scholarly journals Effect of veneer drying process on some technological properties of polystyrene composite plywood panels

2019 ◽  
Vol 70 (4) ◽  
pp. 369-376
Author(s):  
Hasan Ozturk ◽  
Aydin Demir ◽  
Cenk Demirkir ◽  
Gursel Colakoglu

The aim of study was to determine the effect of veneer drying process on some technological properties of polystyrene composite plywood panels. For this reason, 2 mm-thick rotary cut veneers were obtained from beech (Fagus orientalis, Lipsky), Alder (Alnus glutinosa subsp. Barbata) and Scots pine (Pinus sylvestris L.) logs. The veneers obtained from three different wood species were divided into two groups to produce polystyrene composite plywood (PCP) and traditional plywood. While PCP was produced both air dried (at 20 °C) and oven dried (at 110 °C), the veneer sheets for production of traditional plywood were dried at 110 °C until reaching 7 % equilibrium moisture content. Two different types of polystyrene with high density (30 kg/m3) and low density (16 kg/m3) were used as bonding material for PCP panel production. The urea-formaldehyde adhesive was used as a bonding material for traditional plywood panels. Bonding shear strength, bending strength, modulus of elasticity and density of plywood and polystyrene composite plywood panels were investigated. It was found that the technological properties observed in the study of composite plywood panels manufactured with natural dried veneers gave similar results compared to those of composites produced with technical dried veneers.

2019 ◽  
Vol 70 (2) ◽  
pp. 169-174
Author(s):  
Evren Osman Cakiroglu ◽  
Aydin Demir ◽  
Ismail Aydin

The aim of this study was to investigate the use of birch wood, one of the most important wood species used in the plywood industry, especially in Europe, the Nordic countries, Poland, Belarus and Russia as an alternative to beech wood. For this purpose, comparison was made of their economic and technological properties. In five-ply plywood manufacturing, beech (Fagus orientalis Lipsky) and birch (Betula pendula) veneer sheets were used with melamine urea formaldehyde (MUF) and urea formaldehyde (UF) resins. Some mechanical properties such as shear strength, bending strength and modulus of elasticity of plywood panels were conducted according to EN 314-1 and EN 310, respectively. Mean mechanical strength obtained for birch plywood panels was quite above the limit values specified in the related standards. When taking into consideration the annual increment of beech and birch trees in 1 ha and the time they need to reach suitable diameters for the manufacturing of rotary cut veneers, it was calculated that birch trees provide 2.46 times more physical harvesting than beech trees.


BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 3534-3544 ◽  
Author(s):  
Jian Liu ◽  
Kong Yue ◽  
Feng Wang ◽  
Jinhao Wu ◽  
Zhongqiu Tang ◽  
...  

The bonding performance of the phenol-resorcinol-formaldehyde adhesive (PRF) and melamine-urea-formaldehyde adhesive (MUF) with southern pine as substrates at various moisture contents (MC) was evaluated. The results showed that bonding shear strength with MUF and PRF was negatively related to wood MC, and bonding shear strength with MUF was higher than that of the PRF. The bending and tensile strengths of finger-jointed lumber decreased with wood MC. The bending strength of finger-jointed lumber was affected more by wood than adhesive. However, both wood and adhesive exhibited the same important contribution to the tensile strength.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 511
Author(s):  
Roman Réh ◽  
Ľuboš Krišťák ◽  
Ján Sedliačik ◽  
Pavlo Bekhta ◽  
Monika Božiková ◽  
...  

The potential of using ground birch (Betula verrucosa Ehrh.) bark as an eco-friendly additive in urea-formaldehyde (UF) adhesives for plywood manufacturing was investigated in this work. Five-ply plywood panels were fabricated in the laboratory from beech (Fagus sylvatica L.) veneers bonded with UF adhesive formulations comprising three addition levels of birch bark (BB) as a filler (10%, 15%, and 20%). Two UF resin formulations filled with 10% and 20% wheat flour (WF) were used as reference samples. The mechanical properties (bending strength, modulus of elasticity and shear strength) of the laboratory-fabricated plywood panels, bonded with the addition of BB in the adhesive mixture, were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical strength of the plywood with the addition of BB in the adhesive mixture is acceptable and met the European standard requirements. Markedly, the positive effect of BB in the UF adhesive mixture on the reduction of formaldehyde emission from plywood panels was also confirmed. Initially, the most significant decrease in formaldehyde release (up to 14%) was measured for the plywood sample, produced with 15% BB. After four weeks, the decrease in formaldehyde was estimated up to 51% for the sample manufactured with 20% BB. The performed differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and derivative thermogravimetry (DTG), also confirmed the findings of the study. As this research demonstrated, BB as a waste or by-product of wood processing industry, can be efficiently utilized as an environmentally friendly, inexpensive alternative to WF as a filler in UF adhesive formulations for plywood manufacturing.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 220
Author(s):  
Petar Antov ◽  
Viktor Savov ◽  
Ľuboš Krišťák ◽  
Roman Réh ◽  
George I. Mantanis

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.


2012 ◽  
Vol 36 (2) ◽  
pp. 171-176 ◽  
Author(s):  
MM Rahaman ◽  
K Akhter ◽  
D Biswas ◽  
MW Sheikh

Hybrid acacia, produced from natural crossing between two introduced timber species Acacia mangium and A. auriculiformies has been studied for assessing the suitability of plywood and particleboard manufacture. It was found that 1.5 mm thick smooth and figured veneer can be made and dried easily. Three-ply plywood were made using veneer of this species bonded with liquid urea formaldehyde glue of 50% solid content extended with wheat flower and catalyzed (ammonium chloride) with 2% hardener under the specific pressures, viz., 1.05, 1.40 and 1.76 N/mm2 in three replications at 6 minute press time and 120°C press temperature. Dry and wet shear test were conducted on the sample and their shear load at failure per unit area and percentage of wood failure were determined. 1.76 N/mm2 pressure for the manufacture of ply wood is found to be the best. The particleboard was tested for determining the strength and dimensional stability. The bending strength passed the standard specification, tensile strength was found to be low as per Indian standard. DOI: http://dx.doi.org/10.3329/jbas.v36i2.12960 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 171-176, 2012


2015 ◽  
Vol 22 (3) ◽  
pp. 139-141
Author(s):  
Md. Rahaman ◽  
Khurshid Akhter ◽  
S. Hossain ◽  
Md. Islam

Woods of Albizia richardiana has been studied for assessing the suitability for plywood and particleboard manufacture. It was found that 1.5 mm thick smooth and figured veneer can be peeled and dried easily. Three-ply plywood were made using veneer of this species bonded with liquid urea formaldehyde glue of 50% solid content extended with wheat flour and catalyzed (ammonium chloride) with 2% hardener under the three specific pressures, viz,1.05 N/mm2, 1.40 N/mm2, 1.76 N/mm2 in three replications at 6 minute press time and 120°C press temperature. Dry and wet shear test were conducted on the sample and their shear load at failure per unit area and percentage of wood failure were determined. 1.05 N/mm2 pressure for the manufacture of plywood was found to be the best. The physical and mechanical properties of Albizia richardiana wood particleboard were studied. The particleboards were tested for determining the strength and dimensional stability. The tensile strength 0.56N/mm2 passed the British and German standard specification, bending strength (modulus of rupture10.80N/mm2) was found nearest to Indian Standard but low German and British standard specification.


Algologia ◽  
2021 ◽  
Vol 31 (1) ◽  
pp. 80-92
Author(s):  
Y.C. Wong ◽  
◽  
D.N. Roma ◽  

Petroleum-based plastic has been widely used in many industries. However, it takes hundreds of years to degrade and causes widespread pollution to our environment. These problems led to the invention of bioplastics, which were comprised of natural biopolymers made from starch. The production of bioplastics from food-based starches such as tapioca and corn created competition between food and bioplastic production industries. Hence, this research study focuses on producing bioplastic from microalgae residue, which is a non-food based raw material that uses four different types of plasticizers: glycerol, sorbitol, glutaraldehyde and polyethylene glycol (PEG). Microalgae species for identification were obtained from the fish pond at the University Malaysia of Kelantan, before cultivating the species for 14 days. The microalgae residues were extracted through the centrifugation process. Three species were identified under the light microscope, Chlorella sp., Scenedesmus sp. and Monoraphidium sp. The production of bioplastic involved a manual stirring method using a hotplate magnetic stirrer, followed by drying the bioplastic in an oven at 60 oC. Results obtained showed that sorbitol and glycerol from microalgae are suitable to be used as a plasticizer for the production of bioplastic, however glutaraldehyde and PEG are not suitable. Bioplastics that used PEG and glutaraldehyde became cracked and brittle after the drying process. The characterization of bioplastics includes universal tensile testing machines, Fourier-transform infrared analysis and biodegradability tests being processed//undertaken on glycerol-based and sorbitol based bioplastic. Characterization of bioplastics proved that both glycerol and sorbitol have high potential for applications in daily human life. Bioplastics which used sorbitol as a plasticizer could be used in can be applied the production of plastic goods such as toys and household items due to its good resistance toward stress and minimal flexibility. Meanwhile bioplastics which used glycerol as a plasticizer could be applied to the production of plastic bags and plastic food wrap due to its elastic and flexible nature.


Author(s):  
Kobra Tajaddodi Talab ◽  
Mohd. Nordin Ibrahim ◽  
Sergey Spotar ◽  
Rosnita A. Talib ◽  
Kharidah Muhammad

Abstract Glass transition temperatures (Tg) of MR219 rice variety were measured by differential scanning calorimeter (DSC). State diagram was developed and used to evaluate drying process in this study. Glass transition temperatures range of 9.65- 61.79°C were observed for gains with moisture content of 26.8 – 7.4% (w.b.). For mechanical properties and milling test, statistical analysis was performed by using a two factor experiment in completely randomized design (CRD). Two selected factors were drying temperatures at 5 levels (40, 45, 50, 55, and 60°C) and final moisture content (FMC) at 4 levels (10-10.5, 11-11.5, 12-12.5 and 13-13.5%). Three–point bending test was applied to measure the mechanical properties of rice kernel. Generally, bending strength, apparent modulus of elasticity and fracture energy of brown rice kernel increased with decreasing the grain moisture content. Maximum bending strength was 35.69 and 33.64 MPa for 55, and 60°C, respectively. All samples that were dried at 55 and 60°C experienced to go through the glass transition line after reaching their temperature to the room temperature at the end of drying process. The effect of drying temperature, paddy FMC and their interactions on whole kernel percentage (WKP) and mechanical properties were significant (α = 0.05). An inverse relationship was observed between WKP and the percentage of strong kernels for all treatments.


2016 ◽  
Vol 852 ◽  
pp. 1482-1487
Author(s):  
Fan Cheng ◽  
Yu Hao Jiang ◽  
Jin Bo Chen ◽  
Peng Bo Lu ◽  
Ling Feng Su ◽  
...  

Eco-friendly building materials with perfect thermal insulation & sound absorption property have become intriguing and eye-catching in recent years. In this work, the ultra low-density binderless sandwiching materials were firstly fabricated with ultra low-density of 60-80 kg/m3 by self-designed rapid steam injection technology. The main experimental factor of density, holding time, transmission time, steam injection pressure and fiber’s dimension was respectively investigated to their effects on formation of the new building materials. IR, Py GC-MS and AFM analysis were performed to study the mechanism of binderless sandwiching materials under steam injection process. The bending strength, thermal insulation & sound absorption property of the new materials were also studied. This new building material with no resin use and no formaldehyde release is expected to be reserved as the sandwich for designing thermal insulation & noise reduction building materials.


Author(s):  
Е.Е. УЛЬЯНЧЕНКО

При производстве табачного сырья важную роль играет сокращение продолжительности сушки табачных листьев. Одним из способов интенсификации сушки свежеубранных табачных листьев является прием прорезания средней жилки (ПСЖ) листьев вдоль волокон. По результатам исследований 2019–2020 гг. была создана база данных табачного сырья, полученного при естественном способе сушки с применением приема ПСЖ, которая может служить информационным материалом для производителей табака. Проведена оптимизация процесса сушки табачного листа ПСЖ по показателям качества табачного сырья для расширенного диапазона сортотипов табака. Объектом исследований были сорта отечественной селекции, включенные в Государственный реестр селекционных достижений, допущенные к использованию: Самсун 85, Вирджиния 202, Юбилейный новый 142, Трапезонд 92, Трапезонд 204, Дюбек 33, Американ 287 и Крупнолистный Ильский (находится в стадии государственных испытаний). Критерием оценки эффективности применения приема ПСЖ на исследованных сортах табака являлся совокупный сравнительный анализ следующих показателей контрольных (без ПСЖ листа) и опытных образцов: уровень интенсификации сушки, показатели товарного качества, технологических свойств и химического состава полученного сырья. Установлено, что ПСЖ позволяет интенсифицировать процесс сушки в 1,3–2,46 раза в зависимости от сорта табака и положительно влияет на технологические свойства сырья, у большинства сортов увеличивается выход волокна и сохраняются объемно-упругие свойства. Динамика сушки оказывает влияние на изменение химического состава сырья. В процессе сушки за счет гидролизации солей никотина и его освобождения путем окисления кислородом воздуха уровень никотина в ряде образцов снижается в пределах 10–30%. Чем выше содержание никотина, тем выше крепость табака, грубее его вкус. Изменения углеводно-белкового соотношения в сторону повышения углеводов улучшают вкусовые характеристики сырья. По каждому исследованному сорту не удалось выявить закономерной зависимости его структуры и характера процесса сушки при ПСЖ с преобразованиями химического состава сырья. На основе анализа технологических и качественных показателей табачного сырья, представленных в разработанной базе данных по интенсификации сушки различных сортов табака с применением приема ПСЖ табачных листьев, можно планировать выбор оптимального способа сушки для каждого сорта табака, позволяющего повысить эффективность использования сырья и улучшить его качественные характеристики. In the production of tobacco raw materials, reducing the drying time of tobacco leaves plays an important role. One of the ways to intensify the drying of freshly harvested tobacco leaves is the method of cutting the middle vein (CMV) of the leaves along the fibers. Based on the results of research in 2019–2020, a database of tobacco raw materials obtained by a natural drying method using CMV reception was created, which can serve as information material for tobacco producers. The optimization of the process of drying the CMV tobacco leaf according to the quality indicators of tobacco raw materials for an expanded range of tobacco variety types was carried out. The object of research was the varieties of domestic selection included in the State Register of Breeding Achievements, approved for use: Samsun 85, Virginia 202, Yubileyny novy 142, Trapezond 92, Trapezond 204, Dubek 33, American 287 and Krupnolistnyy Ilskiy (under state testing). The criterion for evaluating the effectiveness of the use of CMV intake on the studied tobacco varieties was a cumulative comparative analysis of the following indicators of control (without CMV sheet) and experimental samples: the level of drying intensification, indicators of commercial quality, technological properties and chemical composition of the obtained raw materials. It is established that CMV allows to intensify the drying process by 1,3–2,46 times, depending on the tobacco variety and has a positive effect on the technological properties of raw materials, most varieties increase the yield of fiber and retain volume-elastic properties. The dynamics of drying affects the change in the chemical composition of raw materials. During the drying process, due to the hydrolysis of nicotine salts and its release by oxidation with air oxygen, the nicotine level in a number of samples decreases within 10–30%. The higher the nicotine content, the higher the strength of tobacco, it is coarser in taste. Changes in the carbohydrate-protein ratio in the direction of increasing carbohydrates improve the taste characteristics of raw materials. For each studied variety, it was not possible to identify a regular dependence of its structure and the nature of the drying process at CMV with transformations of the chemical composition of raw materials. Based on the analysis of technological and qualitative indicators of tobacco raw materials presented in the developed database on the intensification of drying of various varieties of tobacco using the use of CMV of tobacco leaves, it is possible to plan the choice of the optimal drying method for each variety of tobacco, which allows to increase the efficiency of using raw materials and improve its quality characteristics.


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