Study of glycidyl ether as a new kind of modifier for urea‐formaldehyde wood adhesives

Abstract

In this work, the multiepoxy functional glycidyl ether (GE) modified urea-formaldehyde (UF) resins were synthesized via a traditional alkaline-acid process under low formaldehyde/urea (F/U) molar ratio. The synthesized resins were characterized by 13 C magnetic resonance spectroscopy ( 13 C-NMR), indicating that GE can effectively react with UF resins via the ring-opening reaction of epoxy groups. Moreover, the residual epoxy groups of GE could also participate in the curing reaction of UF resins, which was verified by Fourier transform infrared spectroscopy. The storage stability of GE-modified UF resins and the thermal degradation behavior of the synthesized resins were evaluated by using optical microrheology and thermogravimetric analysis, respectively. Meanwhile, the synthesized resins were further employed to prepare the plywood with the veneers glued. For the modification on bonding strength and formaldehyde emission of the plywood, the influences of addition method, type, and amount of GE were systematically investigated. The performance of UF adhesives were remarkably improved by the modification of GE around 20-30% (weight percentage of total urea) in the acidic condensation stage during the resin synthesis.

Effect of a novel environmentally friendly additive of polyaspartic acid on the properties of urea formaldehyde resins/montmorillonite

“…Until now, several methods have been used to improve the properties of UF resins. Except for reducing the formaldehyde/urea molar ratio, addition of formaldehyde‐scavenging agents such as tannin, phenol, melamine, hyperbranched polymers, glycidyl ether, and fluorinated polyether is another effectively way to reduce formaldehyde emission of UF resins. However, these formaldehyde‐scavenging agents have still some drawbacks, such as being environmentally unfriendly, low degradability.…”

Hydrolyzed soy protein isolates modified urea–formaldehyde resins as adhesives and its biodegradability

“…The peak at around 3300 cm −1 is assigned to the stretching vibration of N-H and O-H bonds in the primary amines and hydroxyl groups. [25] It is noticeable that the bands are increased in intensity with the extension of incubation time. The reason was that more and more primary amines and hydroxyl groups exposed as a consequence of the network was broken.…”

The microcapsule-type formaldehyde scavenger: The preparation and the application in urea-formaldehyde adhesives

“…Moreover, the rapid consume of formaldehyde dramatically lowers down the actual F/U of the resin, which usually results in the significant deterioration on bonding performance of the adhesives. Some macromolecular FS have also been reported although their application is still limited, which can reinforce the resin at the same time [31]. We suppose that the design and preparation of a new kind of FS with the reactive agent released in a slow but sustained manner should be an attractive idea and would have potential applications in UF resin related industries.…”

“…In addition, the effect of different reagents of urea and melamine loading in the ethyl cellulose microcapsules was also discussed in this work. The blank UF resin were prepared in the laboratory via the traditional three-step alkaline-acidic-alkaline synthesis process with the F/U molar ratio of 1.05, which has been described in detail in our previous study [31]. The basic properties of the blank resin are listed in Table 1.…”