scholarly journals Influence of Citric Acid on the Bond Strength of Beech Wood

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2801
Author(s):  
Goran Mihulja ◽  
Vjekoslav Živković ◽  
Dominik Poljak ◽  
Bogoslav Šefc ◽  
Tomislav Sedlar
Keyword(s):  
Citric Acid ◽  
Surface Energy ◽  
Bond Strength ◽  
Beech Wood ◽  
Solid Wood ◽  
Adhesive Properties ◽  
Minimum Requirements ◽  
Fagus Silvatica ◽  
Unmodified Wood ◽  
Modified Wood

In this study, beech wood (Fagus silvatica L.) has been chemically modified with citric acid (Acidum citricum) and sodium hypophosphate (SHP) as the catalyst and gradually thermo-condensed in the dryer. Afterwards, wetting angle, surface energy, and shear strength of glued joints of modified and unmodified wood were determined. Testing of the bond strength according to standard EN 204 and comparison between modified and unmodified samples were executed. The adhesive used for bonding samples was polyvinyl acetate (PVAC), commonly used for gluing solid wood panels. Testing material was divided into three groups (dry, wet, and wet conditioned samples), within which statistical analysis was performed, and the significance of the differences between the modified and unmodified samples was determined. Surface energy is correlated with the bond strength, indicating that modification with citric acid negatively affects the adhesive properties of beech wood. A reduction in the bond strength of modified wood glued with PVAC glue compared to unmodified wood was determined. All the results indicate that the modified samples do not meet the minimum requirements for EN 204 bonded with PVAC glue. Therefore, it will be necessary to conduct further studies using other types of adhesives to investigate whether modified wood might be suitable for gluing.

Physical and Adhesive Properties of Cyanoacrylate-Based β-TCP Composites

2007 ◽  
Vol 330-332 ◽  
pp. 419-422 ◽  
Author(s):  
G.S. Lee ◽  
Sang Bae Lee ◽  
Doug Youn Lee ◽  
Kyeong Jun Park ◽  
S.O. Kim ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Citric Acid ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Setting Time ◽  
Tissue Adhesive ◽  
Adhesive Properties ◽  
Composite Systems ◽  
Filling Materials

Histoacryl® (N-butyl-2-cyanoacrylate) has been widely utilized as a tissue adhesive. The aim of this study was to evaluate the physical and adhesive properties of newly developed cyanoacrylate-based β-TCP composite systems. The β-TCP powder was modified on the surface with citric acid to make this material mixed with cyanoacrylate easily. The setting time of acidtreated β-TCP/ Histoacryl® systems was dramatically prolonged and the polymerization heat was significantly decreased compared to that of untreated β-TCP/Histoacryl® system. The shear bond strength of cyanoacrylate-based β-TCP composites decreased with addition of acid-treated β-TCP filler. The compressive strength of β-TCP/Histoacryl® composites increased strongly with increasing the amount of acid-treated β-TCP filler. The cytotoxicity of the β-TCP/Histoacryl® composites decreased with the increasing of the amount of added β-TCP. These results indicated that our novel β-TCP/Histoacryl® composites had the great potential to serve as adhesives or filling materials in the dental field.

Colour stability of surface finishes on thermally modified beech wood

2021 ◽  
Vol 114 ◽  
pp. 116-124
Author(s):  
Gabriela Slabejová ◽  
MÁRIA ŠMIDRIAKOVÁ
Keyword(s):  
Surface Finish ◽  
Beech Wood ◽  
Surface Finishing ◽  
Colour Stability ◽  
Colour Difference ◽  
Surface Finishes ◽  
Before And After ◽  
Thermally Modified Wood ◽  
Wood Surfaces ◽  
Modified Wood

Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ∆E* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.

scholarly journals Sifat Papan Partikel Bambu Petung (Dendrocalamus asper) dan Bambu Wulung (Gigantochloa atroviolacea) dengan Perlakuan Ekstraksi

2020 ◽  
Vol 14 (1) ◽  
pp. 84
Author(s):  
Ragil Widyorini ◽  
Ikhwan Syahri ◽  
Greitta Kusuma Dewi
Keyword(s):  
Citric Acid ◽  
Bond Strength ◽  
Internal Bond ◽  
Cold Water ◽  
Internal Bond Strength ◽  
Modulus Of Rupture ◽  
Bamboo Species ◽  
Japanese Industrial Standard ◽  
Dendrocalamus Asper ◽  
Extraction Treatment

Bambu memiliki kandungan ekstraktif dengan persentase yang berbeda antar jenis bambu. Penelitian ini bertujuan untuk mengetahui pengaruh perlakuan ekstraksi pada jenis bambu yang berbeda terhadap sifat papan partikel. Dua jenis bambu digunakan yaitu Bambu Petung (Dendrocalamus asper) dan Bambu Wulung (Gigantochloa atroviolacea). Perlakuan ekstraksi digunakan pada partikel bambu sebelum proses pembuatan papan partikel yaitu tanpa ekstraksi, ekstraksi air dingin dan ekstraksi air panas. Papan partikel dibuat dalam ukuran 25 cm x 25 cm x 0,7 cm, target kerapatan 0,9 g/cm3, jumlah asam sitrat 30%, serta kondisi pengempaan suhu 180°C selama 10 menit. Hasil penelitian menunjukkan bahwa interaksi perlakuan ekstraksi dan jenis bambu hanya berpengaruh signifikan pada sifat penyerapan air dan keteguhan rekat internal, sedangkan jenis bambu berpengaruh signifikan pada nilai kadar air, modulus patah dan modulus elastisitas. Semua papan partikel yang dihasilkan memenuhi standar Japanese Industrial Standard (JIS) A 5908 tipe 13. Pada penelitian ini, papan partikel dari bambu wulung tanpa perlakuan ekstraksi mempunyai nilai yang memenuhi standar tipe 18 dan berpotensi sebagai bahan baku untuk produk furnitur eksterior. Perlakuan ekstraksi dapat meningkatkan secara signifikan nilai keteguhan rekat internal papan partikel bambu petung, walaupun secara umum dengan jumlah asam sitrat 30% perlakuan tersebut tidak diperlukan pada papan partikel bambu Properties of Particleboard made from Petung Bamboo (Dendrocalamus asper) and Wulung Bamboo (Gigantochloa atroviolacea) Particles with Extraction TreatmentAbstractBamboo has extractives, which the percentage of extractive was different based on bamboo species. This research aimed to investigate the effect of extraction treatment at different bamboo species on the particleboard properties. Two types of bamboo were used, i.e. Petung bamboo (Dendrocalamus asper) and Wulung bamboo (Gigantochloa atroviolacea). Three extraction treatments were conducted to the bamboo particles before the particleboard manufacture, i.e. unextracted, cold-water extraction, and hot-waterextraction. The particleboard was made in the size of 25 cm x 25 cm x 0.7 cm, target density of 0.9 g/cm³, citric acid content of 30%, and pressing temperature of 180°C for 10 min. The results showed that the interaction between extraction treatment and bamboo species significantly affected on the water absorption and internal bond strength, however bamboo species affected significantly on the moisture content, modulus of rupture, and modulus of elasticity. All of particleboards could met the requirement of the 13 type of Japanese Industrial Standard (JIS) A 5908. In this research, particleboards made from wulung bamboo particles without extraction treatment have properties that met the requirement of the 18 type and the products have potential to be as exterior materials for furniture. In general, an extraction treatment was not an important step on the manufacturing of bamboo particleboard using citric acid 30% as adhesive. However, the extraction treatment could increase significantly the internal bond strength of particleboard made from petung bamboo.

scholarly journals Properties of Pinus modified with silicon–titanium binary oxides

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 747-763
Author(s):  
Xiaoling Liu ◽  
Songwu Chen ◽  
Yunlin Fu
Keyword(s):  
Wood Surface ◽  
Color Change ◽  
Sol Gel ◽  
Resistance Testing ◽  
Chemical Bonds ◽  
Noticeable Increase ◽  
Aging Resistance ◽  
Tio2 Gel ◽  
Unmodified Wood ◽  
Modified Wood

Modification of Pinus yunnanensis using SiO2–TiO2 was carried out via the sol–gel method. The aim was to improve the hydrophobicity, aging resistance, and photocatalysis of the wood surface via the formation of new chemical bonds with penetrated SiO2 and TiO2. The air-dried P. yunnanensis wood underwent penetration, gelation, aging, and drying. The wood was exposed to high temperatures for modification, and its microstructure, composition, photodegradability, resistance to aging, dimensional stability, and hydrophobicity were then determined. The results indicated that during modification, SiO2–TiO2 gel was generated in the wood, and the content of the gel increased as penetration time was extended. No structural change in the wood was observed. Meanwhile, chemical bonds were formed among SiO2, TiO2, and wood. The contact angle of the modified wood increased noticeably relative to that of unmodified wood. This increase indicated a noticeable increase in the hydrophobicity of the wood surface. The modified wood exhibited high photocatalytic degradation; however, its durability was not evident. The water absorption and thickness swelling of the modified wood markedly increased. After ultraviolet-aging resistance testing, the color change in the surface of the modified wood was noticeably less than that of the unmodified wood.

scholarly journals Reinforcement of bond strength of self-etching orthodontic adhesive

2011 ◽  
Vol 82 (1) ◽  
pp. 30-35
Author(s):  
Shinya Horiuchi ◽  
Shingo Kuroda ◽  
Masahiro Hiasa ◽  
Toshiyuki Suge ◽  
Seitaro Saku ◽  
...  
Keyword(s):  
Citric Acid ◽  
Phosphoric Acid ◽  
Bond Strength ◽  
Polyacrylic Acid ◽  
Shear Bond Strength ◽  
Adhesive System ◽  
Control Group ◽  
Bonding System ◽  
Adhesive Remnant Index ◽  
Debonding Process

Abstract Objective: To determine the reinforcement of bond strength of a self-etching system by applying a pretreatment agent. Materials and Methods: Sixty extracted human premolars were used in this study. The enamel surfaces were treated with four pretreatment agents—phosphoric acid, polyacrylic acid, citric acid, and ammonium hexafluorosilicate (SiF)—and were examined under a scanning electron microscope. Afterward, orthodontic brackets were bonded with a self-etching adhesive system (n  =  10 for each agent), and shear bond strength was measured through a debonding process. The adhesive remnant index (ARI) was also assessed. Results: Enamel surfaces treated with polyacrylic acid seemed almost the same as intact enamel. Treatment with SiF induced slight shallow depressions compared with the intact enamel. On the other hand, enamel surfaces treated with citric acid and phosphoric acid showed severe etching patterns. All pretreatments increased the bond strength, but SiF-treated specimens revealed the greatest strength (12.201 ± 1.048 MPa), followed by polyacrylic acid (12.030 ± 2.103 MPa). The control group with no pretreatment showed the least strength (9.078 ± 1.678 MPa). All pretreatments increased ARI score compared with the control group. Conclusions: Surface conditioning before bracket adhesion could reinforce the bond strength of the self-etching adhesive system, resulting in a more reliable bonding system.

Fracture Behavior and Tensile Adhesive Properties of HA Coatings

1997 ◽  
Author(s):  
K.A. Khor ◽  
P. Cheang
Keyword(s):  
Bond Strength ◽  
Fracture Behavior ◽  
Size Range ◽  
Deposition Process ◽  
Adhesive Properties ◽  
Particle Size Range ◽  
Powder Morphology ◽  
Bioactive Properties ◽  
Accurate Comparison ◽  
Plasma Sprayed

Abstract The attractive bioactive properties of HA are significantly reduced upon plasma spraying because of the phase transformation that accompanied the deposition process. One major factor that influence the extent to which the transformation occur appears to be the morphology and physical states of the HA raw powders. This paper reports the study on the influence of powder morphology and property on the fracture behaviour and tensile adhesive strength of plasma sprayed HA coatings. Three types of powders were used in the study; calcined HA (CHA), spray dried HA (SDHA) and flame spheroidised HA (SHA). The particle size range of 53 - 75 μm was employed for all 3 types of powders to effect an accurate comparison of the powders. Results show that the cohesive bond strength of the SHA coating was the highest because of the denser microstructure created by well-formed lamella splats. A correspondingly lower bond strength was recorded with less coherent coatings generated by agglomerated CHA and SDHA powders.

Surface Energy of Selected Polyolefins after Radiation Cross-Linking

2015 ◽  
Vol 752-753 ◽  
pp. 342-345
Author(s):  
Martin Bednarik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Jan Navratil ◽  
...  
Keyword(s):  
Surface Energy ◽  
High Density Polyethylene ◽  
Beta Radiation ◽  
Low Density Polyethylene ◽  
Cross Linking ◽  
Bonded Joints ◽  
Adhesive Properties ◽  
High Quality ◽  
Measurement Results ◽  
Untreated Material

In this study there was found that radiation cross-linking increased the surface energy of high-density polyethylene (HDPE), and low-density polyethylene (LDPE). Surface energy affects the wettability of the surface and is very important for creating of high-quality bonded joints. The measurement results indicated that radiation cross-linking was a very effective tool for the improvement of adhesive properties and increased the surface energy of selected polyolefins. Surfaces of selected materials with ionizing beta radiation with doses of 0, 33, 66, 99, 132, 165, and 198 kGy were irradiated. The best results were achieved by irradiation at dose of 165 kGy. The surface energy after irradiation was increased up to 100 % compared to untreated material.

Tensile strength of handsheets prepared with macerated fibres from solid wood modified with cross-linking agents

Holzforschung ◽  
2015 ◽  
Vol 69 (8) ◽  
pp. 959-966 ◽  
Author(s):  
Stergios Adamopoulos ◽  
Reza Hosseinpourpia ◽  
Carsten Mai
Keyword(s):  
Tensile Strength ◽  
Strength Loss ◽  
Solid Wood ◽  
Cross Linking ◽  
Microscopic Appearance ◽  
Finite Span ◽  
The Stability ◽  
And Control ◽  
Additional Role ◽  
Modified Wood

Abstract This study was conducted to explain the tensile strength loss of wood due to the modification with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and glutaraldehyde (GA). Modified and control wood blocks were macerated to deliberate fibres, and handsheets were produced thereof. The nitrogen content of the fibres indicated that maceration removed the major proportions of DMDHEU. The stability of GA in wood during maceration was not assessed. Tensile strength determined at zero span (z-strength) and finite span (f-strength) was equal for the handsheets from DMDHEU-modified fibres and the control handsheets. The microscopic appearance of the tested finite-span paper strips from DMDHEU-modified fibres mainly indicated interfibre failure and did not differ from the fibre fracture mode of the control handsheets. In contrast, the z-strength of the handsheets from GA-modified fibres was lower than that of controls and decreased with increasing content of GA in the initial modified wood. The f-strength behaviour of the handsheets from GA-modified fibres was the opposite: it was higher than that of controls and increased with increasing GA content. The microscopic appearance of the rapture zones of the finite-span testing mainly indicated intrafibre failure for the GA-modified fibres. It was concluded that cross-linking is likely to be the major reason for tensile strength loss of GA- and DMDHEU-modified wood. In terms of DMDHEU-modified wood, the incrustation of the cell wall by the resin and the reduction in pliability could play an additional role.

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