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Determination of moisture content of polyamide 66 directly from combination region near‐infrared spectra
Author(s) -
KudaMalwathumullage Chamathca P. S.,
Small Gary W.
Publication year - 2014
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.40645
Subject(s) - polyamide , moisture , water content , calibration , thermogravimetric analysis , materials science , infrared spectroscopy , analytical chemistry (journal) , partial least squares regression , near infrared spectroscopy , spectroscopy , gravimetric analysis , composite material , chemistry , mathematics , chromatography , optics , physics , statistics , geology , organic chemistry , geotechnical engineering , quantum mechanics
The hygroscopic nature of polyamide (PA) polymers motivates the development of analysis tools for use in assessing their moisture content. Among possible analysis techniques, near‐infrared (near‐IR) spectroscopy is non‐destructive, requires little or no sample preparation, and is compatible with sample thicknesses on the order of mm. The work reported here makes use of transmission near‐IR spectroscopy in the combination region (5000–4000 cm −1 ) to develop a protocol for assessing the moisture content of PA 66 samples directly from their spectral intensities after preprocessing with the standard normal variate transform and partial least‐squares. The method is compatible with online or continuous monitoring applications and can be calibrated without the use of destructive reference measurements such as thermogravimetric analysis. The long‐term calibration performance of the technique is evaluated, and on a scale of 0–100% moisture uptake, the standard error of prediction is found to average 1.4% over 6 months. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40645.