Urea–formaldehyde–propionaldehyde physical gelation resins for improved swelling in water

2006 ◽  
Vol 102 (6) ◽  
pp. 5131-5136 ◽  
Author(s):  
H. R. Mansouri ◽  
A. Pizzi
Keyword(s):  
Urea Formaldehyde ◽  
Physical Gelation

Study of the properties larch and larch wood construction materials

2016 ◽  
Author(s):  
М.А. Чубинский ◽  
К.В. Чаузов
Keyword(s):  
Weight Loss ◽  
Urea Formaldehyde ◽  
Construction Materials ◽  
Siberian Larch ◽  
Larix Sibirica ◽  
Average Weight ◽  
Biological Stability ◽  
Laminated Beam ◽  
Coniophora Puteana ◽  
Larch Wood

Несмотря на огромные запасы, древесина лиственницы до сего времени в незначительных объемах используется в строительной индустрии, других отраслях экономики, что связано как с технологическими сложностями ее переработки, так и недостаточной изученностью ее свойств. Одним из уникальных свойств древесины лиственницы сибирской (Larix sibirica) является ее повышенная естественная биостойкость, наряду с максимально высокой среди отечественных хвойных пород прочностью. Стойкость древесины лиственницы (Larix sibirica) к воздействию дереворазрушающих грибов Coniofora puteana значительно превышает стойкость сосны. В среднем потеря массы ядровой древесины лиственницы сибирской под воздействием дереворазрушающего гриба Coniophora puteana составляет 14,84%, снижаясь с увеличением возраста дерева, а контрольные образцы из ядровой древесины сосны в возрасте 90 лет имели потерю массы 57,8%. Возраст дерева является одним из наиболее значимых факторов, влияющих на степень биостойкости древесины. По мере его увеличения значительно повышается устойчивость деструктивному воздействию дереворазрушающих грибов Coniophora puteana. Положение образцов также влияет на степень биостойкости древесины, однако эта зависимость слабо выражена по сравнению с влиянием возраста и плотности древесины. Исследования кинетики разложения древесины лиственницы сибирской и роли экстрактивных веществ в развитии дереворазрушающих грибов позволяют утверждать наличие связи биостойкости и содержания в древесине экстрактивных веществ. Для изготовления клееного бруса из древесины лиственницы предложена клеевая композиция, включающая карбамидомеламиноформальдегидный клей и карбамидоформальдегидную смолу, модифицированную шунгитами. Ее применение позволяет получать клеевые соединения, не уступающие по прочности при скалывании массивной древесине, как по сухому образцу, так и после его вымачивания. Таким образом, клееный брус из древесины лиственницы сибирской характеризуется высокими показателями биостойкости, прочности и водостойкости. Despite vast reserves, larch wood so far in small volumes used in the construction industry and other sectors of the economy, which is connected as the technological difficulties of its treatment, as well as insufficient knowledge of its properties. One of the unique properties of the wood of Siberian larch (Larix sibirica) is its increased natural biological stability (decay resistant), along with the highest among the domestic softwood strength. Resistance Larch (Larix sibirica) to the effects of wood-destroying fungi Coniofora puteana is much higher than pine. The average weight loss of Siberian larch heartwood exposed wood-destroying fungi Coniophora puteana is 14.84%, decreasing with increasing age of the tree, and control samples of heartwood pine at age 90 had a weight loss of 57.8%. Age of a tree is one of the most significant factors affecting the degree of biological stability of wood. With the increase it significantly increases the stability of the destructive effects of wood-destroying fungi and Coniophora puteana. The position of the sample in tree also affects the degree of biological stability of wood, but this dependence is poorly developed in comparison with the influence of age and wood density. Studies of the kinetics of decomposition of Siberian larch wood and the role of extractives in the development of wood-destroying fungi suggest a link, and the decay resistant of the content in the wood extractives. For the manufacture of larch glued laminated beam proposed adhesive composition comprising urea and melamine-formaldehyde glue and urea-formaldehyde resins, modified shungites. Its use allows to obtain the bonds are not inferior in strength at shearing solid wood as dry sample, and after soaking. Thus, glued laminated beam from Siberian larch wood is characterized by high decay resistant, strength and water resistance.

scholarly journals Effects of Three Biomass Fillers on the Properties of Melamine Modified Urea-Formaldehyde Resin

2020 ◽  
Vol 782 ◽  
pp. 022077
Author(s):  
Shanfeng Xu ◽  
Sanshan Xia ◽  
Yuzhu Chen ◽  
Hui Xiao ◽  
Maoyu Yi ◽  
...  
Keyword(s):  
Urea Formaldehyde ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Modified Urea

scholarly journals Calcium carbonate modified urea–formaldehyde resin adhesive for strength enhanced medium density fiberboard production

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 25010-25017
Author(s):  
Li Lu ◽  
Yan Wang ◽  
Tianhua Li ◽  
Supeng Wang ◽  
Shoulu Yang ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Medium Density ◽  
Ionic Bond ◽  
Resin Adhesive ◽  
Uf Resin ◽  
Modified Urea

Reactions between CaCO3 and CH2O2 during polycondensation of UF resin produce Ca2+. Ionic bond complexation binds Ca2+ with UF resin. The UF resin crystalline percentage decreases from 26.86% to 22.71%. IB strength of resin bonded fiberboard increases from 0.75 to 0.94 MPa.

scholarly journals Potential of Brewer’s Spent Grain as a Potential Replacement of Wood in pMDI, UF or MUF Bonded Particleboard

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 319
Author(s):  
Marius Cătălin Barbu ◽  
Zeno Montecuccoli ◽  
Jakob Förg ◽  
Ulrike Barbeck ◽  
Petr Klímek ◽  
...  
Keyword(s):  
Internal Bond ◽  
Mechanical Performance ◽  
Animal Feed ◽  
Urea Formaldehyde ◽  
Modulus Of Rupture ◽  
Brewer’S Spent Grain ◽  
Beer Brewing ◽  
Removal Of Heavy Metals ◽  
Dry Conditions ◽  
Spent Grain

Brewer’s spent grain (BSG) is the richest by-product (85%) of the beer-brewing industry, that can be upcycled in a plentiful of applications, from animal feed, bioethanol production or for removal of heavy metals from wastewater. The aim of this research is to investigate the mechanical, physical and structural properties of particleboard manufactured with a mixture of wood particles and BSG gradually added/replacement in 10%, 30% and 50%, glued with polymeric diisocyanate (pMDI), urea-formaldehyde (UF) and melamine urea-formaldehyde (MUF) adhesives. The density, internal bond, modulus of rupture, modulus of elasticity, screw withdrawal resistance, thickness swelling and water absorption were tested. Furthermore, scanning electron microscopy anaylsis was carried out to analyze the structure of the panels after the internal bond test. Overall, it was shown that the adding of BSG decreases the mechanical performance of particleboard, due to reduction of the bonding between wood and BSG particles. This decrease has been associated with the structural differences proven by SEM inspection. Interaction of particles with the adhesive is different for boards containing BSG compared to those made from wood. Nevertheless, decrease in the mechanical properties was not critical for particleboards produced with 10% BSG which could be potentially classified as a P2 type, this means application in non-load-bearing panel for interior use in dry conditions, with high dimensional stability and stiffness.

scholarly journals Utilization of Birch Bark as an Eco-Friendly Filler in Urea-Formaldehyde Adhesives for Plywood Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 511
Author(s):  
Roman Réh ◽  
Ľuboš Krišťák ◽  
Ján Sedliačik ◽  
Pavlo Bekhta ◽  
Monika Božiková ◽  
...  
Keyword(s):  
Bending Strength ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Birch Bark ◽  
Gravimetric Analysis ◽  
European Standard ◽  
Scanning Calorimetry ◽  
Wood Processing ◽  
Fagus Sylvatica L ◽  
Positive Effect

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.

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