toxicity of solvents was analyzed using data from the Globally Harmonized System of Classification and Labeling of Chemicals and the National Institute for Occupational Safety and Health. The solubility of Damar, Paraloid B72, Regalrez 1094, and Laropal K80 resins in these solvents was evaluated by Hansen and Teas Solubility Parameters, sigma profiles, and experimental method. Vapor pressure measurements were obtained from solvents and viscosity and gloss measurements from varnish formulations. The results indicated the potential of binary solvent systems as substitutes for xylene, but require further studies on their effects on pictorial materials on which they are applied.