Chemical and Physical Changes for Dimensionally Stability of Compressed Wood

2010 ◽  
Vol 129-131 ◽  
pp. 46-49 ◽  
Author(s):  
Guo Feng Wu ◽  
Yi Fei Jiang ◽  
Hao Zhang ◽  
Bin Wang ◽  
He Yu Chen ◽  
...  
Keyword(s):  
Urea Formaldehyde ◽  
Chemical Modifier ◽  
Poplar Wood ◽  
Hot Press ◽  
Dimension Stability ◽  
Hydroxyl Absorption ◽  
Natural Wood ◽  
Ftir Spectrometer ◽  
Physical Changes ◽  
Compressed Wood

The objective of this study was to determine the chemical and physical changes of chemical modified on poplar wood. The chemical modifier was impregnated into cell lumen space by pulse-dipping machine to improve the dimension stability and mechanical property of timber. The timbers were compressed and dried by the multilayer hot-press drying to produce the modified timber. The modified timber had better dimension stability than the natural wood when they were immerged water continuous eight-hour. Characteristics of Fourier Transform Infrared Spectroscopy (FTIR) for modified were studied by the FTIR spectrometer. The intensity of hydroxyl absorption peak in the infrared absorption spectrogram decreased significantly, and that of carbonyl decreased lightly, which due to the bond of the function groups of -NHCH2OH of urea-formaldehyde prepolymer react with the wood carboxyl (C=O) and hydroxyl(-OH). The morphologic models of chemical within wood were discovered by SEM.

Study on Compressed Wood with Urea-Formaldehyde Prepolymer

2011 ◽  
Vol 675-677 ◽  
pp. 411-414
Author(s):  
Guo Feng Wu ◽  
Yi Fei Jiang ◽  
Ping Qu ◽  
Sheng Yao ◽  
Jun Wen Pu
Keyword(s):  
Dimensional Stability ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Degree Of Crystallinity ◽  
Hot Press ◽  
Drying Treatment ◽  
Compressed Wood ◽  
Modified Wood

In this research, the urea-formaldehyde prepolymer and multilayer hot-press drying was used to obtain modified wood. The timbers were compressed and dried by the multilayer hot-press drying kiln. The combination of chemical modification and hot-press drying can improve the drying rate, which can also enhanced the physical and mechanical properties. Based on the findings, the basic density of modified wood improved 25.2 %, the bending strength and the bend elastic modulus improved 15.6 % and 25.0 % respectively. The dimensional stability of the treatment appeared to be slightly higher than that of untreated samples under the same conditions for processing temperatures and times. The improving dimensional stability of wood mainly was attributed to the prepolymer that changes wood cell wall components such as the degradation of the hemicelluloses and cellulose during hot-press drying treatment. The XRD results indicated that the degree of crystallinity increased to 35.45 %from 31.25 %. The TGA results show that the degradation of the samples can be divided into two step, both of the maximum weight loss velocity temperature of the two step increased to 266 °C, 355 °C from 244 °C and 341 °C.

Study on Urea-Formaldehyde Prepolymer and Hot-Press Treatment of Italian Poplar Wood

2012 ◽  
Vol 62 (5) ◽  
pp. 406-411
Author(s):  
Guofeng Wu ◽  
Yifei Jiang ◽  
Ping Qu ◽  
Shuping Song ◽  
Junwen Pu
Keyword(s):  
Urea Formaldehyde ◽  
Poplar Wood ◽  
Hot Press

Chemical Modification of Poplar Wood on the Mechanical Properties

2011 ◽  
Vol 194-196 ◽  
pp. 1815-1818
Author(s):  
Guo Feng Wu ◽  
Qian Lang ◽  
Bin Wang ◽  
Yi Fei Jiang ◽  
Jun Wen Pu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Compressive Strength ◽  
Chemical Modification ◽  
Water Absorption ◽  
Bending Strength ◽  
Poplar Wood ◽  
Hot Press ◽  
Drying Treatment ◽  
Natural Wood

In this research, the chemical and multilayer hot-press drying was used to modify poplar wood. The timbers were compressed and dried in the multilayer hot-press drying kiln. The combination of chemical modification and hot-press drying can improve the mechanical properties. The influence of chemical and hot-press drying on the compressive strength parallel to grain, the bending strength, the density, the water absorbent and the crystallinity of poplar wood have been investigated in this study. The chemical treated conditions close to real technological regimes selected. The samples were impregnated with three conditions. The samples were dried in a hot-press drying kiln for 130hrs. It was showed that the urea carbamate and hot-press drying treatment increase the properties. The density and mechanical properties increased with increasing urea carbamate, while the water absorption decreased. The crystallinity is 37.03%, 37.11%, 37.78%, separately, compared with the natural wood of 35.09%. The TAG showed the thermal stability increased.

scholarly journals Eco-Friendly, High-Density Fiberboards Bonded with Urea-Formaldehyde and Ammonium Lignosulfonate

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 220
Author(s):  
Petar Antov ◽  
Viktor Savov ◽  
Ľuboš Krišťák ◽  
Roman Réh ◽  
George I. Mantanis
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
High Density ◽  
Thickness Swelling ◽  
Formaldehyde Content ◽  
Uf Resin ◽  
Natural Wood ◽  
European Standards

The potential of producing eco-friendly, formaldehyde-free, high-density fiberboard (HDF) panels from hardwood fibers bonded with urea-formaldehyde (UF) resin and a novel ammonium lignosulfonate (ALS) is investigated in this paper. HDF panels were fabricated in the laboratory by applying a very low UF gluing factor (3%) and ALS content varying from 6% to 10% (based on the dry fibers). The physical and mechanical properties of the fiberboards, such as water absorption (WA), thickness swelling (TS), modulus of elasticity (MOE), bending strength (MOR), internal bond strength (IB), as well as formaldehyde content, were determined in accordance with the corresponding European standards. Overall, the HDF panels exhibited very satisfactory physical and mechanical properties, fully complying with the standard requirements of HDF for use in load-bearing applications in humid conditions. Markedly, the formaldehyde content of the laboratory fabricated panels was extremely low, ranging between 0.7–1.0 mg/100 g, which is, in fact, equivalent to the formaldehyde release of natural wood.

Effect of Palm Kernel Meal as Melamine Urea Formaldehyde Adhesive Extender for Plywood Application: Using a Fourier Transform Infrared Spectroscopy (FTIR) Study

2011 ◽  
Vol 121-126 ◽  
pp. 493-498 ◽  
Author(s):  
Huei Ruey Ong ◽  
Reddy Prasad ◽  
Md. Maksudur Rahman Khan ◽  
Md. Najmul Kabir Chowdhury
Keyword(s):  
Fourier Transform ◽  
Functional Groups ◽  
Chemical Interaction ◽  
Urea Formaldehyde ◽  
Palm Kernel ◽  
Fourier Transform Infrared ◽  
Blue Shift ◽  
Hot Press ◽  
Kernel Meal ◽  
Palm Kernel Meal

Increased demand for wood adhesives, environmental concerns, and the uncertainty of continuing availability of petrochemicals have led to recent attention on protein-based adhesives. This study was conducted to investigate the physico-chemical interaction of palm kernel meal (PKM) with melamine urea formaldehyde (MUF) resins in adhesive formulation by using Fourier Transform Infrared (FTIR) Spectroscopy. The effect of hot press on PKM extender has been investigated by FTIR and blue shift is observed due to the hot press indicating that the functional groups (such as C=O, -OH and NH) are become more free in the samples. In the case of PKM-MUF blend bonding interactions observed where, PKM played the role as an extender. Red shift of C=O and N-H groups stretching in PKM-MUF-Wood blend is observed which suggests the interaction of these functional groups through hydrogen bonding. The results suggest that PKM extender-based MUF adhesive resins have potential application for the production of exterior plywood.

Effect of calcite addition on technical properties and reduction of formaldehyde emissions of medium density fiberboard

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3718-3733
Author(s):  
Osman Camlibel
Keyword(s):  
Liquid Paraffin ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Formaldehyde Emission ◽  
Modulus Of Rupture ◽  
Medium Density ◽  
Wood Fibers ◽  
Hot Press ◽  
Ammonium Sulphate Solution ◽  
Hot Press Process

Physical, mechanical, and formaldehyde emission properties were studied for medium density fiberboard (MDF) produced with oak (75%) and pine (25%) fibers that had been mechanically refined in the presence of calcite particles. The calcite slurry was prepared at two levels of solids, 1.5% and 3% (10 and 20 kg·m-³). Chips were cooked for 4 min at 185 °C, under 8 bar vapor pressure in an Andritz defibrillator. 1.8% liquid paraffin, 0.72% ammonium sulphate solution, and 11% urea-formaldehyde were added by percentage based on oven-dried wood fibers in the blowline at the exit of the defibrator. The fibers were dried to 11% moisture content. MDF boards (2100 mm × 2800 mm × 18 mm) were created using a continuous hot-press process. The addition of calcite in the course of MDF production resulted in improved physical properties, such as thickness swelling (ThS 24 hours) and water absorption (WA 24 hours). MDF boards prepared with calcite exhibited higher internal bond (IB), modulus of rupture (MOR), and modulus of elasticity (MOE). Resistance to axial withdrawal of screw also was increased by addition of 3% calcite. In addition, the lowest levels of formaldehyde emission were observed for MDF prepared with calcite at the 3% level.

Decrease in the deflection of the furniture boards revetted paper and layered plastic

2015 ◽  
Vol 5 (4) ◽  
pp. 152-161
Author(s):  
Кантиева ◽  
Ekaterina Kantieva ◽  
Разиньков ◽  
Egor Razinkov ◽  
Сладких ◽  
...  
Keyword(s):  
Working Conditions ◽  
Polyvinyl Acetate ◽  
Urea Formaldehyde ◽  
Longitudinal Direction ◽  
Formaldehyde Resin ◽  
Hot Press ◽  
Combined Design ◽  
Kitchen Table ◽  
Wood Shaving ◽  
Polyvinyl Acetate Dispersion

One of the main objectives of the enterprises for production of furniture is decrease in a material capacity of production and as a result decrease in its prime cost. Producers of kitchen table-tops for this purpose pass to production of table-tops of the combined design, replacing thick wood-shaving plates 25, 38 mm thick, with thinner 16 mm.For maintenance of more massive appearance of such table-tops to thin wood chipboard in the longitudinal direction at the edges of a board paste longitudinal strips from chipboard. The economy of material can lead to a deflection, the received table-tops. In this work the deflection of table-tops of the combined design was investigated. For studying of the reasons of emergence of a deflection and ways of its decrease the samples received in laboratory and working conditions were investigated. For pasting of boards from chipboard the paper and layered plastic used glue on the basis of polyvinyl acetate dispersion and the combined glue with various ratio of urea-formaldehyde resinand polyvinyl acetate dispersion. At the first stage defined a deflection of not revertedwood-shaving plates. Then controlled change of a deflection after gluing of plastic, paper from the back (and, paper and plastic made a veneering consistently and at the same time), after gluing of levels from chipboard. The deflection was defined in various directions of a furniture board in dynamics. Determined durability of gluing of plastic by above-mentioned glues. As a result of work it is established that the veneering of the front and reverse parties of plates in a hot press needs to be made at the same time. By production of the combined design of table-tops it is more expedient to use pure polyvinyl acetate dispersion. Durability on a plastic separation from wood-shaving plates is higher when using of the mixed glue on the basis of polyvinyl acetate dispersion and urea-formaldehyde resin.

Optimization of Processing Variables in Wheat Straw Particleboard for Manufacturing Pallets

2012 ◽  
Vol 200 ◽  
pp. 335-338 ◽  
Author(s):  
Peng Luo ◽  
Chuan Min Yang ◽  
Hong Wei Ji
Keyword(s):  
Wheat Straw ◽  
Steam Explosion ◽  
High Performance ◽  
Low Cost ◽  
Urea Formaldehyde ◽  
National Standard ◽  
Hot Press ◽  
Board Density ◽  
Press Temperature ◽  
Uf Resin

The goal of this work was to make particleboards for manufacturing pallets from wheat straw using low cost urea formaldehyde (UF) resin adhesive. The wheat straws were subject to steam explosion pretreatment to improve bondability with UF resin. Particleboards were obtained from the steam explosion pretreated wheat straws with UF resin. Particleboard manufacturing parameters, such as pressing time, temperature and board density, were optimized to achieve high performance panel board for pallets. The optimum parameters were found to be: hot press temperature 170 °C, hot press time 40 s/mm, resin application ratio 10%, and straw particle size 12 mm. Under the optimum conditions particleboards met the mechanical requirements for the industrial use particleboards based on the Chinese National Standard for Particleboard and were able to make pallets.

Sound Absorption Coefficients Natural Fibre Reinforced Composites

2013 ◽  
Vol 701 ◽  
pp. 53-58 ◽  
Author(s):  
Elammaran Jayamani ◽  
Sinin Hamdan
Keyword(s):  
Sound Absorption ◽  
Urea Formaldehyde ◽  
Weight Fraction ◽  
Natural Fibre ◽  
Solid Content ◽  
Formaldehyde Resin ◽  
Hot Press ◽  
Absorption Coefficients ◽  
Kenaf Core ◽  
Core Fibre

In this Investigation, the influence of two kind of polymers (Urea-formaldehyde and Polypropylene) mixed with natural fibre (Kenaf) were studied for their sound absorption coefficients. Four samples were made; Samples A1 and A2 are made of Kenaf core fibre with adhesive of high emission Urea-formaldehyde resin (HN 100) with 51.6 % solid content. The fabrication of the particle board was done using a hot press for 6 minutes under the pressure of 40 Ton at 180°C for different fibre lengths 1 mm (Sample A1) and 0.6 mm (Sample A2) with weight fraction of 80%. Sample B1 and B2 are made of Kenaf core fibre with polypropylene matrix materials with coupling agent of polyvinyl alcohol. The fabrication of the sample was done using hot press for 30 minutes under the pressure of 1000 Psi at 180°C for different lengths of 1 mm (Sample B1) and 0.6 mm (Sample B2) with weight fraction of 20%. The sound absorption coefficients of samples were measured according to American society for Testing Materials (ASTM E1050 10) two microphone method. It is evident that type of polymer influences the sound absorption coefficients.

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