scholarly journals Effects of Selected Parameters on the Bonding Quality and Temperature Evolution Inside Plywood During Pressing

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1035 ◽  
Author(s):  
Pavlo Bekhta ◽  
Ján Sedliačik ◽  
Nataliya Bekhta
Keyword(s):  
Heating Rate ◽  
Phenol Formaldehyde ◽  
Temperature Evolution ◽  
Efficient Production ◽  
Pressing Pressure ◽  
Bonding Quality ◽  
Pressing Time ◽  
Temperature Time ◽  
Required Quality

This research optimizes the process of plywood production to determine its effectiveness in reducing energy and adhesive consumption for more efficient production with the required quality. The influence of selected parameters including veneer treatment (non-densified and densified), plywood structure, temperature, time and pressure of pressing, on the bonding quality and temperature evolution within the veneer stacks during hot pressing was investigated. Rotary-cut, non-densified and densified birch veneers and phenol formaldehyde (PF) adhesive were used to manufacture plywood samples. The effect of pressure and time of pressing on bonding quality of the plywood was determined. Bonding quality was evaluated by determining the shear strength of the plywood samples. The temperature evolution inside the veneer stacks was measured for birch veneers for different pressing temperatures and pressures for different numbers of veneer layers. The heating rate of the veneer stacks increased as the pressing temperature increased and decreased markedly with an increasing number of veneer layers. At a high pressing pressure, the heating rate of the densified veneer stacks was faster than that of non-densified veneers at the same pressure. The use of densified veneers for the production of plywood can lead to a shorter pressing time (17–50% reduction), lower glue consumption (33.3% reduction) and a lower pressing pressure (22.2% reduction) without negatively impacting the bonding strength of the plywood.

scholarly journals Environmentally-Friendly High-Density Polyethylene-Bonded Plywood Panels

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1166 ◽  
Author(s):  
Pavlo Bekhta ◽  
Ján Sedliačik
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
High Density Polyethylene ◽  
Phenol Formaldehyde ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Core Layer ◽  
High Density ◽  
Pressing Pressure ◽  
Pressing Time

Thermoplastic films exhibit good potential to be used as adhesives for the production of veneer-based composites. This work presents the first effort to develop and evaluate composites based on alder veneers and high-density polyethylene (HDPE) film. The effects of hot-pressing temperature (140, 160, and 180 °C), hot-pressing pressure (0.8, 1.2, and 1.6 MPa), hot-pressing time (1, 2, 3, and 5 min), and type of adhesives on the physical and mechanical properties of alder plywood panels were investigated. The effects of these variables on the core-layer temperature during the hot pressing of multiplywood panels using various adhesives were also studied. Three types of adhesives were used: urea–formaldehyde (UF), phenol–formaldehyde (PF), and HDPE film. UF and PF adhesives were used for the comparison. The findings of this work indicate that formaldehyde-free HDPE film adhesive gave values of mechanical properties of alder plywood panels that are comparable to those obtained with traditional UF and PF adhesives, even though the adhesive dosage and pressing pressure were lower than when UF and PF adhesives were used. The obtained bonding strength values of HDPE-bonded alder plywood panels ranged from 0.74 to 2.38 MPa and met the European Standard EN 314-2 for Class 1 plywood. The optimum conditions for the bonding of HDPE plywood were 160 °C, 0.8 MPa, and 3 min.

scholarly journals Possibilities of using hydrolytic lignin in the production of wood-splicing materials

2021 ◽  
Vol 244 ◽  
pp. 04006
Author(s):  
Nikolay Plotnikov ◽  
Galina Plotnikova ◽  
Natalia Vaynshtok
Keyword(s):  
Phenol Formaldehyde ◽  
Environmental Safety ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Regression Equations ◽  
Pressing Pressure ◽  
Pressing Time ◽  
Hydrolytic Lignin ◽  
Hydrolyzed Lignin ◽  
Sufficient Degree

The problem of improving the environmental safety of the waste management system of chemical processing of biomass of wood is quite acute in every forest producing and timber processing region. Study of the possibility of using to investigate hydrolytic lignin as a modifier of phenol-formaldehyde resin for the production of plywood have been conducted. Used materials: phenol-formaldehyde resin SFZh-3013; technical hydrolyzed lignin. Mathematical models of the process of pressing glued plywood were developed and the optimal parameters for the production of plywood were determined based on the use of SFZh-3013 resin modified with hydrolytic lignin. The optimal mode of pressing is: the amount of injected hydrolytic lignin in the SFZh-3013 resin grade is 5-10 parts by weight; pressing pressure 1.6 MPa, pressing temperature 135 °C and pressing time 9-10 minutes. The introduction of regimes developed using regression equations, with a sufficient degree of accuracy describing the pressing process, will significantly improve the efficiency of plywood production by saving energy and material costs and preserving product quality.

scholarly journals Physical properties and bonding quality of laminated veneer lumber produced with veneers peeled from small-diameter rubberwood logs

2019 ◽  
Vol 6 (12) ◽  
pp. 191763 ◽  
Author(s):  
P. S. Khoo ◽  
K. L. Chin ◽  
P. S. H'ng ◽  
E. S. Bakar ◽  
C. L. Lee ◽  
...  
Keyword(s):  
Phenol Formaldehyde ◽  
Small Diameter ◽  
Lower Grade ◽  
Bonding Quality ◽  
Laminated Veneer Lumber ◽  
Short Rotation ◽  
Different Temperatures ◽  
Lamination Process ◽  
Lathe Check

The peeling of small-diameter rubberwood logs from the current short-rotation practices undoubtedly will produce lower grade veneers compared to the veneers from conventional planting rotation. Hence, this raises the question of the properties of the produced laminated veneer lumber (LVL) from veneers peeled from small-diameter rubberwood logs using the spindleless lathe technology. Different thicknesses of rubberwood veneers was peeled from rubberwood logs with diameter less than 20 cm using a spindleless lathe. Three-layer LVLs were prepared using phenol formaldehyde (PF) adhesive and hot pressed at different temperatures. During the peeling of veneer, lathe checks as deep as 30–60% of the veneer thickness are formed. Owing to deeper lathe check on 3 mm rubberwood veneer, higher pressing temperature significantly increased the gluebond shear strength of the PF-bonded LVL. In addition, lathe check frequency was also shown to influence the bond strength. The presence of higher lathe check frequency on 2 mm veneer increased the wettability, thus facilitating optimum penetration of adhesive for stronger bonding. These findings stress the importance of measuring and considering the lathe check depth and frequency during the lamination process to get a better understanding of bonding quality in veneer-based products.

scholarly journals Production of plywood panels from Pinus taeda using veneers of differing densities and phenol-formaldehyde resin with high and low molecular weights

CERNE ◽  
2013 ◽  
Vol 19 (2) ◽  
pp. 315-321
Author(s):  
Graciela Ines Bolzon de Muniz ◽  
Setsuo Iwakiri ◽  
Lívia Cássia Viana ◽  
Mário Andrade ◽  
Cristiane Weber ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pinus Taeda ◽  
Cold Water ◽  
Phenol Formaldehyde ◽  
Water Immersion ◽  
Line Strength ◽  
Formaldehyde Resin ◽  
Low Molecular Weight ◽  
Bonding Quality

This study aimed to evaluate the bonding quality of plywood panels from Pinus taeda using low and high molecular weight phenol-formaldehyde resin and veneers from three different density classes. The experiment consisted of six treatments, each of which produced three panels (replicates). Tests were conducted to evaluate glue line strength to shear stress after two boiling cycles and after 24 hours of cold water immersion. Also determined was the percentage of defects in wood samples. Results indicated that the density classes being assessed differed statistically. However, no significant difference was found between panels produced with high and panels produced with low molecular weight resin as to the mean values of glue line strength, whether subjecting them to two boiling cycles or after 24 hours of cold water immersion. Interactions between different density classes and adhesive formulations were found not significant either. Low molecular weight resin (BPM) and panels produced with higher density veneers were found to have better behavior, regarding both bonding strength and percentage of defects. It was concluded that the bonding quality of plywood panels from Pinus taeda was satisfactory after using different densities of veneer and also high and low molecular weight phenolic resins. All treatments were found to comply with minimum requirements established in European standard EN 314-1/1993, which addresses bonding quality of plywood panels.

scholarly journals Optimization of bonding parameters of laminated wood using a novel bio-based RPF adhesive

2019 ◽  
Vol 275 ◽  
pp. 01025
Author(s):  
Xueyong Ren ◽  
Yinlan Shen ◽  
Ying Gao ◽  
Derong Zhang ◽  
Jianmin Chang
Keyword(s):  
Process Parameters ◽  
Phenol Formaldehyde ◽  
Green Manufacturing ◽  
Pressing Pressure ◽  
Curing Agent ◽  
Pyrolysis Oil ◽  
Cold Pressing ◽  
Bonding Parameters ◽  
Pressing Time ◽  
Wood Bonding

Adhesive is the key component and factor for the manufacture of glulam, affected both the properties and cost of glulam product. Bio-based resorcinol-phenol-formaldehyde (BRPF) resin was developed by partly replacing the expensive resorcinol and phenol with the cheap biomass derived pyrolysis oil. The press process parameters and the dosage of adhesive and corresponding curing agent were selected as the factors and extensively studied. BRPF resin was successfully used to bond the laminas to produce glulam, and the optimized process parameters for the cold-pressing adhesion of BRPF resin with pine wood were obtained as follows: the cold-pressing pressure 1.4 MPa, the cold-pressing time 9 h, the amount of adhesive coating 320 g/m2, and the proportion of curing agent (poly-formaldehyde) 17%. The mechanical performances of laminated wood bonding with BRPF resin under the optimal condition were further verified. It is believed that the results obtained here will promote the use of bio-based resin in the bonding of laminated wood, and then contribute to the green manufacturing of glulam with lower cost.

Predictive Models for Modulus of Rupture and Modulus of Elasticity of Particleboard Manufactured in Different Pressing Conditions

2017 ◽  
Vol 36 (6) ◽  
pp. 623-634 ◽  
Author(s):  
Sebahattin Tiryaki ◽  
Uğur Aras ◽  
Hülya Kalaycıoğlu ◽  
Emir Erişir ◽  
Aytaç Aydın
Keyword(s):  
Mechanical Properties ◽  
Predictive Models ◽  
Modulus Of Elasticity ◽  
The Other ◽  
Modulus Of Rupture ◽  
Pressing Pressure ◽  
Pressing Temperature ◽  
Pressing Time ◽  
Artificial Neural Network Ann ◽  
Temperature Time

AbstractDetermining the mechanical properties of particleboard has gained a great importance due to its increasing usage as a building material in recent years. This study aims to develop artificial neural network (ANN) and multiple linear regression (MLR) models for predicting modulus of rupture (MOR) and modulus of elasticity (MOE) of particleboard depending on different pressing temperature, pressing time, pressing pressure and resin type. Experimental results indicated that the increased pressing temperature, time and pressure in manufacturing process generally improved the mechanical properties of particleboard. It was also seen that ANN and MLR models were highly successful in predicting the MOR and MOE of particleboard under given conditions. On the other hand, a comparison between ANN and MLR revealed that the ANN was superior compared to the MLR in predicting the MOR and MOE. Finally, the findings of this study are expected to provide beneficial insights for practitioners to better understand usability of such composite materials for engineering applications and to better assess the effects of pressing conditions on the MOR and MOE of particleboard.

Construction Control As A Strategy For Improving The Quality Of Buildings And Structures

2020 ◽  
Keyword(s):  
Quality Control ◽  
Life Cycle ◽  
Construction Control ◽  
Construction Sites ◽  
Actual Problem ◽  
Construction Market ◽  
Construction Products ◽  
Underlying Causes ◽  
Required Quality

In construction production, the safety of constructing buildings and structures is achieved by ensuring the required quality as a result of systematic construction control based on the implementation of a complex of technical, economic and organizational measures at all stages of the object's life cycle. The article deals with the actual problem of improving the quality of construction products-buildings and structures in conjunction with the activities of construction control bodies. The article presents the advanced foreign and domestic experience of ensuring the quality control at the construction sites, providing for the prevention of the underlying causes of defects and increasing the interest of the contractors directly. On the basis of the analysis of the current situation with quality control at the construction market, ways to improve its efficiency by developing a unified system of technological implementation of relevant requirements for the quality of construction products, determining the rational number and business load of construction control engineers, as well as the active activities of self-regulatory organizations in this area are offered.

Conceptual imposings of quality management of system of production of composite materials for it is rocket the space equipment

2017 ◽  
Vol 14 (4) ◽  
pp. 30-38
Author(s):  
V. G. Isaev ◽  
T. N. Antipova
Keyword(s):  
Composite Materials ◽  
Quality Management ◽  
Evaluation Criteria ◽  
Criteria And Indicators ◽  
Properties Of Materials ◽  
A Priority ◽  
Required Quality

Basic provisions of the concept and methodology of production of composite materials for the missile and space equipment are offered. The system of the purposes realizing the principle of a priority of the purposes of the customer is offered. The system of evaluation criteria and indicators of quality of composite materials the realizing interrelation of requirements of the customer to quality of material and dependence of ensuring the required quality on the used technologies is developed. It is shown that for ensuring quality of composite materials for units and the RKT systems first of all it is necessary development of mathematical dependences of properties of materials on parameters of the technological modes in the conditions of obligatory implementation of requirements of the customer.

Influence of Freeze-Drying Modes on the Quality of Live Plague Vaccine

2019 ◽  
Vol 35 (4) ◽  
pp. 73-78
Author(s):  
S.E. Gostischeva ◽  
D.V. Rostovtseva ◽  
G.F. Ivanova ◽  
A.V. Kostrominov ◽  
M.V. Pilipenko
Keyword(s):  
Heating Rate ◽  
Freeze Drying ◽  
Eutectic Point ◽  
Freezing Temperature ◽  
Freezing Time ◽  
Residual Moisture ◽  
High Viability ◽  
Plague Vaccine ◽  
Selection Of

The optimization of the drying schedule has been carried out to improve the quality indicators of the live plague vaccine. Based on the data obtained on the eutectic point of the vaccine suspension, the freezing temperature and freezing time were set to -50 °С and 6-7 h, respectively. A pressure of 40 mTorr over the surface of the drying suspension and 20 mTorr during the desorption were shown to be the best conditions for sublimation. The drying tests with different options for the shelf heating rate, vacuum depth and duration of intermediate temperature indicators were carried out to develop the improved freeze-drying mode providing the selection of the most adapted bacteria. A vaccine lyophilized under the developed conditions has low residual moisture (up to 2%) and high viability index that persists over the whole shelf life. lyophilization, sublimation, eutectic, live plague vaccine, residual moisture, viability

Sign in / Sign up

Export Citation Format

Share Document