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

Oxidized starch (OS) adhesives with a balance between their adhesion and disintegration properties were prepared by controlling the degree of oxidation and modifying the cross-linker type and level to replace urea-formaldehyde (UF) resins for easy recycling of medium density fiberboard (MDF). Four molar ratios of H2O2/starch, two types of cross-linker, i.e., blocked-pMDI (B-pMDI) and citric acid (CA), and three levels of the cross-linkers were employed to tailor the performance of the OS adhesives. The OS reacted with the isocyanate groups from the B-pMDI to form amide linkages, while it formed ester linkages by reacting with the CA. The resulting B-pMDI/OS-bonded MDF had better physical and mechanical properties than the CA/OS-bonded MDF, with comparable adhesion (0.34 MPa) to UF resins and ten times greater degree of fiber disintegration than UF resins. The combination of a 0.5 molar ratio OS with 7.5 wt% of B-pMDI produced MDF exhibiting an optimal balance between adhesion and disintegration, suggesting that such OS adhesives could someday replace UF resins in manufacturing and recycling of MDF without formaldehyde emission.

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Study on Modification of UFRA by Enzyme Hydrolysis Prepared Oxidized Starch

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.268-270.574 ◽

2012 ◽

Vol 268-270 ◽

pp. 574-579

Author(s):

Rui Hang Lin ◽

Xiao Bo Wang ◽

Xiao Feng Zhu ◽

Zhen Zhong Gao

Keyword(s):

Enzymatic Hydrolysis ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Urea Formaldehyde Resin ◽

Enzyme Hydrolysis ◽

Curing Temperature ◽

Impact Factors ◽

Formaldehyde Resin ◽

Oxidized Starch ◽

Modified Urea

In this work, we concentrate on the preparation of oxidized starch modification reagent by enzymatic hydrolysis pretreatment, preparation of the urea-formaldehyde resin with low toxicity. The performance of modified urea-formaldehyde resin depend on the oxidation degree of oxidized starch and whether using enzymatic hydrolysis pretreatment or not. 100-PH9-HOS(the starch enzymatic hydrolysis then oxidized in 100°C with pH 9) synthetized modified urea-formaldehyde resin (100-PH9-HOS-UF) only with a free formaldehyde content of 0.14%, the lowest formaldehyde emission of 0.6078mg/L. Infrared spectroscopy test results show that samples at 3350cm-1 p-hydroxyl hydrogen bonds of association half-peak width minimum hefeng, amino-hydroxy hydrogen bond of association that samples are the weakest and with maximum cross-linking degrees; The modified urea-formaldehyde resin by oxidized starch curing properties of impact factors show that: the deeper drgree of oxidation, the higher curing temperature and the lower enthalpy.

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4. Formaldehyde Emission Rates from Dissecting Tables in a Gross Anatomy Laboratory

10.3320/1.2763807 ◽

2000 ◽

Author(s):

C. Keil ◽

F. Akbar-Khanzadeh ◽

K. Konecny

Keyword(s):

Gross Anatomy ◽

Formaldehyde Emission ◽

Emission Rates ◽

Anatomy Laboratory

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RESEARCH STUDIES CONCERNING THE FORMALDEHYDE EMISSION OF PLYWOOD USING THE FLASK METHOD

Environmental Engineering and Management Journal ◽

10.30638/eemj.2006.044 ◽

2006 ◽

Vol 5 (4) ◽

pp. 569-580

Author(s):

Valeriu Petrovici ◽

Simona Nicoleta Urdea ◽

Judith Kinga David ◽

Oana-Andreea Pirnuta

Keyword(s):

Formaldehyde Emission ◽

Research Studies

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Formaldehyde emission, combustion behavior, and artificial weathering characteristics of electrostatic powder coated wood composite panels

Wood Material Science and Engineering ◽

10.1080/17480272.2021.1901142 ◽

2021 ◽

pp. 1-11

Author(s):

Memiş Akkuş ◽

Turgay Akbulut ◽

Zeki Candan

Keyword(s):

Formaldehyde Emission ◽

Composite Panels ◽

Wood Composite ◽

Artificial Weathering ◽

Combustion Behavior

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

Polymers ◽

10.3390/polym13040511 ◽

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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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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