scholarly journals Treatment of wood with atmospheric plasma discharge: study of the treatment process, dynamic wettability and interactions with a waterborne coating

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jure Žigon ◽  
Matjaž Pavlič ◽  
Pierre Kibleur ◽  
Jan Van den Bulcke ◽  
Marko Petrič ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Treatment Process ◽  
Beech Wood ◽  
Treated Wood ◽  
Plasma Discharge ◽  
Contact Angles ◽  
Atmospheric Plasma ◽  
Waterborne Coating ◽  
Spruce Wood ◽  
The Impact

AbstractPlasma treatment is becoming a mature technique for modification of surfaces of various materials, including wood. A better insight in the treatment process and the impact of the plasma on properties of wood bulk are still needed. The study was performed on Norway spruce and common beech wood, as well as their thermally modified variations. The formations of the airborne discharge, as well as mass changes of the treated wood, were monitored. The impact of such treatment on wood-coating interaction was investigated by evaluating the dynamic wettability and penetration into wood. At the wood surface, plasma streamers were observed more intense on denser latewood regions. Wood mass loss was higher with increasing number of passes through the plasma discharge and was lower for thermally modified wood than for unmodified wood. Plasma treatment increased the surface free energy of all wood species and lowered the contact angles of a waterborne coating, these together indicating enhanced wettability after treatment. Finally, the distribution and penetration depth of the coating were studied with X-ray microtomography. It was found that the coating penetrated deeper into beech than into spruce wood. However, the treatment with plasma increased the penetration of the coating only into spruce wood.

scholarly journals Improvement of Heat-Treated Wood Coating Performance Using Atmospheric Plasma Treatment and Design of Experiments Method

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1520
Author(s):  
Ender Hazir
Keyword(s):  
Heat Treatment ◽  
Plasma Treatment ◽  
Adhesion Strength ◽  
Treatment Process ◽  
Colour Change ◽  
Treated Wood ◽  
Atmospheric Plasma ◽  
Heat Treatment Process ◽  
Coating Performance ◽  
Heat Treated

The aim of this work is to improve the heat-treated wood coating performance using experimental design methodology and air–plasma treatment. Firstly, two different heat treatment processes were applied to the wood samples. In the second stage of the study, air–atmospheric plasma treatment was applied to heat-treated samples. These samples were coated with water-based varnish. Adhesion strength and colour change values of these samples before and after the artificial weathering test were measured. The design of experiments method was used to investigate the significant factors. The heat treatment process (212 °C—1 h and 212 °C—2 h) and atmospheric plasma treatment parameters (pressure, distance, and feed) were selected as independent variables, while adhesion strength and colour change were determined as dependent variables. The factors affecting the surface coating performance before and after the artificial weathering test were evaluated by analysis of variance (ANOVA) and Pareto plot. In addition, the factor levels that maximise the adhesion strength value and minimise the colour change were found using the multiobjective optimisation technique. According to the multiobjective optimisation method, results of treatment feed, working distance, and pressure of 60 mm/s, 7.69 mm, and 1 bar were considered as optimum plasma treatment conditions, respectively, for heat treatment process A. Corresponding values for the heat treatment process B were 60 mm/s, 10 mm, and 2 bar.

scholarly journals Benefits of Nonthermal Atmospheric Plasma Treatment on Dentin Adhesion

2018 ◽  
Vol 43 (6) ◽  
pp. E288-E299 ◽  
Author(s):  
AP Ayres ◽  
PH Freitas ◽  
J De Munck ◽  
A Vananroye ◽  
C Clasen ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Water Storage ◽  
Contact Angles ◽  
The Other ◽  
Atmospheric Plasma ◽  
Hybrid Layer ◽  
Water Contact ◽  
Dentin Surface

SUMMARY Objectives: This study aimed to evaluate the influence of two nonthermal atmospheric plasma (NTAP) application times and two storage times on the microtensile bond strength (μTBS) to dentin. The influence of NTAP on the mechanical properties of the dentin-resin interface was studied by analyzing nanohardness (NH) and Young's modulus (YM). Water contact angles of pretreated dentin and hydroxyapatite blocks were also measured to assess possible alterations in the surface hydrophilicity upon NTAP. Methods and Materials: Forty-eight human molars were used in a split-tooth design (n=8). Midcoronal exposed dentin was flattened by a 600-grit SiC paper. One-half of each dentin surface received phosphoric acid conditioning, while the other half was covered with a metallic barrier and remained unetched. Afterward, NTAP was applied on the entire dentin surface (etched or not) for 10 or 30 seconds. The control groups did not receive NTAP treatment. Scotchbond Universal (SBU; 3M ESPE) and a resin-based composite were applied to dentin following the manufacturer's instructions. After 24 hours of water storage at 37°C, the specimens were sectioned perpendicular to the interface to obtain approximately six specimens or bonded beams (approximately 0.9 mm2 in cross-sectional area) representing the etch-and-rinse (ER) approach and another six specimens representing the self-etch (SE) approach. Half of the μTBS specimens were immediately loaded until failure, while the other half were first stored in deionized water for two years. Three other bonded teeth were selected from each group (n=3) for NH and YM evaluation. Water contact-angle analysis was conducted using a CAM200 (KSV Nima) goniometer. Droplet images of dentin and hydroxyapatite surfaces with or without 10 or 30 seconds of plasma treatment were captured at different water-deposition times (5 to 55 seconds). Results: Two-way analysis of variance revealed significant differences in μTBS of SBU to dentin after two years of water storage in the SE approach, without differences among treatments. After two years of water aging, the ER control and ER NTAP 10-second groups showed lower μTBS means compared with the ER NTAP 30-second treated group. Nonthermal atmospheric plasma resulted in higher NH and YM for the hybrid layer. The influence of plasma treatment in hydrophilicity was more evident in the hydroxyapatite samples. Dentin hydrophilicity increased slightly after 10 seconds of NTAP, but the difference was higher when the plasma was used for 30 seconds. Conclusions: Dentin NTAP treatment for 30 seconds contributed to higher μTBS after two years of water storage in the ER approach, while no difference was observed among treatments in the SE evaluation. This result might be correlated to the increase in nanohardness and Young's modulus of the hybrid layer and to better adhesive infiltration, since dentin hydrophilicity was also improved. Although some effects were observed using NTAP for 10 seconds, the results suggest that 30 seconds is the most indicated treatment time.

scholarly journals The Effect of Atmospheric Plasma on the Solubility and Dispersibility of Powdered Whey Protein Isolate

2018 ◽  
Author(s):  
Heidi Lightfoot
Keyword(s):  
Plasma Treatment ◽  
Whey Protein ◽  
Functional Properties ◽  
Protein Solubility ◽  
Whey Protein Isolate ◽  
Protein Isolate ◽  
Atmospheric Plasma ◽  
Pristine Sample ◽  
Food And Nutrition ◽  
The Impact

Functional properties of protein macromolecules such as protein solubility are of particular interest to the food and nutrition industries as they have significant implications on other useful properties and characteristics for the development of nutritional and food supplements. Consequently, proteins with specific and consistent functional characteristics are in high demand as essential ingredients in formulated food or in pharmaceutical and industrial mixtures. Proteins need to be highly soluble so that their functional properties can be effectively exploited, therefore methods to improve the solubility of protein powders are currently being developed. It has been hypothesized that atmospheric plasma treatment has an effect on protein solubility and dispersibility. This theory has not been yet explored with whey protein isolate elsewhere; this study is the first to explore the impact of plasma based treatment. The effect of atmospheric plasma treatment on the solubility and dispersibility of dry protein powder has been studied. Each variable was examined using both a pristine sample of whey protein isolate and a sample of whey protein isolate from the same product batch that had been exposed to atmospheric plasma (following ISO 8156 and ISO/TS 17758 protocols). We demonstrate that plasma can successfully increase the solubility and dispersibility of whey protein powder.

scholarly journals Degradation of thermo-hygro-mechanically (THM)-densified wood by soft-rot fungi

Holzforschung ◽  
2008 ◽  
Vol 62 (3) ◽  
Author(s):  
Oleksandr Skyba ◽  
Peter Niemz ◽  
Francis W.M.R. Schwarze
Keyword(s):  
Lignin Content ◽  
Beech Wood ◽  
Treated Wood ◽  
Untreated Wood ◽  
Soft Rot ◽  
Saturated Steam ◽  
Densified Wood ◽  
Microscopical Examination ◽  
Weight Losses ◽  
Spruce Wood

Abstract Thermo-hygro-mechanical (THM)-densified wood is more resistant to colonisation and degradation by brown-rot fungi than untreated wood. Colonisation and degradation by soft-rot fungi was investigated in treated Norway spruce (Picea abies) and treated beech (Fagus sylvatica) to assess their suitability for utility class 4. Three different treatments were applied: thermal-hygro (TH) treatment, mechanical densification and THM-treatment including densification and post-treatment under saturated steam conditions at different temperatures. For comparison, additional wood specimens were treated with two concentrations of a chromium-copper (CC) wood preservative. After 32 weeks incubation, weight losses induced by soft-rot fungi were lowest in wood treated with CC. Highest weight losses were recorded from TH-treated wood, in which soft-rot erosion attack (type 2) was exclusively observed in spruce. In comparison to controls, significantly lower weight losses by soft-rot fungi were recorded in THM-treated spruce wood, but no such differences were found in beech wood. Microscopical examination showed that in THM-treated wood of spruce, soft-rot type 1 commenced from the outer wood surfaces and cavity formation was not found in deeper regions of the wood samples. THM-treated beech wood was more susceptible to degradation than that of spruce which can be partly explained by the higher syringyl lignin content in beech wood, which is more susceptible to all kinds of degradation. Hyphal colonisation and soft-rot was facilitated within deeper regions of beech wood mainly in the non-occluded lumina of parenchyma cells in multiseriate xylem rays. It can be concluded that TH-treated spruce wood and THM-treated beech wood is susceptible to soft-rot and therefore inappropriate for utility class 4.

Bonding Performance of Wood Treatment by Oxygen and Nitrogen Cold Plasma

2014 ◽  
Vol 633-634 ◽  
pp. 583-588 ◽  
Author(s):  
Hong Yan Wang ◽  
Guan Ben Du ◽  
Qin Li ◽  
Rui Ying Xu ◽  
Shao Fei Yuan
Keyword(s):  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
Cold Plasma ◽  
Treated Wood ◽  
Untreated Wood ◽  
Atomic Ratio ◽  
Contact Angles ◽  
X Ray ◽  
Bonding Performance ◽  
Processing Power

The wood were treated by N2,O2cold plasma with the processing power 300W, the treatment duration 5 min, then the treated wood was bonded with MUF to valve the bonding performance, the contact angles of the treated/untreated wood were tested. The chemical composition on the surface of wood with or without N2cold plasma treatment also was analyzed by X-ray photoelectron spectroscopy (XPS). The results showed: the contact angles of the surface decreased, the surface free energy increased evidently that treated by N2or O2cold plasma, and the average bonding performance of wood that treated by cold plasma (whether N2or O2) increased obviously, more than 50% comparing with that untreated. The XPS analysis showed the atomic ratio O/C has increased, and more groups were oxidized or more peroxides were formed on the surface of wood, and the N element was introduced to the wood surface after nitrogen cold plasma treatment and it was guessed to the group of –NH2.

scholarly journals Correction to: Enhancement of strength of adhesive bond between wood and metal using atmospheric plasma treatment

Cellulose ◽  
2021 ◽  
Vol 28 (5) ◽  
pp. 3295-3295
Author(s):  
Jure Žigon ◽  
Janez Kovač ◽  
Rok Zaplotnik ◽  
Jaša Saražin ◽  
Milan Šernek ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Adhesive Bond ◽  
Atmospheric Plasma

Cold atmospheric plasma treatment for diaper dermatitis: A case report

2021 ◽  
Author(s):  
Chenchen Zhang ◽  
Jun Zhao ◽  
Yamei Gao ◽  
Jing Gao ◽  
Yongmei Lv
Keyword(s):  
Case Report ◽  
Plasma Treatment ◽  
Atmospheric Plasma ◽  
Diaper Dermatitis ◽  
Cold Atmospheric Plasma

scholarly journals Plasma Treatment of Fish Cells: The Importance of Defining Cell Culture Conditions in Comparative Studies

2021 ◽  
Vol 11 (6) ◽  
pp. 2534
Author(s):  
Henrike Rebl ◽  
Claudia Bergemann ◽  
Sebastian Rakers ◽  
Barbara Nebe ◽  
Alexander Rebl
Keyword(s):  
Plasma Treatment ◽  
Cell Lines ◽  
Mammalian Cells ◽  
Atmospheric Pressure Plasma ◽  
Fish Farming ◽  
Skin Lesions ◽  
Atmospheric Plasma ◽  
Fish Cell ◽  
Farmed Fish ◽  
Fish Cells

The present study provides the fundamental results for the treatment of marine organisms with cold atmospheric pressure plasma. In farmed fish, skin lesions may occur as a result of intensive fish farming. Cold atmospheric plasma offers promising medical potential in wound healing processes. Since the underlying plasma-mediated mechanisms at the physical and cellular level are yet to be fully understood, we investigated the sensitivity of three fish cell lines to plasma treatment in comparison with mammalian cells. We varied (I) cell density, (II) culture medium, and (III) pyruvate concentration in the medium as experimental parameters. Depending on the experimental setup, the plasma treatment affected the viability of the different cell lines to varying degrees. We conclude that it is mandatory to use similar cell densities and an identical medium, or at least a medium with identical antioxidant capacity, when studying plasma effects on different cell lines. Altogether, fish cells showed a higher sensitivity towards plasma treatment than mammalian cells in most of our setups. These results should increase the understanding of the future treatment of fish.

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

Sign in / Sign up

Export Citation Format

Share Document