Low Mole Ratio UF and UMF Resins Entailing Uron-Type Methylene-Ether Groups and their Low Formaldehyde Emission Potentials

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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Modification of Oxidized Starch Polymer with Nanoclay for Enhanced Adhesion and Free Formaldehyde Emission of Plywood

Journal of Polymers and the Environment ◽

10.1007/s10924-021-02101-w ◽

2021 ◽

Author(s):

Muhammad Adly Rahandi Lubis ◽

Sumit Manohar Yadav ◽

Byung-Dae Park

Keyword(s):

Formaldehyde Emission ◽

Oxidized Starch

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Improved strength properties of LVL glued using PVAc adhesives with physical treatment-based Rubberwood (Hevea brasiliensis)

Open Agriculture ◽

10.1515/opag-2020-0072 ◽

2020 ◽

Vol 5 (1) ◽

pp. 711-725

Author(s):

Sutrisno ◽

Eka Mulya Alamsyah ◽

Ginanjar Gumilar ◽

Takashi Tanaka ◽

Masaaki Yamada

Keyword(s):

Shear Strength ◽

Hevea Brasiliensis ◽

Formaldehyde Emission ◽

Strength Properties ◽

Modulus Of Rupture ◽

Horizontal Shear ◽

Physical Treatment ◽

Cold Pressing ◽

Laminated Veneer Lumber ◽

Pressing Time

AbstractThe properties of the laminated veneer lumber (LVL) composed of the boiled veneer of Rubberwood (Hevea brasiliensis) using polyvinyl acetate (PVAc) adhesives in various cold-pressing time and various conditioned time with loaded and unloaded were studied. Five-ply LVL was produced by boiling veneer at 100°C for 90 min as pretreatment and cold-pressing time at 12 kgf cm−2 for 1.5, 6, 18, and 24 h then conditioned at 20°C and 65% relative humidity (RH) with loaded (12 kgf cm−2) and unloaded for 7 days as physical treatment. Especially for the delamination test, the specimens were immersed at 70 ± 3°C for 2 h and dried in the oven at 60 ± 3°C for 24 h; then, the specimens were solidified at room temperature (20°C and 65% RH) with loaded (12 kgf cm−2) and unloaded for 7, 10, 12, and 14 days. To determine the performance of LVL, the density, moisture content (MC), delamination, modulus of elasticity (MOE), modulus of rupture (MOR), horizontal shear strength, and formaldehyde emission tests were conducted according to the Japanese Agricultural Standard (JAS 2008) for structural LVL. The MOE and MOR values were significantly influenced by the physical treatment, however, neither to horizontal shear strength nor to formaldehyde emission. The best performance of LVL has resulted from unloaded LVL with cold-pressed time for 18 h; the MOE and MOR values were 9,345.05 ± 141.61 N mm−2 and 80.67 ± 1.77 N mm−2, respectively. The best value of the horizontal shear strength was obtained from the LVL with 18 h cold-pressing time and conditioned with loaded (13.10 ± 1.47 N mm−2) and unloaded (12.23 ± 1.36 N mm−2). The percentage of delamination values decreased with an increase in the cold-pressing time and conditioning time. The lowest value of delamination (19.06%) was obtained from the LVL with 24 h cold-pressing time and conditioned with loaded for 14 days. Except the delamination test, all other properties fulfilled the JAS.

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“Direct Dripping”: A High-Temperature, High-Formaldehyde Emission Electronic Cigarette Use Method

Nicotine & Tobacco Research ◽

10.1093/ntr/ntv080 ◽

2016 ◽

Vol 18 (4) ◽

pp. 453-459 ◽

Cited By ~ 75

Author(s):

Soha Talih ◽

Zainab Balhas ◽

Rola Salman ◽

Nareg Karaoghlanian ◽

Alan Shihadeh

Keyword(s):

High Temperature ◽

Formaldehyde Emission ◽

Electronic Cigarette ◽

Cigarette Use

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Influence of temperature on formaldehyde emission parameters of solvent-based coatings

Journal of Coatings Technology and Research ◽

10.1007/s11998-020-00432-2 ◽

2021 ◽

Author(s):

Yaoyao Tan ◽

Yatao Zhi ◽

Meiping Gao ◽

Zhanjun Cheng ◽

Beibei Yan ◽

...

Keyword(s):

Formaldehyde Emission ◽

Influence Of Temperature ◽

Influence Of Temperature On

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Physico-mechanical properties of plywood bonded with ecological adhesives from Acacia mollissima tannins and lignosulfonates

The European Physical Journal Applied Physics ◽

10.1051/epjap/2017170067 ◽

2017 ◽

Vol 78 (3) ◽

pp. 34813 ◽

Cited By ~ 6

Author(s):

Naima Rhazi ◽

Mina Oumam ◽

Abdessadek Sesbou ◽

Hassan Hannache ◽

Fatima Charrier-El Bouhtoury

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Phenol Formaldehyde ◽

Waste Product ◽

Formaldehyde Emission ◽

Extraction Methods ◽

Press Temperature ◽

Pulp Industry ◽

Pressing Time ◽

Chemical Conditions

The objective of this research was to develop ecological adhesives for bonding plywood panels using lignosulfonates, a common waste product of the wood pulp industry, and natural tannin extracted from Moroccan bark of Acacia mollissima using different process. Natural tannin and lignin were used in wood adhesives formulation to substitute resins based on phenol and formaldehyde. To achieve this, the lignosulfonates were glyoxalated to enhance their reactivity and the used tannins obtained by three different extraction methods were compared with commercial mimosa tannin. The proportion of Acacia mollissima tannins and lignosulfonates, the pressing time, the pressing temperature, and the pressure used were studied to improve mechanical properties, and bonding quality of plywood panel. The properties of plywood panels produced with these adhesives were tested in accordance with normative tests. Thus, the tensile strength, and the shear strength were measured. The results showed that the performance of the plywood panels made using biobased tannin adhesives was influenced by physical conditions such as pressure, press temperature as well as by chemical conditions, such as the tannin-lignin ratio. It exhibited excellent mechanical properties comparable to commercially available phenol-formaldehyde plywood adhesives. This study showed that biobased adhesives formulations presented good and higher mechanical performance and no formaldehyde emission.

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