NIR Applications for Measuring Water Sorption and Vinyl Unsaturation in Dental Dimethacrylate Polymers

Published

April 1, 2001

Author(s)

Sabine H. Dickens, J W. Stansbury, C J. Floyd

Abstract

Integrated near infrared (NIR) absorbance has been used to determine the absorptivity of the [nu]₂+[nu]₃ combination band of water in several organic solvents so that water sorption in materials can be estimated from NIR spectra. To establish the applicability of this technique to dental polymers, weight changes due to water sorption were correlated to the changes in the integrated NIR absorbance of H₂O in the polymers. The straight line fit was found to be (319 15) L mol^-1 cm1 and the correlation coefficient R² estimated from 84 data points is 0.994. The NIR measurement of conversion in dental resins followed the decrease of the integrated absorbance of the first overtone of the =CH stretch. For the latter, sensitivity of the NIR technique was superior to those based on the mid-IR. Conversion values measured by NIR and by mid-IR techniques did not differ significantly, but the NIR method was more sensitive. These nondestructive NIR analyses offer convenience, practical sample dimensions and precision.

Citation

Polymer Preprints

Volume

42

Issue

no. 1

Pub Type

Journals

Keywords

degree of cure, dental monomers, dimethacrylate resins, hydrogen bonding, NIR spectroscopy, water sorption

Citation

Dickens, S. , Stansbury, J. and Floyd, C. (2001), NIR Applications for Measuring Water Sorption and Vinyl Unsaturation in Dental Dimethacrylate Polymers, Polymer Preprints (Accessed July 13, 2026)

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