Functionalized Surface Layer on Poplar Wood Fabricated by Fire Retardant and Thermal Densification. Part 2: Dynamic Wettability and Bonding Strength

In continuation of our former study on a novel combined treatment of nitrogen–phosphorus fire retardant and thermomechanical densification on wood, this study focuses on the dynamic wettability and the bonding strength. The contact angle was measured using the sessile drop method and the surface energy was calculated according to the van Oss method. Water surface penetrating and spreading is analyzed by both the Shi and Gardner model and the droplet volume changing model. The results reveal that the combined treatment increased the surface energy, especially the acid–base component. The contact angle declined and the water droplet spread more easily on the surface. Meanwhile, the rate of relative droplet volume decreased by 32.6% because the surface layer was densified and stabilized by the combined process. Additionally, the surface possesses the lowest roughness and highest abrasion resistance on the tangential section. Thus, the bonding strength of the combined treated poplar decreased by 29.7% compared to that of untreated poplar; however, it is still 53.3% higher than that of 220 °C heat-treated wood.

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Functionalized Surface Layer on Poplar Wood Fabricated by Fire Retardant and Thermal Densification. Part 1: Compression Recovery and Flammability

Forests ◽

10.3390/f10110955 ◽

2019 ◽

Vol 10 (11) ◽

pp. 955 ◽

Cited By ~ 4

Author(s):

Demiao Chu ◽

Jun Mu ◽

Stavros Avramidis ◽

Sohrab Rahimi ◽

Shengquan Liu ◽

...

Keyword(s):

Surface Layer ◽

Combined Treatment ◽

Surface Hardness ◽

Treated Wood ◽

Fire Retardant ◽

Densified Wood ◽

Fire Retardancy ◽

Alternative Approach ◽

Vertical Density ◽

Functionalized Surface

To enhance compression stability and fire retardancy of densified wood, a new modification method i.e., combined nitrogen–phosphorus (NP) fire retardant pre-impregnation with surface thermo-mechanical densification is used to fabricate a certain thickness of functionalized surface layer on poplar. This combined treated wood is investigated via vertical density profile (VDP), and the compression stability is revealed by both soaking test and cone analysis. Results demonstrate that the combined treatment hardened the surface of wood and reformed the interface combination of the NP with the wood cell wall, thus making the surface tissue more close-grained. Fire retardancy was also enhanced; the total heat release and CO generation values decreased by 21.9% and 68.4%, respectively, when compared with that of solely NP-treated wood. Moreover, surface hardness increased by 15.8%, and the recovery of surface hardness and thickness were 56.8% and 77.2% lower than that of simply densified wood. It appears that this NP-involved thermal densification could be considered as an alternative approach to enhance both the compression stability and fire resistance of wood.

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Effect of heat treatment on bonding performance of poplar via an insight into dynamic wettability and surface strength transition from outer to inner layers

Holzforschung ◽

10.1515/hf-2019-0145 ◽

2020 ◽

Vol 74 (8) ◽

pp. 777-787 ◽

Cited By ~ 1

Author(s):

Demiao Chu ◽

Jun Mu ◽

Stavros Avramidis ◽

Sohrab Rahimi ◽

Zongyuan Lai ◽

...

Keyword(s):

Heat Treatment ◽

Surface Layer ◽

Outer Surface ◽

Near Infrared ◽

Sessile Drop ◽

Treated Wood ◽

Tangential Section ◽

Surface Strength ◽

Heat Treated ◽

Bonding Failure

AbstractHeat treatment (HT) is thought to degrade wood surface wettability and cause gluing problems; this study focused on wettability and surface strength of the surface layer on heat-treated wood. The outer and inner surfaces formed by removing the 1-, 2- and 3-mm surface layers of heat-treated poplar on the tangential section were investigated. Dynamic wetting was analyzed according to the sessile drop method. The bonding failure models on different surfaces were also discussed based on both images of macro- and microscopic fracture interfaces. Using Fourier-transform near-infrared spectroscopy (FT-NIR), the cell wall chemistry on both outer and inner surfaces were analyzed. The results showed that the bonding strength of the outer surface was mainly affected by wettability, whereas the surface strength became the key factor for the inner layers. The removal of the first 1 mm of the surface layer enhanced the wetting process and transferred the failure mode from the glue line to the wood itself. FT-NIR revealed that the intensity of the thermal degradation on inner layers was alleviated with the removal depth; wettability and surface strength were enhanced compared with the outer surface. Surface abrasion and hardness declined, decreasing the surface strength and bonding capacity. This study indicates that the bonding of heat-treated wood is truly affected by the surface strength of the inner layers, in addition to the wettability on the outer surface.

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Comparative Study of Surface Energies of Native Oxides of Si(100) and Si(111) via Three Liquid Contact Angle Analysis

MRS Advances ◽

10.1557/adv.2018.473 ◽

2018 ◽

Vol 3 (57-58) ◽

pp. 3379-3390 ◽

Cited By ~ 5

Author(s):

Saaketh R. Narayan ◽

Jack M. Day ◽

Harshini L. Thinakaran ◽

Nicole Herbots ◽

Michelle E. Bertram ◽

...

Keyword(s):

Contact Angle ◽

Surface Energy ◽

Sessile Drop ◽

Surface Composition ◽

Ion Beam ◽

Contact Angles ◽

Van Der Waals Interactions ◽

Native Oxides ◽

Relative Errors ◽

Contact Angle Analysis

ABSTRACTThe effects of crystal orientation and doping on the surface energy, γT, of native oxides of Si(100) and Si(111) are measured via Three Liquid Contact Angle Analysis (3LCAA) to extract γT, while Ion Beam Analysis (IBA) is used to detect Oxygen. During 3LCAA, contact angles for three liquids are measured with photographs via the “Drop and Reflection Operative Program (DROP™). DROP™ removes subjectivity in image analysis, and yields reproducible contact angles within < ±1°. Unlike to the Sessile Drop Method, DROP can yield relative errors < 3% on sets of 20-30 drops. Native oxides on 5 x 1013 B/cm3 p- doped Si(100) wafers, as received in sealed, 25 wafer teflon boats continuously stored in Class 100/ISO 5 conditions at 24.5°C in 25% controlled humidity, are found to be hydrophilic. Their γT, 52.5 ± 1.5 mJ/m2, is reproducible between four boats from three sources, and 9% greater than γT of native oxides on n- doped Si(111), which averages 48.1 ± 1.6 mJ/m2 on four 4” Si(111) wafers. IBA combining 16O nuclear resonance with channeling detects 30% more oxygen on native oxides of Si(111) than Si(100). While γT should increase on thinner, more defective oxides, Lifshitz-Van der Waals interactions γLW on native oxides of Si(100) remain at 36 ± 0.4 mJ/m2, equal to γLW on Si(111), 36 ± 0.6 mJ/m2, since γLW arises from the same SiO2 molecules. Native oxides on 4.5 x 1018 B/cm3 p+ doped Si(100) yield a γT of 39 ± 1 mJ/m2, as they are thicker per IBA. In summary, 3LCAA and IBA can detect reproducibly and accurately, within a few %, changes in the surface energy of native oxides due to thickness and surface composition arising from doping or crystal structure, if conducted in well controlled clean room conditions for measurements and storage.

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Combustion behavior of oak wood (Quercus mongolica L.) modified by 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU)

Holzforschung ◽

10.1515/hf-2013-0224 ◽

2014 ◽

Vol 68 (8) ◽

pp. 881-887 ◽

Cited By ~ 11

Author(s):

Yanjun Xie ◽

Na Liu ◽

Qingwen Wang ◽

Zefang Xiao ◽

Fengqiang Wang ◽

...

Keyword(s):

Combined Treatment ◽

Treated Wood ◽

Fire Retardant ◽

Untreated Wood ◽

Cone Calorimetry ◽

Oak Wood ◽

Quercus Mongolica ◽

Combustion Behavior ◽

Service Period ◽

Public Areas

Abstract The modification of wood with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) is an efficient strategy to improve its dimensional stability and durability during its service period. In this study, oak wood (Quercus mongolica L.) was treated with DMDHEU and the combustion behavior of the treated wood was examined. The bench-scale thermogravimetry and cone calorimetry showed that the treatment with DMDHEU alone enhanced the flammability of wood, but a combined treatment with DMDHEU and traces of magnesium chloride as a catalyst lowered the flammability to the level of untreated wood. In full-scale fire tests for flooring materials, it could be confirmed that both the untreated and treated woods have similar combustion behavior and can be classified as Dfl-S1 (capable of resisting a small flame and, for a certain period, a heat flux attack; the total smoke production is limited). Accordingly, further fire-retardant treatments may be required if DMDHEU-treated wood is used in public areas.

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Promotion effect of NP fire retardant pre-treatment on heat-treated poplar wood. Part 2: hygroscopicity, leaching resistance, and thermal stability

Holzforschung ◽

10.1515/hf-2016-0213 ◽

2017 ◽

Vol 71 (3) ◽

pp. 217-223 ◽

Cited By ~ 9

Author(s):

Demiao Chu ◽

Jun Mu ◽

Li Zhang ◽

Yushuang Li

Keyword(s):

Thermal Stability ◽

Moisture Absorption ◽

Degradation Products ◽

Combined Treatment ◽

Treated Wood ◽

Fire Retardant ◽

Crystallinity Index ◽

Hydroxyl Groups ◽

Heat Treated ◽

Wood Polysaccharides

Abstract In continuation of the previous study concerning the effects of a combined treatment of wood with nitrogen-phosphorus (NP) fire retardant and heat treatment (HT), the hygroscopicity, leachability, thermal stability, Fourier transform-infrared (FT-IR) spectra, and X-ray diffraction (XRD) properties of Populus beijingensis W.Y. Hsu have been investigated. The wood samples were impregnated with 10% NP fire retardant solution and exposed to HTs at 140°C–160°C for 30 min. HT of NP treated wood reduced the moisture absorption and enhanced the leaching resistance of NP and improved the thermal stability. The HT decomposes the NP and the acidity of these degradation products has a dehydration effect on the wood polysaccharides, and the number of hydroxyl groups in wood decreased substantially. The crystallinity index of the NP-impregnated and heat-treated wood also increased. The post low-temperature HT enhanced the fixation of the NP fire retardant and hydrophobicity of the NP-treated wood.

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Synthesis, Characterization and Wettability of Cu-Sn Alloy on the Si-Implanted 6H-SiC

Coatings ◽

10.3390/coatings10090906 ◽

2020 ◽

Vol 10 (9) ◽

pp. 906 ◽

Cited By ~ 2

Author(s):

Xiang Zhao Zhang ◽

Pu Hao Xu ◽

Gui Wu Liu ◽

Awais Ahmad ◽

Xiao Hui Chen ◽

...

Keyword(s):

Contact Angle ◽

Surface Energy ◽

Sessile Drop ◽

Contact Angles ◽

Graphite Layer ◽

Sessile Drop Technique ◽

Sic Ceramics ◽

Sic Ceramic ◽

Interfacial Chemical Reaction ◽

Drop Technique

The wettability of the metal/SiC system is not always excellent, resulting in the limitation of the widespread use of SiC ceramic. In this paper, three implantation doses of Si ions (5 × 1015, 1 × 1016, 5 × 1016 ions/cm2) were implanted into the 6H-SiC substrate. The wetting of Cu-(2.5, 5, 7.5, 10) Sn alloys on the pristine and Si-SiC were studied by the sessile drop technique, and the interfacial chemical reaction of Cu-Sn/SiC wetting couples was investigated and discussed. The Si ion can markedly enhance the wetting of Cu-Sn on 6H-SiC substrate, and those of the corresponding contact angles (θ) are raised partly, with the Si ion dose increasing due to the weakening interfacial chemical reactions among four Cu-Sn alloys and 6H-SiC ceramics. Moreover, the θ of Cu-Sn on (Si-)SiC substrate is first decreased and then increased from ~62° to ~39°, and ~70° and ~140°, with the Sn concentration increasing from 2.5%, 5% and 7.5% to 10%, which is linked to the reactivity of Cu-Sn alloys and SiC ceramic and the variation of liquid-vapor surface energy. Particularly, only a continuous graphite layer is formed at the interface of the Cu-10Sn/Si-SiC system, resulting in a higher contact angle (>40°).

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172 nm Excimer Radiation as a Technology Accelerator for Bio-Electronic Applications

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.255.366 ◽

2016 ◽

Vol 255 ◽

pp. 366-372

Author(s):

Andreas Schäfert ◽

Hartwig Wiesmann

Keyword(s):

Contact Angle ◽

Surface Energy ◽

Electric Fields ◽

Mass Spectroscopy ◽

Bonding Strength ◽

Negative Charge ◽

Surface Activation ◽

Static Electricity ◽

Material Combination ◽

Applied Dose

The publication reviews recent applications of 172nm excimer radiation in bio-electric fields. It shows the broad field which already profit from the technology and also illustrates possible potentials. The principle of erasing static electricity from polyimide surfaces is explained as one application. The effect as a function of the dose is presented both for positive and negative charge and typical materials.In addition the VUV cleaning mechanism with 172nm excimer radiation is demonstrated by the mass spectroscopy of contaminations on the surface of a Si wafer.Surface energy changes of polyamides, glass and metal as a function of dose are presented as well as the change of the contact angle of water on the surface.Another application of surface energy enhancement is the polymer microchip production. Due to the surface activation, the bonding strength for the PMMA-Si combination is significantly enhanced. The results are presented in comparison to other surface treatment methods.Another presented application which profits from the surface activation is adhesive-free coupling. The mechanism of this application is explained and the adhesion strength as a function of material combination is presented. For 2 typical applications, the bonding strength is shown as a function of applied dose. A glance at other applications and an outlook is given as well.

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Wettability and Treatability of Sengon (Paraserianthes falcataria (L.) I.C. Nielsen) wood from NTB

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/891/1/012015 ◽

2021 ◽

Vol 891 (1) ◽

pp. 012015

Author(s):

A T Lestari ◽

E Wahyuningsih ◽

M Syaputra ◽

H Anwar ◽

P K Suparyana ◽

...

Keyword(s):

Contact Angle ◽

Sessile Drop ◽

Sample Surface ◽

Wood Preservation ◽

Equilibrium Contact Angle ◽

Tangential Section ◽

Natural Forests ◽

Paraserianthes Falcataria ◽

Fast Growing ◽

Durability Testing

Abstract The supply of wood from natural forests is decreasing as a result of the imbalance between harvesting and planting. The lack of wood supply from natural forests has resulted in relatively expensive wood prices. This can be anticipated by using fast-growing wood species. One type of fast-growing wood which is very abundantly available in NTB is sengon wood (Paraserianthes falcataria (L.) I.C. Nielsen). However, sengon wood has low durability so it is easily attacked by wood-destroying organisms. This condition can be overcome by making efforts to prevent wood damage in the form of preservation. This study aims to determine the wettability and treatability properties of sengon wood. The results of this study are expected to be basic information to improve the quality of sengon wood. The wettability test was carried out by measuring the contact angle between the liquid and the sample surface using the sessile drop method and the wood durability testing was carried out by measuring the retention and penetration of preservatives. The treatability test was carried out by measuring the absorption, retention, and penetration of preservatives. The results showed that the wettability of sengon is high with an equilibrium contact angle (θe) of 16.88 in the radial section and 12.51 in the tangential section. This shows that sengon wood has a good adhesion system for preservation. Treatability of sengon wood showed that the average retention and penetration are 10,21 kg/m3 and 7,33 mm. Based on the results of these measurements, sengon wood has met SNI 03-5010.1-1999 (wood preservation for housing and buildings).

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The diamond-solution interface: the surface energy of hydrogen terminated nanocrystalline CVD diamond derived from contact angle measurements

MRS Proceedings ◽

10.1557/opl.2011.1019 ◽

2011 ◽

Vol 1362 ◽

Author(s):

Stoffe D. Janssens ◽

Sien Drijkoningen ◽

Marc Saitner ◽

Hans-Gerd Boyen ◽

Ken Haenen ◽

...

Keyword(s):

Contact Angle ◽

Surface Energy ◽

Photoelectron Spectroscopy ◽

Microwave Plasma ◽

Sessile Drop ◽

Chemical Vapor ◽

Nanocrystalline Diamond ◽

Silicon Substrates ◽

Angle Measurements ◽

Contact Angle Measurements

ABSTRACTIn this work, a determination of the surface energy for hydrogen terminated nanocrystalline diamond grown with microwave plasma enhanced chemical vapor deposition is presented. Five identical hydrogen terminated nanocrystalline diamond layers of ~150 nm thick are deposited on silicon substrates and examined with X-ray photoelectron spectroscopy to determine the surface groups and possible surface contaminations. In order to evaluate the surface energy, contact angle measurements are performed using the sessile drop method in combination with data analysis based on the ‘Owens, Wendt, Rabel and Kaelble’ method. Four different experimental approaches to evaluate the surface energy of hydrogen terminated nanocrystalline diamond are discussed.

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Surface Testing of Dental Biomaterials—Determination of Contact Angle and Surface Free Energy

Materials ◽

10.3390/ma14112716 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2716

Author(s):

Aneta Liber-Kneć ◽

Sylwia Łagan

Keyword(s):

Contact Angle ◽

Free Energy ◽

Surface Energy ◽

Surface Free Energy ◽

Sessile Drop ◽

Dental Materials ◽

Free Energy Calculations ◽

Critical Surface ◽

Free Energies ◽

Acrylic Resins

The key goal of this study was to characterize surface properties of chosen dental materials on the base on the contact angle measurements and surface free energy calculations. Tested materials were incubated in the simulated oral environment and drinks to estimate an influence of conditions similar to those in the oral cavity on wetting and energetic state of the surface. Types of materials were as follows: denture acrylic resins, composite and PET-G dental retainer to compare basic materials used in a prosthetics, restorative dentistry and orthodontics. The sessile drop method was used to measure the contact angle with the use of several liquids. Values of the surface free energies were estimated based on the Owens–Wendt, van Oss–Chaudhury–Good and Zisman’s methods. The research showed that surface wetting depends on the material composition and storage conditions. The most significance changes of CA were observed for acrylic resins (84.7° ± 3.8° to 65.5° ± 3.5°) and composites (58.8° ± 4.1° to 49.1° ± 5.7°) stored in orange juice, and for retainers (81.9° ± 1.8° to 99.6° ± 4.5°) incubated in the saline solution. An analysis of the critical surface energy showed that acrylic materials are in the zone of good adhesion (values above 40 mJ/m2), while BIS-GMA composites are in the zone of poor adhesion (values below 30 mJ/m2). Study of the surface energy of different dental materials may contribute to the development of the thermodynamic model of bacterial adhesion, based on the surface free energies, and accelerate the investigation of biomaterial interaction in the biological environment.

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