Studying the physio-chemical and thermal properties of melamine-formaldehyde resin modified with caprolactam and ethylene glycol

Document Type : Research Paper

Authors

1 Department of Science and Wood and Paper Industries, Faculty of Natural Resources, University of Tehran, Karaj, Iran.

2 Faculty of Chemistry, University of Tehran, Tehran, Iran.

3 Department of Wood and Forest Technology, University of Linnaeus, Sweden.

10.22059/jfwp.2023.358076.1250

Abstract

Melamine-formaldehyde (MF) resin is commonly used in coating and casting mold production because of its favorable physical and thermal characteristics. However, its use is restricted due to formaldehyde release, short shelf life, and high fragility. A variety of substances like lactams and alcohols have been employed to enhance MF resin properties. This study attempts to improve MF resin's characteristics by including ethylene glycol and caprolactam as plasticizers in resin formulation to reduce free formaldehyde content and prolong its shelf life. Two different molar ratios of melamine to formaldehyde (1.6 and 1.5 mol) were used in the synthesis of the MF resin, with the inclusion of plasticizers: caprolactam and ethylene glycol. The physical characteristics such as viscosity, density, and gelling time, chemical attributes (Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR)), and thermal properties (thermogravimetric analysis (TGA)) of MF resins were examined. The results showed that the addition of ethylene glycol and caprolactam increased curing time, density, solids content, and shelf life while reducing free formaldehyde content. While the individual application of either plasticizer had no significant effect on gelation time, their simultaneous use increased it. FTIR and 1H-NMR confirmed the presence of the plasticizers in the MF resin's chemical structure, while TGA demonstrated that the addition of plasticizers leads to an increase in its thermal stability. However, the amount of resin residue after TGA analysis was different according to the type of plasticizer.

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References

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Forest and Wood Products
Volume 76, Issue 2
September 2023
Pages 141-151

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