IR spectroscopy: Suitable method for determination of curing degree and crosslinking type in melamine–formaldehyde resins

Abstract

Melamine–formaldehyde (MF) resins are widely used as adhesives and finishing materials in the wood industry. During resin cure, either methylene ether or methylene bridges are formed, leading to the formation of a three‐dimensional resin network. Not only the curing degree, but also the chemical species present in the cured resin determine the quality of the final product. Analytical methods allowing a detailed investigation of network formation are of great benefit to manufacturers. In the present work, resin cure of an MF precondensate is studied at different temperatures (100–200 °C) without considering the initial pH as a factor. Isoconversional kinetic analysis based on exothermal curing enthalpies enables calculation of the crosslinking degree at a given time/temperature regime. A semiquantitative determination of the chemical groups present is performed based on solid‐state nuclear magnetic resonance data. Fourier transform infrared spectroscopy has shown to be a fast and reliable analytical tool with high sensitivity toward functional groups and with great potential for at‐line process control. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47691.

Response surface optimization for improving the processing behavior of melamine formaldehyde impregnation resins

“…The absorbance bands were assigned according to Weiss et al 42 The absorbance peak at 815 cm −1 is assigned to the triazine ring. All resin samples show the same intensity of the triazine vibration.…”

“…This explanation also agrees with DSC measurements of the commercially available MF pre‐condensate Kauramin® 773. Kauramin has a very low degree of pre‐condensation and with about 85 Jg −1 it has a significantly higher normalized total curing enthalpy H 42 …”

Preparation of melamine–formaldehyde resin grafted by (3‐aminopropyl) triethoxysilane for high‐performance hydrophobic materials

“…Chemical shifts at 14.75 ppm (δC b ) and 54.55 ppm (δC e ) were assigned to two carbons of ethoxyl group. The peak at 62.65 ppm (δC f ) was belonged to the carbon of methylol which reacted with aminopropyl group [CH 2 NH(CH 2 ) 3 ] . The 13 C NMR results indicated that the CH 2 NHCH 2  groups were generated by the methylol and aminopropyl groups.…”

Biodegradable and antibacterial poly(azomethine‐urethane)‐chitosan hydrogels for potential drug delivery application

“…Melamine, 2,4,6‐triamino‐1,3,5‐triazine, is a nitrogen‐rich organic compound and it has been widely used different applications such as textile, plastic, paint, flame retardant, paper coating, laminates, fertilizer, biosensor, and detection of heavy metal ions …”

“…19,20 Melamine, 2,4,6-triamino-1,3,5-triazine, is a nitrogen-rich organic compound 21 and it has been widely used different applications such as textile, plastic, paint, flame retardant, paper coating, laminates, fertilizer, biosensor, and detection of heavy metal ions. [22][23][24] In this work, biodegradable and antibacterial poly(azomethine-urethane) (PAMU)-and CS-based hydrogels have been fabricated by using CS for the controlled drug release application. Also, hydrophobicity, water uptake, in vitro biodegradation, protein absorption, antibacterial activity, and drug loading or release capacity have been evaluated to investigate the usability as biomaterials of the fabricated hydrogels.…”