Infrared spectrometric examination of paper.  II.  Determination of urea-formaldehyde resin

Wise, John K.; Smith, Clara D.

doi:10.1021/ac50157a029

Cited by 6 publications

(1 citation statement)

References 3 publications

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“…The production of the urea‐formaldehyde adhesives involves several steps, with the first being the addition of the formaldehyde to the urea under neutral or basic conditions,1 which can be followed by infrared spectroscopy. MIR spectroscopy was already used in 1967 to determine the UF resin content in paper,23 to study the prepolymer and cured state,24 the curing reactions,25 to identify and follow the appearance, increase, decrease, and disappearance of several of the main chemical groups during the preparation of the initial UF phase of the reaction and the subsequent reaction of melamine with the UF resin that was formed 26. Moreover, it was used to investigate the structure development of UF resins in a synthesis process, and to reveal structural differences of reaction inter‐products of urea and formaldehyde that were observed in alkaline and acidic media and at different F/U molar ratios 27.…”

Section: Introductionmentioning

confidence: 99%

Assessment of resin formulations and determination of the formaldehyde to urea molar ratio by near‐ and mid‐infrared spectroscopy and multivariate data analysis

Costa¹,

Amaral²,

Alvim³

et al. 2012

J of Applied Polymer Sci

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The molar ratios of formaldehyde (F) to urea (U) of three resin formulations in the range from 0.90 to 1.49 have been analyzed by means of Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Fourier Transform-Near-Infrared (FT-NIR) spectroscopy. Application of Principal Component Analysis (PCA) to the spectra (MIR and NIR) allowed to separate them according to the molar ratio and to distinguish between two groups of resins. Soft Independent Modeling of Class Analogy (SIMCA) allowed classification of new resin samples with high model distances between the classes. Partial Least Squares Regression (PLS-R) models based on MIR (NIR) spectra resulted in high coefficients of determination (R 2 ) values, low errors, and high residual prediction deviations (RPD). To confirm the reproducibility of the process and to carefully evaluate twice all multivariate analysis results obtained, different batches of resins have been prepared to have an additional independent sample set. The number of samples required for MIR and possible applications of MIR and NIR spectroscopy in this context including limitations have been discussed.

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