Matte Surface Research Articles

Retouching matt contemporary paint layers: a new approach using natural polymers

Different painting techniques, materials and application methods that characterise contemporary artworks, with predominantly matt surfaces and uniform tones, make retouching one of the most complicated conservation treatments, since sameness is the main target. The retouching intervention carried out at the Galleria Nazionale d’Arte Moderna e Contemporanea in Rome on Tempi prospettici (1969), an installation by the Italian artist Carlo Alfano, gave the opportunity to investigate a method to obtain different matt/glossy values through the use of natural polymers as binders. The binders chosen (different polysaccharides, cellulose derivatives and isinglass) were analysed, both individually and mixed, through colorimetric and glossmetric measurements. The pigment-binder ratio and the addition of silica to get a modulation of the matt appearance of paint formulations were also evaluated. The comparation of the colorimetric values of painting samples and those of the original paint led to the identification of the best solution for the retouching of the artwork

Investigation of Parameters That Affect the Acquired Near Infrared Diffuse Reflected Signals in Non-Destructive Soluble Solids Content Prediction

Near infrared spectroscopy is a susceptible technique which can be affected by various factors including the surface of samples. According to the Lambertian reflection, the uneven and matte surface of fruits will provide Lambertian light or diffuse reflectance where the light enters the sample tissues and that uniformly reflects out in all orientations. Bunch of researches were carried out using near infrared diffuse reflection mode in non-destructive soluble solids content (SSC) prediction whereas fewer of them studying about the geometrical effects of uneven surface of samples. Thus, this study aims to investigate the parameters that affect the near infrared diffuse reflection signals in non-destructive SSC prediction using intact pineapples. The relationship among the reflectance intensity, measurement positions, and the SSC value was studied. Next, three independent artificial neural networks were separately trained to investigate the geometrical effects on three different measurement positions. Results show that the concave surface of top and bottom parts of pineapples would affect the reflectance of light and consequently deteriorate the predictive model performance. The predictive model of middle part of pineapples achieved the best performance, i.e. root mean square error of prediction (RMSEP) and correlation coefficient of prediction (Rp) of 1.2104 °Brix and 0.7301 respectively.

Microstructural response of copper foil to a novel double-cross rolling process

Bending resistance is regarded as a significant factor in achieving the widespread application of copper foils. This paper proposed a novel double-cross rolling process, which improved the bending fatigue life of copper foils by as much as 101% in comparation with conventional rolling. In this study, an investigation was conducted into the effects of double-cross rolling on the microstructure and texture of copper foils and the strengthening mechanism during the bending test was discussed. Results show that double-cross rolling could change the deformation behavior on bright and matt surfaces, resulting in equiaxed grains on both surfaces and some fine grains. Both surfaces were dominated by Brass and S textures, which can be attributable to from non-uniform and shear deformation respectively. Weak Goss and Cube textures resulted from the fine grains remaining after heat treatment. After double-cross rolling, the strain induced subgrains of copper foils facilitated the migration of grain boundary and grain rotation, thus improving bending property.

Modelling and Experimental Investigation of Luminous Coupling in UVLED Driven Optical Fiber Reactors

Background: Photocatalytic oxidation is a promising tool for waste water treatment and decomposition of biologically non digestible substances. Immersed nanoscale catalyst particles from semiconductor materials such as TiO2 and ZnO can be excited by absorbed UV radiation, leading to hydroxyl-ion formation at the surface of the semiconductor and oxidative degradation of pollutants. Objective: This contribution deals with reactors equipped with catalyst coated light guides to combine the advantages of immobilized catalysts with nearly homogeneous irradiation. With experimental and theoretical methods the coupling and decoupling of radiation were investigated and the performance of catalyst coated light guides was tested by means of methylene-blue degradation. Methods: Radiation models, known from the recent literature, use single ray, parallel ray or multi ray models to approximate the light transmission. These models neglect Fresnel reflection and consider only coupling into the light guide. In this study, the LED was simulated as a Lambertian radiator using 10 4 rays with angle dependent intensities. This well-known model was extended with Fresnelreflection, which predicted the measured coupling efficiencies accurately. The simulations predict the decoupling and catalyst activation at the lateral surface of the light guide for two boundary cases, ideal matt and ideal reflective surfaces. To generate matt surfaces, the light guides were either scratched or coated with TiO2 p25 nanopowder. Sol-gel coating methods were used, to create reflective surfaces. Results: When using matt surfaces, the decoupling rate is very high: 80% of the radiant flux exits the light guide in less than 10 cm. If light guides with reflective surfaces are used, the radiant flux leaving the light guide is low: less than 10% of the radiation exited the light conductor in the first 10 cm. Methyleneblue degradation, seen as a model reaction, was used to determine the reactor performance by comparing the pseudo first order reaction coefficients. Due to the uniform light distribution along the length of the light guides and the resulting even formation of reactive radicals, the quantum yield was increased by a factor of 3, using sol-gel coated light guides, rather than powder coated light guides. Conclusion: The effectiveness of LED driven optical fiber reactors was intensified, if reflective surfaces are used instead of matt surfaces. These surfaces are achieved by sol gel chemistry. However, to use the complete amount of photons, which entered the optical fiber, very long light guides are needed.

Accurate electronic transport characterization of B+ ion-implanted silicon wafers with self-normalized nonlinear photocarrier radiometry

A self-normalized photocarrier radiometry (PCR) is proposed to characterize the electronic transport properties (minority carrier lifetime, carrier diffusion coefficient, and surface recombination velocity) of B+ ion-implanted silicon wafers via multi-parameter estimation. In self-normalized PCR the amplitude and phase measured from the implanted surface are normalized by that measured from the matte rear surface (non-implanted substrate) of the ion-implanted silicon wafer to eliminate the need to measure the instrumental frequency response which is a major error source of the multi-parameter estimation. Two- and single-layer nonlinear PCR models are employed respectively to describe the PCR signals measured from the implanted and matte rear surfaces of the wafers. The self-normalized PCR is applied to the simultaneous determination of the electronic transport parameters and the thickness of the implanted layer of the ion-implanted silicon wafers. Experimentally, the frequency dependences of PCR amplitude and phase measured from the implanted and rear surfaces under 830-nm excitation at 40.5 mW are measured for seven B+ ion-implanted silicon wafers with different implantation doses. The electronic transport parameters and thicknesses of the implanted layers are then determined by multi-parameter fitting the self-normalized PCR amplitude and phase to corresponding nonlinear PCR models, as well as determined by the conventional PCR via measuring the instrumental frequency response and subtracting its influence on the measured PCR signals of the ion-implanted wafers for comparison. The lower variances of multi-parameter fitting and improved uncertainties of the fitted transport parameters in the self-normalized PCR as compared to that in the conventional PCR corroborate the improved accuracy and reliability of the self-normalized PCR for the simultaneous determination of the electronic transport parameters of ion-implanted silicon wafers.

Confecção e Análise de um Piranômetro Fotovoltaico de Baixo Custo

The present research aimed the development and the evaluation of a low cost photovoltaic pyranometer, built from easily found materials in the national market. Therefore, models of small polycrystalline silicon photovoltaic modules were evaluated. A pyranometer body prototype with was developed with machined engineering plastic. Also, the behavior of diffusers built with three different materials Thecnyl®, acrylic and polyvinyl chloride were analyzed. For the chosen one, two distinct thicknesses were tested, as well as polished and matte surface finishing. All the tests were performed in the field, in the Federal University Rural of Semiarid weather station, from Mossoro-RN, between 2017 august and 2018 march. The prototypes results were compared to a secondary class reference pyranometer. The experiments data were collected by an automatic datalogger and its handling was accomplished considering the regulation ISO 9847:1992 recommendations. The prototype final model has shown a satisfactory performance considering measurements in the hourly and daily scales. In the total hourly values measurements, considering the interval of 6 a.m. to 6 p.m., the absolute percentage relative error was 2,26%, the minimum was 0,433% and the maximum was 8,10%. In the total daily values, the absolute percentage relative error was 0,50%, the minimum was 0,16% and the maximum was 0,93%.

The Selection of Ribes nigrum L. and Grossularia reclinata Mill. Based on Distant Hybridization

In this study, 1921 flower were pollinated, 484 hybrid seeds were sown, of which 41 plants were cultivated only on 6 crossing combinations. The analysis of the formed hybrid fruits and seeds of Gr. reclinata × R. nigrum showed that the fruit weight varies between 3.5–4.5 gr, the shape is round-oval, the diameter is more than 20 mm, and the color is maroon. The number of seeds per berry varies from 6 to 19. Germination of hybrid seeds is low (7.9–8.3%). Their germination is not even. In the crosses, R. nigrum × Gr. reclinata formed round, black fruits, weighing up to 1.7 gr. The number of seeds per fruit ranges from 8 to 34. Seed germination is low—from 25.6 to 29.6%. Black currant hybrids Gr. reclinata × R. nigrum inherited partial pubescence of rhachis of flower raceme, matte surface of lamina, and smooth ovary; the cylindrical shape of hypanthium and pubescence on the stile of pistil are inherited from gooseberries. The problems of the use of distant hybridization in the selection of black currants and gooseberries are considered. The hybrids of R. nigrum × Gr. reclinata are obtained. It is found out that reciprocal amphihaploids differ from the original parental forms. Stable infertility does not allow using them with practical purposes.

Preparation and Characteristics of Titanium Silicate Filler for Functional Materials

During the interaction of titanite with hydrochloric acid, a composite titanosilicate precipitate (TSP) of the composition TiO2 ⋅ (1.1–1.15) SiO2 ⋅ (0.8–0.85) H2O consisting of two phases is isolated—crystalline titanium dioxide of rutile modification and silica. It has been found that, during high-temperature treatment (850°C), particles of the hydrated precipitate condense with an increase in crystallinity and a decrease in Ssp almost twofold compared to freshly precipitated TSP, without sintering of particles and formation of new phases. Particles of the resulting composition are agglomerates of fragments of a fairly regular shape, which is characteristic of crystalline particles of titanium dioxide, the surface of which is coated with an amorphous silica shell. The study of the samples using an electron microscope and a laser analyzer showed that 90% of the particles are represented by a fairly narrow fraction 0.4–1 μm in size. The morphological properties of the particles of the composition, as well as its technical characteristics, including the ability to give a matte surface to transparent organic dispersions, allow one to conclude the prospects of its use as an effective filler in the manufacture of adhesives and sealants with dielectric properties and increased heat resistance. In addition, such a filler may find application in the manufacture of other functional materials.

Depth Information Enhancement Using Block Matching and Image Pyramiding Stereo Vision Enabled RGB-D Sensor

Depth sensing devices enabled with an RGB camera, can be used to augment conventional images with depth information on a per-pixel basis. Currently available RGB-D sensors include the Asus Xtion Pro, Microsoft Kinect and Intel RealSense <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">™</sup> . However, these sensors have certain limitations. Objects that are shiny, transparent or have an absorbing matte surface, create problems due to reflection. Also, there can be an interference in the IR pattern due to the use of multiple RGB-D cameras and the depth information is correctly interpreted only for short distances between the camera and the object. The proposed system, block matching stereo vision (BMSV) uses an RGB-D camera with rectified/non-rectified block matching and image pyramiding along with dynamic programming for human tracking and capture of accurate depth information from shiny/transparent objects. Here, the IR emitter generates a known IR pattern and the depth information is recovered by comparing the multiple views of the focused object. The depth map of the BMSV RGB-D camera and the resultant disparity map are fused. This fills any void regions that may have emerged due to interference or because of the reflective transparent surfaces and an enhanced dense stereo image is obtained. The proposed method is applied to a 3D realistic head model, a functional magnetic resonance image (fMRI) and the results are presented. Results showed an improvement in speed and accuracy of RGB-D sensors which in turn provided accurate depth information density irrespective of the object surface.

THE CASE TREATMENT OF CYSTADENOMA OF THE PANCREAS

Summary. Introduction. Cystadenoma of the pancreas is a benign tumor in the form of a cyst of epithelial origin, which in the absence of adequate treatment disrupts the function of the pancreas, due to compression on nearby tissues, and in 3 % of cases regenerates into cystadenocarcinoma.&#x0D; Aim. Present a clinical case of surgical treatment of cystadenoma of the body of the pancreas, while preserving the caudal part of the latter to prevent the possible development of diabetes.&#x0D; Material and methods. Patient M., 72 years old, who was hospitalized in the infectious department of the central district hospital, during ultrasound of the abdominal cavity and peritoneal space revealed a neoplasm of the retroperitoneal space in the body and tail of the pancreas, in connection with which she was transferred to the surgery department. After the appropriate examination, the patient underwent surgery — laparotomy. Removal of a neoplasm of the body of the pancreas. Distal pancreatojejunoanastomosis, entero-enteroanastomosis. Abdominal drainage.&#x0D; Results. The postoperative period was without complications, drainage was removed, sutures were removed for 9-10 days, the wound healed with primary tension.&#x0D; In the section of the drug, there is a capsule with a wall thickness of up to 2.0 mm, which contains mucopurulent masses in the form of flakes. The outer wall of the capsule is covered with joints and vessels, and the inner has a shiny matte surface. The histopathological examination indicates cystadenoma of the pancreas.&#x0D; The choice to form a distal pancreatojejunostomy in contrast to the distal resection of the pancreas was due to the patient’s age and high probability of developing diabetes because it is in the caudal part of the pancreas is the lion’s number of islets of Langerhans.&#x0D; Conclusion. When performing radical surgical interventions on the pancreas in elderly and senile patients, it is necessary to preserve the tissues of the latter, especially the tail, to prevent the development of diabetes.

The impact of wollastonite and dolomite on chemical durability of matte fast-fired raw glazes

Controlled share of wollastonite and dolomite in the recipe was decisive for achieving raw glazes with a matte surface in a fast-firing process. The surface characteristics were studied for 25 experimental glazes containing 9–39 wt% wollastonite and 0–16 wt% dolomite. The glaze suspensions were applied on raw tiles and fired to 1215 °C in an industrial kiln. The chemical durability of the tiles was measured according to the standard ISO 10545-13. Further, the impact of exposure time on surface degradation was measured for 0.1 and 3 vol% HCl-solutions. The changes in the phase composition were studied with SEM/EDXA and XRD. The surface consisted of wollastonite and diopside, some residual quartz and corundum as well as amorphous phases. Wollastonite crystals severely decreased the durability while diopside crystals provided a durable matte surface. The results give guidelines for manufacturing matte and chemically durable fast-fired raw glazes.

FTIR surface analysis for conservation

Several FTIR techniques are surface-sensitive. This sensitivity can be utilized to help with a wide range conservation issues. Examples from object degradation studies, conservation materials performance assessment and monitoring are presented. These are used to discuss the issues, advantages and information that can be drawn from studies. Glass degradation was quantified on the surfaces of cover glasses from important Nineteenth century daguerreotypes using Germanium attenuated total reflectance. The very limited information depth endowed by the high refractive index crystal gave good sensitivity when other techniques such as sectioning and scanning electron microscopy had failed to detect a gel layer present. The inner glass surface was always more deteriorated and the degree of deterioration inversely correlated with the distance between the inner glass surface and the daguerreotype or brass matt surface. Reflection–absorption FTIR microscopy has been combined with an excimer laser to determine the water content of a series of sections through the depth of a wax. A common wax used to protect metals has been found to take up liquid water in humid environments and hold that water close to or at the metal surface. An adjustable height gold mirror was used to bounce the IR beam many times across a surface, which can give extreme sensitivity. Haze and smoke generators are increasingly being introduced into displays or for special events or filming. Very low detection limits (1 ng) were found using gold coated glass slides to detect haze deposits.

How direct light and diffusive light influence the appearance of objects?

Shape, texture and light are crucial factors to determine the appearance of object. Recently, lighting environment has become diversified due to the improvement of lighting technology and it is important to consider the appearance of objects under various lighting conditions. Our previous study showed that the diffuseness of lighting influenced the perceived glossiness and roughness of an object (ICVS2017). In this study, we investigate the influence of direct light and diffusive light to the appearance of surface properties of an object. A miniature room was illuminated by a mixed lighting with directional light and diffusive light We used two LED lamps and a diffuser board. One was far from the diffuser board, giving a diffusive lighting condition. The other was close to the diffuser boards, giving a direct lighting condition. We tested five lighting conditions by changing the intensity ratio of each lamp. The test samples were made with a 3D printer. We used glossy and matte square samples with sine-wave surface which depth were 1.0 and 0.5 mm and three types of frequencies. Observers adapted to the illumination of the miniature room for one minute, and then responded the roughness and glossiness of the test samples using a magnitude estimation method. As a result, samples tended to appear less glossy and smoother as the lighting became more diffusive. Perceived glossiness showed clearer influence of lighting conditions for glossy and high-frequency-surface samples. Perceived roughness showed clearer influence of lighting conditions for matte surface samples.

Roman window glass in Hispania Baetica: Glass origin and manufacture study through electron microprobe analysis

Twenty five samples of Roman window glass of some archaeological sites situated in the Roman province Baetica: Acinipo (Ronda, Málaga), Carmo (Carmona, Seville), Herrera (Seville), Astigi (Écija, Seville), Cortalago (Minas de Riotinto, Huelva) and Torreparedones (Baena, Córdoba), were selected for Microprobe Analysis (EPMA). All of them are window glasses glossy/matte, manufactured by cooled and stretch processes. The aim of this study is to know aspects related to chemical composition of the glasses, the glass origin used in their production and manufacture processes of a typology of glass that is virtually unknown in the South of Hispania. The results reflect that all of them are silica-soda-lime glasses with compositions near to blue-green glasses typical of Roman times. However, except two samples, the group shows a feature unusual in other Roman glasses analysed: high manganese and low iron levels. The comparison with other similar samples of the same period, allows to hypothesize that an origin in the Levantine coast would be possible for the glasses used in the window panes studied. Related to the manufacture processes of these panes, chemical analysis in different areas of the same fragment reveal that panes are not homogeneous. Potassium small changes near to the matt surface of the panes could be associated with their manufacture.

Застосування рослинних ефірних олій для покращення якості повітря аудиторій університету

Аналіз забруднення повітря мікроорганізмами в навчальних та дослідження антимікробної активності рослинних ефірних олій для покращення екологічного стану аудиторій. Методи дослідження: Для встановлення загальної кількості мікроорганізмів та оцінки забруднення повітря було використано Седиментаційний метод (чашковий метод Коха). Колонії мікроорганізмів підраховувалися за правилом В.Л. Омелянського. Статистичну обробку даних проводили за допомогою програмних пакетів Microsoft Office Excel з достовірністю 95%. Показники стандартних відхилень обчислювали за загальноприйнятими формулами. Морфологію клітин вивчали на мікроскопі «Мікмед-2» (збільшення ×1500). Вплив рослинних ефірних олій на обрані штами мікроорганізмів (Staphylococcus aureus УКМ Б-904, Pseudomonas aeruginosa УКМ Б-907, Escherichia coli УКМ Б-906) оцінювали за допомогою диско-дифузійного методу. Результати: Під час досліду були виділені круглі, білі, жовті з матовою або блискучою поверхнею та рівним краєм колонії мікроорганізмів. За морфологічними ознаками мікроорганізми виявилися грамнегативними паличками або грампозитивними коками. Було встановлено, що ефективність рослинних ефірних олій проявляється у малих концентраціях і змінюється не суттєво при її збільшені. При вивченні антимікробної активності ефірних олій диско-дифузійним методом визначено, що ефірні олії лаванди та евкаліпту мали антибактеріальну активністю по відношенні до всіх досліджуваних штамів. Висновки: Досліджено, що рослинні ефірні олії (ялівцева, лавандова, евкаевкаліп та їх композиція) зменшує кількість мікроорганізмів в повітрі навчальних аудиторій в концентраціях 5-15 мкм/м3 і можуть бути ефективним засобом оздоровлення мікрофлори повітря приміщень. За результатами досліджень можна рекомендувати використовувати рослинні ефірні олії лаванди та евалкапту в концентраціях 5 мкл/м3 повітря після занять.

Attaining Natural Stone Appearance via Colored and Self-glazed Ceramics Stoneware Applied to Ceramics Tiles

There is a clear common lack of external architecture for its aesthetic appearance, and the design of the ceramic roof and the techniques applied to it are considered aesthetic input and value added to the design of ceramic surfaces in the external architecture. Also, exploiting new forming methods to produce self-glazed stone ceramic objects can be produced industrially. Likewise, the lack of a study linking the appearance of porcelain and natural stones.The research aims to legalize the relationship between stone porcelain fixtures and the aesthetic appearance of natural stones so that we reach the appearance of natural stones, which has become common in most ceramic tile products, and the link between it and stone porcelain techniques such as body coloring and self-vitrification to reach a scientific classification suitable for this relationship.The importance of the research lies in the fact that the appearance of natural stones is one of the sources of inspiration for designers in the manufacture of ceramic tiles. In the range of different shades.The research included many techniques such as the use of colored stone ceramic objects and mixing between colors, the use of the technique of glazed objects, to combine the glossy and matte surface, and the exploitation of different granular sizes to obtain the appearance of some natural stones.

Electrical Characteristics of Solder-Free SiC Die/Metal Foil/AlN Plate Junctions Fabricated Using Surface Activated Bonding

In conventional power device modules, Si-based dies are attached to metal layers on ceramic plates by using solders. Given that power devices made of widegap materials such as SiC and GaN are going to be launched into market, packaging technologies that exploit their superiority are strongly sought for. Solder-free modules, i.e., modules with dies directly bonded to metal layers on ceramic plates are likely to be ideal since fracture in the solder layer is one of the essential factors that limit the thermal tolerance of conventional power modules. In this work, we fabricated an SiC die/metal/ceramic plate junction by using surface activated bonding (SAB) and examined its current-voltage (I-V) characteristics at elevated temperatures. As ceramics AlN was used since the thermal expansion coefficient of AlN is close to that of SiC. The metal layer on AlN plate was made of an Al foil.We prepared a 635-μm-thick AlN ceramic plate and a 30-μm-thick Al foil. The average roughness (Ra) of the surface in AlN plate was ∼0.5 μm. Ra of the Al foil was 0.06 and 0.19 μm in its mirror and matte surfaces, respectively. The matte surface of Al foil was directly bonded to the AlN plate through a surface activation process using an Ar fast atom beam. In a preparatory study we fabricated an AlN/Al foil/AlN junction by bonding AlN plates to the both sides of an Al foil. We observed the cross section of AlN/Al foil/AlN junction by using scanning electron microscopy. We found that the AlN plate and Al foil were bonded to each other without gaps at the both AlN/Al interfaces although Ra of AlN plates and Al foils was much larger than typical Ra of semiconductor substrates that were bonded using SAB (≤~1 nm). We prepared an SiC epi substrate by growing an n+-SiC buffer layer and an n--SiC epi layer on an n+-4H-SiC (0001) substrate. We formed an ohmic contact on the backside of the epi substrate by evaporating an Al/Ni/Au and annealing at 1000 °C. Then we made a 300-μm-ϕ Ni/Au Schottky contact on the top by evaporation and lift-off. An Al layer was evaporated on the top of ohmic contact so that an SiC Schottky diode die was fabricated. Then the Al surface of ohmic contact of SiC die was bonded to the mirror surface of Al foil on AlN plate using SAB. Note that no intermediate layers such as solder were inserted at bonding interfaces.We measured the I-V characteristics between the Schottky contact of SiC die and the surface of Al foil at temperatures between room temperature and 300 °C. A reverse-bias current was ~10-7 A/cm2 at a reverse-bias voltage up to 6 V for temperatures lower than 250 °C. A larger reverse-bias current (~10-6 A/cm2) was observed in measurement at 300 °C. In the forward characteristics, lower turn-on voltages and larger series resistances were observed for higher temperatures. It is notable that these features are typically observed for Schottky diodes. In addition, no change was observed in appearance of the SiC die/Al foil/AlN junction even after the measurement at 300 ℃. Although the bonding strength in Al foil/AlN interfaces is still unclarified, these results suggest that SAB technologies could be useful for realizing solder-free modules of power devices.Acknowledgment—The Al foil employed in the work was supplied from Toyo Aluminium K.K. Figure 1

17.3: Black Photoresist Achieving Patterns with Extremely Low Reflection and Smooth Line Edge

This paper introduces a new type of black photoresist with a very low reflectance and very smooth pattern line edge that doesn't require adding micron‐size particles. Combinations of poor solvent, good solvent, and selected special substances as solutes in the black photoresist can achieve matte surface during drying process. Because particles are not used to achieve matte surface, the line edge will be very smooth. This photoresist is likely appropriate for applications where light reflection or light scattering should be avoided, such as black matrix and smartphone camera surroundings.

Synergistic Effect of Addition of Fillers on Properties of Interior Waterborne UV-Curing Wood Coatings

A waterborne ultraviolet (UV)-curing coating was prepared on the surface of wood materials with modification of talcum powder and calcium carbonate (CaCO3). When the waterborne UV-curing coatings on the surface of wood materials (WUVCW) was radiated for 1 min by UV (λ = 365 nm) and dried at 40 °C for 10 min, it showed good hardness, adhesion, and impact strength, with controlling the talcum content of 2.0% and CaCO3 content of 1.0%, respectively. When the content of talcum powder was higher than 2%, the mechanical properties and gloss of the WUVCW decreased, and when the talcum powder of WUVCW increase to more than 5%, a matte surface appeared after curing. When CaCO3 and talcum powder were present at the same time, the mechanical properties of WUVCW were better than those of only CaCO3 or talcum powder.

Tuning roughness and gloss of powder coating paint by encapsulating the coating particles with thin Al2O3 films

In this work, we report a method to change the surface finish of a standard polyester-based powder coating paint, from gloss to matt, by depositing ultrathin films of Al2O3 on the powder coating particles. The coating experiments were performed in a fluidized bed reactor at 1bar and 27°C, using a gas-phase coating process of alternating exposure of the particles to the two precursors (trimethylaluminium and water), similar to atomic layer deposition (ALD). We varied the number of coating cycles (1, 2, 3, 5, 7 and 9cycles) to obtain film thicknesses of the alumina shell ranging from 1 to 30nm. The average growth per cycle of the process is 3.5nm, significantly larger than the one for pure self-limiting ALD. When the average alumina shell was thicker than 6nm, the shell prevented the flow of the core particles, even though the powder particles did soften above the glass transition temperature. With the particles morphology intact, this resulted in a rough and matte surface finish of the coating after curing. The surface roughness, with a value around 9μm determined by surface profilometry, is associated to the alumina coated particles as observed with SEM and EDX analysis. In addition, the matte finish coating showed mechanical resistance similar to that of uncoated powder particles.