Bond Strength–Disbonding Behavior and Dimensional Stability of Walnut and Poplar Impregnated with Some Chemicals and Bonded with PVAc, VTKA and Urea Formaldehyde

2011 ◽  
Vol 25 (9) ◽  
pp. 949-969
Author(s):  
Hamiyet Şahin Kol ◽  
Şeref Kurt ◽  
Burhanettin Uysal
Keyword(s):  
Bond Strength ◽  
Dimensional Stability ◽  
Urea Formaldehyde

Tensile shear strength of UF- and MUF-bonded veneer related to data of adhesives and cell walls measured by nanoindentation

Holzforschung ◽  
2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Frank Stöckel ◽  
Johannes Konnerth ◽  
Wolfgang Kantner ◽  
Johann Moser ◽  
Wolfgang Gindl
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Bond Strength ◽  
Cell Walls ◽  
Urea Formaldehyde ◽  
Lap Joints ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Interphase Cell ◽  
Cure Time

Abstract The tensile shear strength of veneer lap joints was characterised. The joints were produced with an Automated Bonding Evaluation System (ABES) using urea-formaldehyde (UF) as well as melamine-urea-formaldehyde (MUF) adhesive formulated for particleboard production. At a fixed heating temperature of 110°C, a systematic increase in bond strength was observed for both adhesives with increasing cure time. The absolute bond strength was significantly higher for MUF compared to UF. Nanoindentation experiments with the same specimens used for ABES revealed a very hard, stiff and brittle character of the UF resin, whereas the MUF proved significantly less hard and stiff, and less brit-tle. Wood cell walls in contact with adhesive, i.e., where adhesive penetration into the cell wall was assumed, showed significantly altered mechanical properties. Such cell walls were harder, stiffer and more brittle than unaffected reference cell walls. These effects were slightly more pronounced for UF than for MUF. Comparing UF and MUF, the micro-mechanical properties of cured adhesive and interphase cell walls confirm earlier observations that tougher adhesives can lead to higher macroscopic bond strength. In strong contrast to that, no obvious correlation was found between micromechanical properties and the strong cure time dependence of macroscopic bond strength.

Preparation and Characteristic of Urea Formaldehyde Modified with Hexamethoxymethyl Melamine

2010 ◽  
Vol 160-162 ◽  
pp. 1245-1252
Author(s):  
Zhen Zhong Gao ◽  
Li Tao Guan ◽  
Jin Sun ◽  
Deng Yun Tu
Keyword(s):  
Bond Strength ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Solidification Time ◽  
Uf Resin ◽  
Optimum Formulation ◽  
Chinese Standard

Hexamethoxymethyl melamine (HMMM) was used to modify UF resins to obtain good performance with low formaldehyde emission. The effect of urea to formaldehyde ratio, HMMM content on the properties of UF resin was studied in detail. The results suggested that urea to formaldehyde ratio to be 1:0.9 and 20% HMMM content is the optimum formulation to afford desired UF resin. The viscosity, solidification time, bond strength and formaldehyde emission of the modified UF resins were also studied. The results revealed that the performance of the modified UF achieved the chinese standard.

scholarly journals Potential Use of Wollastonite as a Filler in UF Resin Based Medium-Density Fiberboard (MDF)

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1435 ◽  
Author(s):  
Hamid R. Taghiyari ◽  
Ayoub Esmailpour ◽  
Roya Majidi ◽  
Jeffrey J. Morrell ◽  
Mohammad Mallaki ◽  
...  
Keyword(s):  
Bond Strength ◽  
Internal Bond ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Medium Density ◽  
Environmental Footprint ◽  
Positive Effects ◽  
Uf Resin ◽  
Resin Curing ◽  
Potential Use

Urea-formaldehyde (UF) resins are primary petroleum-based, increasing their potential environmental footprint. Identifying additives to reduce the total amount of resin needed without adversely affecting the panel properties could reduce these impacts. Wollastonite is a mineral containing calcium and silica that has been used as an additive in a variety of materials and may be useful as a resin extender. Nanoscale wollastonite has been shown to enhance the panel properties but is costly. Micron-scale wollastonite may be a less costly alternative. Medium-density fiberboards were produced by blending a hardwood furnish with UF alone, micron-sized wollastonite alone, or a 9:1 ratio of UF to wollastonite. Panels containing of only wollastonite had poor properties, but the properties of panels with 9:1 UF/wollastonite were similar to the UF-alone panels, except for the internal bond strength. The results suggest that small amounts of micron-sized wollastonite could serve as a resin extender. Further studies are suggested to determine if the micron-sized material has similar positive effects on the resin curing rate.

scholarly journals Research on the Properties of High-strength Gypsum Based Tile Adhesive in Interior Decoration

2020 ◽  
Vol 165 ◽  
pp. 05015
Author(s):  
Ji Xiu Zhang ◽  
Ye Zhang ◽  
Ji Kang Liu ◽  
Yuan Chao Miao ◽  
Sai Hong Duan
Keyword(s):  
Bond Strength ◽  
Dimensional Stability ◽  
High Strength ◽  
High Dimensional ◽  
Strength Development ◽  
Interior Decoration ◽  
High Bond ◽  
High Bond Strength ◽  
Early Strength ◽  
Interface Treatment

In this paper, a new early strength tile adhesive is prepared by using α- high strength gypsum and its properties are discussed. The research methods refer to relevant Chinese standards. The results show that the tensile bond strength of the adhesive can reach 0.6 MPa in one day and 1.5 MPa in 7 days, which is close to 80% of 28-day strength. It is indicating that the adhesive has high bond strength, rapid strength development, and high dimensional stability. It effectively solves the problems that the traditional cement-based tile adhesive is prone to hollowing, falling off, and cracking. Additionally, no interface treatment is required during the using process of this gypsum-based adhesive.

Dimensional Stability, Mechanical Properties and Fire Resistance of MUF-Boron Treated Wood

2011 ◽  
Vol 341-342 ◽  
pp. 80-84 ◽  
Author(s):  
Yu Bo Chai ◽  
Jun Liang Liu ◽  
Xing Zhen
Keyword(s):  
Mechanical Properties ◽  
Boric Acid ◽  
Fire Resistance ◽  
Dimensional Stability ◽  
Urea Formaldehyde ◽  
Treated Wood ◽  
Weight Percent ◽  
Wood Modification ◽  
Treatment Conditions

In order to improve the dimensional stability, mechanical properties and fire resistance of the wood from Cryptomeria fortunei, the melamine-urea-formaldehyde (MUF) resin and the mixture of MUF/boric acid/borax (MBB) were prepared and used as the wood modification solution. Results show that both the MUF resin and the MBB solutions exhibit good permeability to wood. Under the same treatment conditions, the weight percent gains (WPG) of treated wood increases with the increasing concentration of modification solutions. MUF and MBB modification solutions can effectively enhance the dimensional stability, MOR, MOE and fire resistance of wood. Compared with MBB treated wood, MUF treated wood exhibits higher MOR and dimensional stability. The MBB treated wood has higher MOE and fire resistance than MUF treated wood.

scholarly journals Particleboard Manufactured from Rubberwood RRIM 2002 Clone Planted with Different Fertilizer Treatment

2019 ◽  
Vol 8 (2S4) ◽  
pp. 398-402
Keyword(s):  
Dimensional Stability ◽  
Cold Water ◽  
Urea Formaldehyde ◽  
Rubber Tree ◽  
Modulus Of Rupture ◽  
Normal Rate ◽  
Fertilizer Treatment ◽  
Internal Bonding ◽  
Japanese Industrial Standard ◽  
Npk Fertilizer

This work focus on the effects of SRF (Slow Release Fertilizer) + NPK fertilizer rates on the properties of rubberwood particleboards produced. The particleboards were fabricated using rubber tree trial clone RRIM 2002. RRIM 2002 clone still in trial plot with age of 4-year old and classified as Latex Timber Clone which estimated to produce large wood volume and also better latex yield. The properties of particleboard were categorized and evaluated based on fertilizer treatment applied on RRIM 2002 clone tree: T1 (SRF + NPK at normal rate), T2 (SRF + 1.5 x NPK at normal rate), T3 (SRF + 2.0 x NPK at normal rate) and T4 (SRF + 2.5 x NPK at normal rate, control (NPK at normal rate). The resin used for particleboard fabrication was urea formaldehyde (UF) (63.9% solid) type E1. The resin content is 10%. The thickness of board is 10 mm with density 700 kgm-3 . The particleboards were fabricated and assessed in accordance to Japanese Industrial Standard for Particleboard (JIS A 5908-2003). The properties that been assessed were on modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB), thickness swelling (TS) and water absorption (WA). From this study, it is found that fertilizer treatment influences the particle recovery and performance of particleboard especially on dimensional stability and internal bonding properties which significantly affected. The MOR and MOE of particleboard made from rubber trees that treated with SRF-NPK fertilizer showed better performance compared to that of with NPK fertilizer alone (control), however, the differences were not significant. In term of IB, no specific trend was observed. Lastly, for dimensional stability (TS and WA), particleboard produced from SRF-NPK fertilizer reduced the board stability when subjected to cold water soak.

Impact of pressing regime and substrate type on bond quality of decorative veneer

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2668-2679
Author(s):  
Vladislav Zdravković ◽  
Tanja Palija ◽  
Aleksandar Lovrić ◽  
Anđela Obradović
Keyword(s):  
Multivariate Analysis ◽  
Bond Strength ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Medium Density ◽  
Substrate Type ◽  
Bond Quality ◽  
The Impact ◽  
Moisture Resistant

The choice of optimal pressing regime for certain types of substrate is of great importance in production of veneered panels. In this paper, the impact of pressing regime on the bonding strength of beech and oak veneers, glued with urea-formaldehyde (UF) adhesive, on medium-density fiberboard (MDF), and moisture-resistant MDF (MR MDF) substrates was examined. The analyses showed a generally higher bond strength with oak veneer compared to beech veneer, which was also the case with regular MDF compared to moisture-resistant MDF. Multivariate analysis of variance (ANOVA) showed that with beech veneer, all of the used regimes produced better results on regular MDF compared to moisture-resistant MDF. In contrast, with oak veneer, the influence of pressing regime had a more noteworthy impact than the type of substrate used. These results indicated that the use of MR MDF as substrate in combination with UF adhesive was inadequate.

Chemical, physico-mechanical properties and biological durability of rubberwood particleboards after post heat-treatment in palm oil

Holzforschung ◽  
2018 ◽  
Vol 72 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Seng Hua Lee ◽  
Zaidon Ashaari ◽  
Wei Chen Lum ◽  
Aik Fei Ang ◽  
Juliana Abdul Halip ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Palm Oil ◽  
Dimensional Stability ◽  
Urea Formaldehyde ◽  
Chemical Properties ◽  
Water Repellency ◽  
Post Heat Treatment ◽  
Termite Resistance ◽  
Biological Durability

AbstractThe chemical properties, dimensional stability, mechanical strength and termite resistance of urea formaldehyde (UF) bond rubberwood (RW) particleboard (PB) were assessed after a two-step oil heat treatment (OHT). The PB was immersed in palm oil before heating to 180, 200, and 220°C in a laboratory oven for 2 h. Anti-swelling efficiency (ASE) and water repellency efficiency (WRE) as well as bending (MOE, MOR) and internal bonding strength (IB) were determined. Resistance against a subterranean termite,Coptotermes curvignathusHolmgren, was tested. The degradation of hemicelluloses and cellulose, that are mainly responsible for wood wetting processes, was confirmed by Fourier transform infrared (FTIR) spectra. Formation of an elevated cross-linking density in lignin also contributed to the dimensional stability, where 93.6% ASE and 46.3% WRE were achieved in the samples treated at 220°C. Mechanical properties of treated samples were inferior to the control samples due to hemicelluloses degradation and breakage of the UF bonding network. A significant improvement in termite resistance has been found in the treated samples.

NaOH Treatment Impact in the Dimensional Stability of Banana Pseudostem Particleboard Panels

2014 ◽  
Vol 600 ◽  
pp. 447-451 ◽  
Author(s):  
Bárbara Maria Ribeiro Guimarães ◽  
Lina Bufalino ◽  
José Benedito Guimarães Jr. ◽  
Rafael Farinassi Mendes ◽  
Lourival Marin Mendes ◽  
...  
Keyword(s):  
Water Absorption ◽  
Dimensional Stability ◽  
Urea Formaldehyde ◽  
Thickness Swelling ◽  
Technical Feasibility ◽  
Pressing Cycle ◽  
Naoh Treatment

This work intends to verify the technical feasibility of NaOH treatment in particleboard manufacture made from banana pseudostem fibers. The particles were treated for a 24 hour period and subsequently washed with water to remove the product. The concentration used was NaOH at 0.5%. The adhesive used was urea - formaldehyde at 12%, the pressing cycle was 4 MPa, at 160 °C for 8 minutes. The water absorption after 2 hours immersion was 148.79% and 189.83% after 24 hours. Thickness swelling value after 2 hours was 54.96% and 74.05% after 24 hours. The results were above the literature values and the minimum values required by the CS 236-66 standard for swelling after 24 hours immersion.

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