Introducing flexibility in urea–formaldehyde resins: Copolymerization with polyetheramines

Abstract

Adhesives obtained by copolymerizing urea, formaldehyde, and difunctional polyetheramine with different molecular weights (230, 600, 900, and 2000 g mol−1) are presented as a more resilient alternative to conventional urea–formaldehyde resins. Urea and polyetheramine contents were varied and the resulting resins characterized by FTIR, 13C‐NMR, and TGA. These resins were used for production of agglomerated cork panels, an application that demands that the binder system is flexible. Polyetheramine with molecular weight 900 g mol−1 yielded the most promising agglomerated cork panel, with remarkable flexibility, good tensile strength, and with the E1 formaldehyde content specification for wood‐based panels used in construction, according to European Standard EN 12460‐5. These new thermoset adhesives have demonstrated to be capable of being used in systems where conventional formaldehyde‐based resins do not perform well due to inherent high rigidity. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1834–1843

Co-Condensation of Phloroglucinol-Nonylphenol-Urea-Formaldehyde Resin Enables High Toughness and Enhanced Warpage Resistance

“…1,3,5-Trihydroxybenzene and 2-nonylphenol were introduced into the UF resin synthesis system to prepare phloroglucinolnonylphenol-urea-formaldehyde (P-NP-UF) co-condensed resin. The results of FTIR and 13 C NMR analysis showed that benzene ring and long-chain alkyl structure were successfully introduced into the molecular structure. Compared with UF resin, the peak curing temperature (T p ) of cocondensed resin moved to a lower temperature and the apparent activation energy decreased.…”

“…The spectral resolution was 4 cm −1 , and the scanning rate was 20 min −1 . Solid-state 13 C NMR analysis of P-NP-UF resin was performed on a Bruker Avance III spectrometer (Switzerland). The curing kinetics of the resin was measured by using Netzsch 204 differential scanning calorimeters (Germany).…”

“…The solid-state 13 C NMR spectra of UF, P-UF, NP-UF, and P-NP-UF resin are presented in Figure 2d,e. For the UF resin, the chemical shift at 159.9 ppm was assigned to the carbonyl carbon (C�O) of urea and its derivatives.…”

Highly Branched Polyurea-Enhanced Urea-Formaldehyde Resin

“…How to balance the formaldehyde emission and performance? In recent years, modifications of UF and MUF resins with linear 26,27 and hyperbranched polymers have been reported. Especially modifications with poly(amidoamine)s with different end groups such as −NH 2 (aliphatic), −OH (aliphatic), −CHO, and −COO− were intensively studied in the literature.…”

“…How to balance the formaldehyde emission and performance? In recent years, modifications of UF and MUF resins with linear , and hyperbranched polymers have been reported. Especially modifications with poly­(amidoamine)­s with different end groups such as −NH 2 (aliphatic), −OH (aliphatic), −CHO, and −COO– were intensively studied in the literature. − Highly branched structure and high functionality of the involved polymers resulted in improved bonding performance, durability, storage stability, and reduced formaldehyde emission level.…”