scholarly journals Evaluation of the process thermal treatment of maple wood saturated water steam in terms of change of pH and color of wood

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2550-2559
Author(s):  
Ladislav Dzurenda ◽  
Anton Geffert ◽  
Jarmila Geffertová ◽  
Michal Dudiak
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Ph Value ◽  
Statistical Processing ◽  
Color Difference ◽  
Acer Pseudoplatanus ◽  
Water Steam ◽  
Saturated Water ◽  
Before And After ◽  
Total Color Difference

Changes in maple wood’s pH and color (Acer pseudoplatanus) were evaluated before and after thermal treatment process with saturated water steam. Maple wood was thermally treated at temperatures: tI = 105 ± 2.5 °C, tII = 125 ± 2.5 °C, and tIII = 135 ± 2.5 °C for τ ≤ 12 hours. Direct pH measurement of maple wood with a moisture content above the fiber saturation point (FSP) was performed using a pH-meter SI 600 with a Lance FET + H puncture probe. The polynomial dependence of pH and total color difference ∆E* on temperature t time τ was calculated by statistical processing of measured results. The correlation between the total color difference ∆E* of maple wood in the process of thermal color modification and the pH value is expressed y the equation: ∆E* = 4.5516∙(pH)2 – 48.405∙(pH) + 134.35. This dependence is a suitable tool for assessing the achieved color change based on the change of wood pH in the technological process.

scholarly journals Influence of UV Radiation on the Color Change of the Surface of Steamed Maple Wood with Saturated Water Steam

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 217
Author(s):  
Ladislav Dzurenda ◽  
Michal Dudiak ◽  
Eva Výbohová
Keyword(s):  
Uv Radiation ◽  
Color Change ◽  
Color Space ◽  
Color Stability ◽  
Color Difference ◽  
Saturated Steam ◽  
Water Steam ◽  
Saturated Water ◽  
Red Color ◽  
Uv Lamp

The wood of maple (Acer Pseudopatanus L.) was steamed with a saturated steam-air mixture at a temperature of t = 95 °C or saturated steam at t = 115 °C and t = 135 °C, in order to give a pale pink-brown, pale brown, and brown-red color. Subsequently, samples of unsteamed and steamed maple wood were irradiated with a UV lamp in a Xenotest Q-SUN Xe-3-H after drying, in order to test the color stability of steamed maple wood. The color change of the wood surface was evaluated by means of measured values on the coordinates of the color space CIE L* a* b*. The results show that the surface of unsteamed maple wood changes color markedly under the influence of UV radiation than the surface of steamed maple wood. The greater the darkening and browning color of the maple wood by steaming, the smaller the changes in the values at the coordinates L*, a*, b* of the steamed maple wood caused by UV radiation. The positive effect of steaming on UV resistance is evidenced by the decrease in the overall color difference ∆E*. While the value of the total color diffusion of unsteamed maple wood induced by UV radiation is ∆E* = 18.5, for maple wood steamed with a saturated steam-air mixture at temperature t = 95 °C the ∆E* decreases to 12.6, for steamed maple wood with saturated water steam with temperature t = 115 °C the ∆E* decreases to 10.4, and for saturated water steam with temperature t = 135 °C the ∆E* decreases to 7.2. Differential ATR-FTIR spectra declare the effect of UV radiation on unsteamed and steamed maple wood and confirm the higher color stability of steamed maple wood.

scholarly journals Changes in the Physical and Chemical Properties of Alder Wood in the Process of Thermal Treatment with Saturated Water Steam

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 898
Author(s):  
Michal Dudiak ◽  
Ladislav Dzurenda
Keyword(s):  
Thermal Treatment ◽  
Chemical Properties ◽  
Alnus Glutinosa ◽  
Color Difference ◽  
Average Density ◽  
Saturated Steam ◽  
Water Steam ◽  
Color Changes ◽  
Saturated Water ◽  
Range Of Values

The paper presents changes in color and selected physico-chemical properties of alder (Alnus glutinosa) wood during the process of thermal treatment of the wood with a saturated steam-air mixture or saturated water steam in the temperature range t = 95–125 °C for τ = 3 to 12 h. During the process of thermal treatment of alder wood, the original light white-gray color changes depending on the temperature and time of modification to soft reddish-brown to dark brown color shades. Color changes of alder wood expressed in the form of the total color difference are in the range of values ∆E* = 2.7–31.7. Measurements of the density of thermally treated alder wood in the dry state indicate that due to the thermal treatment of alder wood, the density decreases by ρ ≤ 4.6% compared to the average density of native alder wood. Due to the hydrolysis of hemicelluloses, in the process of thermal treatment of wet alder wood, its acidity changes in the range of values: pH = 4.9 to 3.1. Analyzes of ATR-FTIR spectroscopy indicate changes in alder wood extractants and hemicellulose degradation. A decrease in unconjugated and an increase in conjugated carbonyls was observed at all temperatures of thermal modification of alder wood. Measurements indicate changes in the lignin of alder wood and the fact that as the temperature increases, the formation of new carbonyls increases, which is reflected in the change of the chromophoric system.

scholarly journals Influence of thermal treatment on color change of beech wood with red heartwood

2016 ◽  
pp. 239-256
Author(s):  
Nebojsa Todorovic ◽  
Zdravko Popovic ◽  
Goran Milic ◽  
Ranko Popadic
Keyword(s):  
High Temperature ◽  
Thermal Treatment ◽  
Cross Section ◽  
Color Change ◽  
Beech Wood ◽  
Color Difference ◽  
Mean Values ◽  
Before And After ◽  
Section Surface ◽  
The Difference

The goal of this word was to examine the parameters of color of beech wood before and after thermal treatment, and to determine if there is a difference in color between sapwood and red heartwood before and after application of high temperature. Samples were treated at temperatures of 170?C, 190?C and 210?C, respectively, during 4 hours. Color coordinates (CIEL*a*b* system) were measured before and after treatment by using the following parameters: ?L, ?a, ?b and ?E - color change. Color was assessed at four spots on the radial and cross-section surfaces of wood and their mean values were taken for further calculations. Acquired results show that the applied heat treatment of sapwood did not significantly influence the change of color difference between cross-section and radial surfaces. The difference between cross-section and radial surfaces, in nontreated red heartwood was smaller than that measured in sapwood. The color difference of nontreated sapwood and red heartwood was more pronounced on the radial than on the cross-section surface. Application of high temperature caused a significant decrease of this difference. Temperature of 210?C caused the smallest color difference between these two parts of wood which was in this research determined on the radial surface. It was concluded that the applied thermal treatment almost equalized the colors of sapwood and red heartwood, especially on the radial surface, and from this aspect it can be concluded that these two parts of beech wood were completely equalized. It should also be noted that in the case of equalized properties, sapwood and red heartwood can be equally applied in a final product made of thermally treated beech wood.

Accelerated Aging Effects on Color Stability of Potentially Color Adjusting Resin-based Composites

2021 ◽  
Author(s):  
L Sensi ◽  
C Winkler ◽  
S Geraldeli
Keyword(s):  
Color Change ◽  
Test Chamber ◽  
Accelerated Aging ◽  
Color Stability ◽  
Color Difference ◽  
Composite Resins ◽  
Aging Effects ◽  
Commercial Resin ◽  
Before And After ◽  
Total Color Difference

SUMMARY The aim of this study was to compare the effects of accelerated aging on the overall color stability of potentially color adjusting commercial resin-based composite resins. Thirty specimens (10 mm diameter and 2.5 mm thick; n=6) were fabricated using five different materials: Estelite Omega, GC Kalore, Venus Pearl, Harmonize, and Omnichroma. Color measurements were taken for each sample using a spectrophotometer before and after submitting samples through the artificial aging process (Q-sun Xenon Test Chamber, 102 min light at 63°C black panel temperature; 18 min light and water spray per ASTM G155) for a total of 300 hours (12.5 days). The total color difference (ΔE*ab) was calculated using SpectraMagic NX software and analyzed using one-way analysis of variance and Tukey test. The results for color change (ΔE*ab) were statistically significant. Omnichroma and Venus Pearl presented superior color stability and the lowest overall color change, whereas GC Kalore and Harmonize presented significant color change that would be considered clinically unacceptable (ΔE*ab > 3.3).

scholarly journals Assessment of changes in color and color parameters of light-cured composite resin after alternative polymerization methods

2013 ◽  
Vol 07 (01) ◽  
pp. 110-116 ◽  
Author(s):  
Emine Sirin Karaarslan ◽  
Bulbul Mehmet ◽  
Ertas Ertan ◽  
Mehmet Ata Cebe ◽  
Aslihan Usumez
Keyword(s):  
Composite Resin ◽  
Color Change ◽  
Color Difference ◽  
Study Groups ◽  
Color Parameters ◽  
Color Changes ◽  
Yellow Color ◽  
Before And After ◽  
Total Color Change

ABSTRACTObjective:To examine the amount of change in color and color parameters of a composite resin (Filtek P60) polymerized by five different polymerization methods.Methods: A Teflon mold (6mm in diameter, 2mm in height) was used to prepare the composite resin discs (n=10). G1: Polymerization with inlay oven; G2: Polymerization with HQTH and autoclave; G3: Polymerization with LED and autoclave; G4: Polymerization with HQTH; G5: Polymerization with LED. Colorimetric values of the specimens before and after polymerization were measured using a spectrophotometer. The CIE L*a*b color system was used for the determination of color difference. Analysis of variance (ANOVA) was used to analyze the data for significant differences. Tukey’s HSD test and paired two-tailed tests were used to perform multiple comparisons (α=.05).Results: There were no significant differences in total color change (ΔE*ab) among the polymerization groups (P>.05). However, the lowest color change (ΔE*ab) value was 3.3 in LED and autoclave; the highest color change (ΔE*ab) value was 4.6 in HQTH. For all groups, CIE L*, C*ab and a*values decreased after polymerization (P<.05). The highest Δb* and ΔC*ab values were observed in specimens polymerized in an inlay oven (P<.05).Conclusion: Composite resin material showed color changes above the clinically accepted value in all study groups (ΔE*ab≥3.3). All specimens became darker during investigation (ΔL*< 0). Specimens polymerized with inlay oven presented the highest Δb* values which means less yellow color in specimens. (Eur J Dent 2013;7:110-116)

Preservation of Archaeological Leather by Reinforcement with Styrene Butadiene Rubber

2014 ◽  
Vol 1064 ◽  
pp. 15-20 ◽  
Author(s):  
Rushdya Rabee ◽  
Mona F. Ali ◽  
Abdel Gawaad Ali Fahmy ◽  
Sawsan Fakhry Halim
Keyword(s):  
Mechanical Properties ◽  
Ph Value ◽  
Protective Layer ◽  
Color Difference ◽  
Styrene Butadiene Rubber ◽  
Infrared Spectrometry ◽  
Butadiene Rubber ◽  
Elongation At Break ◽  
Before And After ◽  
Styrene Butadiene

Leather has been used in Egypt since 4000 BC. Ancient Egyptians used leather as shrouds, bookbinding and manuscripts. This research aims to find a way to protect archeological leather from damage by environmental factors, without losing their archaeological appearance. Leather samples were subjected to ageing in order to simulate archaeological leather. Styrene butadiene rubber was used to coat the leather samples. Then the leather samples were dipped (immersed) in a bath containing SBR dissolved in toluene with concentrations varies from 1 to 5% by weight. The effect of leather/ SBR reinforcement was evaluated by Fourier Transform Infrared Spectrometry (FTIR) and measuring the mechanical properties (tensile strength and elongation at break (%), color difference (ΔE) and lightness (L), pH value before and after ageing. In addition, Scanning Electron Microscope (SEM) was used to study the surface morphology of samples. Finally, all samples were subjected to ageing after reinforcement. The results revealed that reinforcement of leather samples by SBR solutions having concentration 3 % gave the best results among other concentrations. The mechanical properties of treated samples were enhanced with reduction in the ΔE values. The results also showed that the pH values of the treated samples did not change even after further aging. SEM scans evidenced that SBR filled the leather surface cracks besides the formation of a protective layer on the leather surface.

Color changes of ash wood (Fraxinus excelsior L.) caused by thermal modification in air and steam

2021 ◽  
Vol 116 ◽  
pp. 21-27
Author(s):  
Jakub Gawron ◽  
Monika Marchwicka
Keyword(s):  
Color Space ◽  
Color Difference ◽  
Thermal Modification ◽  
Fraxinus Excelsior ◽  
Space Model ◽  
Color Changes ◽  
Cielab Color Space ◽  
Before And After ◽  
Total Color Difference ◽  
Cielab Color

Color changes of ash wood (Fraxinus excelsior L.) caused by thermal modification in air and steam. Ash wood samples of 20x20x30 mm were subjected to thermal modification in different conditions. The thermal modification was conducted in air at 190 °C and in steam at 160 °C. For both environments modification lasted 2, 6 and 10 hours. Samples color parameters were measured before and after thermal modification on the basis of the mathematical CIELab color space model. Changes in all parameters (L, a and b) were observed, the highest in lightness (L) - darker color. The total color difference (ΔE) and chromaticity change (ΔC) were calculated for all samples. The highest value of ΔE was obtained for wood modified in the air at 190 °C for 10 h. The highest value of ΔC was obtained for wood modified in steam at 160 °C for 10 h. However, the value obtained for wood modified in the air at 190 °C for 10 h were only slightly lower.

scholarly journals Novel Color Change Film as a Time–Temperature Indicator Using Polydiacetylene/Silver Nanoparticles Embedded in Carboxymethyl Cellulose

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2306
Author(s):  
Aphisit Saenjaiban ◽  
Teeranuch Singtisan ◽  
Panuwat Suppakul ◽  
Kittisak Jantanasakulwong ◽  
Winita Punyodom ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Electron Micrographs ◽  
Carboxymethyl Cellulose ◽  
Fruits And Vegetables ◽  
Color Change ◽  
Color Difference ◽  
Scanning Electron Micrographs ◽  
Transmission Electron ◽  
Kinetics Of ◽  
Total Color Difference

Time–temperature indicators (TTIs) can be important tools in product applications to monitor food quality losses, especially for fruits and vegetables. In this context, the effects of silver nanoparticles (AgNPs) and glycerol on the color change of polydiacetylene/AgNPs (PDA/AgNPs) embedded in carboxymethyl cellulose (CMC) film as time–temperature indicators (TTIs) were investigated. A CMC film prepared with 30 mg/L AgNPs and a 1:3 (v/v) PDA:AgNP ratio exhibited a faster color change than under other conditions. At 35 °C, the films with PDA/AgNPs changed color from purplish-blue to purple and purple to reddish-purple over time due to the higher thermal conductivity of AgNPs and larger PDA surface area exposed to specific temperatures. The total color difference (TCD) of PDA/AgNP-embedded CMC film directly changed with regard to time and temperature. However, adding glycerol to the system resulted in a symmetrical chemical structure, a factor that delayed the color change. Scanning electron micrographs showed AgNPs embedded in the CMC films. Transmission electron micrographs indicated a core-shell structure of PDA/AgNP vesicles in the CMC matrix. PDA/AgNP vesicles were confirmed by second derivative Fourier transform infrared spectroscopy, with a new peak at 1390–1150 cm−1. The kinetics of TTIs from PDA/AgNP-embedded CMC films yielded an activation energy of 58.70 kJ/mol.

scholarly journals The Influence of Drying Temperature on Color Change of Hornbeam and Maple Wood Used as Surface and Inner Layers of Wood Composites

2021 ◽  
Vol 11 (22) ◽  
pp. 10673
Author(s):  
Ivan Klement ◽  
Peter Vilkovský ◽  
Tatiana Vilkovská ◽  
Kazimierz A. Orłowski ◽  
Jacek Barański ◽  
...  
Keyword(s):  
High Temperature ◽  
Color Change ◽  
Color Difference ◽  
Wood Composites ◽  
Drying Temperature ◽  
Color Coordinates ◽  
Color Changes ◽  
Hot Air ◽  
Two Phases ◽  
Total Color Difference

The thermal treatment of wood changes its structure due to the degradation of wood polymers (cellulose, hemicellulose and lignin), so the physical properties of wood are either improved or degraded. Color changes apply not only to natural wood, but also to such wood composites for which some amount of glue is used in their construction (e.g., plywood, blockboard or laminboard). This article is focused on the analysis of hornbeam and field maple wood color changes influenced by drying temperature. Two types of drying modes were used: hot-air mode where the temperature of the drying environment was 60 °C, and high-temperature mode with a drying temperature of 120 °C. The drying mode was divided into two phases depending on the moisture content of the wood. The compared woods had similar values of color coordinates at the beginning of drying. During hot-air drying, the largest changes in color coordinates occurred during the first 24 h. The total color difference between the color at the end and the beginning of drying was 7.3 for hornbeam and 11.1 for maple. The overall color difference between the compared woods was minimal. During high-temperature drying (120 °C), the color changes of the dried woods were more pronounced. In the case of maple wood, there was a very significant change in color and the value of ΔE* was twice as high as for hornbeam. The total color difference between the color at the end and at the beginning of drying was 8.7 for hornbeam and 18.9 for maple.

scholarly journals Effect of Different Polishing Systems and Drinks on the Color Stability of Resin Composite

2013 ◽  
Vol 14 (4) ◽  
pp. 662-667 ◽  
Author(s):  
Sevil Gurgan ◽  
Asll Berber ◽  
Filiz Yalcin Cakir ◽  
Meserret Baseren
Keyword(s):  
Color Change ◽  
Resin Composite ◽  
Sour Cherry ◽  
Color Stability ◽  
Color Difference ◽  
Mean Values ◽  
Color Changes ◽  
Storage Solutions ◽  
Before And After ◽  
Cherry Juice

ABSTRACT Aim The purpose of this study was to evaluate the color stability of resin composit using different finishing systems and drinks. Materials and methods Composit disks (5 mm diameter, 2 mm thickness) were prepared for each nanofilled composite using a brass mold. The specimens were divided into 5 finishing system groups Mylar strip (Mylar, DuPont, Wilmington, Del., USA), Soft Lex (3M™ ESPE™ St. Paul, MN, USA), Enhance (Dentsply-DeTrey GmbHD Konstanz, Germany), Hiluster (KerrHawe, Bioggio, Switzerland), Opti Disc (KerrHawe, Bioggio, Switzerland) and each group was divided into 10 subgroups (n = 10) and stored for 24 hours at 37°C in different drinks water coffee, coffee with sugar, tea, tea with sugar, diet coke, coke, light sour cherry juice or sour cherry juice. Color of all specimens was measured before and after exposure with a spectrophotometer using CIE L*a*b* relative, and color changes (ΔE*) were then calculated. The data were analyzed with a twoway analysis of variance (ANOVA), and mean values were compared by the Tukey HSD test (p = 0.05). Results For the drinks, the lowest ΔE* values were observed in the water and highest ΔE* values were observed in sour cherry juice. When drinks with and without sugar were compared, all groups with sugar demonstrated a higher color difference than without sugar. For the different finishing systems, Mylar strip group demonstrated signicantly highest color change; Enhance groups demonstrated signicantly lowest color change. Conclusion Finishing treatments and storage solutions significantly affect the color stability of resin composite. The presence of sugar in drinks increased the color difference compared to drinks without composit. Clinical significance Polishing techniques and drinking drinks with sugar may affect the color of esthetic restorations. How to cite this article Berber A, Cakir FY, Baseren M, Gurgan S. Effect of Different Polishing Systems and Drinks on the Color Stability of Resin Composite. J Contemp Dent Pract 2013; 14(4):662-667.

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