Analysis method for rapidly measuring free isocyanate (NCO) in polyurethane

Abstract

The invention relates to an analysis method for rapidly measuring free isocyanate (NCO) in polyurethane, relating to a non-contact analysis method for quantifying NCO through combining a Raman spectroscopy and partial least squares (PLS). The analysis method comprises the following steps of: acquiring Raman spectrum atlases of polyurethane samples with different NCO contents through a Raman fiber optical spectrometer; selecting a modeling sample, modeling and optimizing through the PLS by taking Raman spectrum data of the modeling sample as an independent variable and the NCO measured value of the sample as a dependent variable, and establishing an NCO Raman prediction model; and measuring the NCO content in the measured sample by using the established model. When used for NCO quantitative analysis, no any pretreatment for the polyurethane sample is needed, lossless, accurate, mass and rapid detection can be realized, and the defects of pretreatment complexity and time waste of the traditional analysis method are overcome; and the analysis method is suitable for process control and analysis detection in polyurethane production.

Description

technical field [0001] The present invention relates to a method for measuring the content of free-NCO by Raman spectroscopy, especially provides a method based on the Raman characteristic spectrum intensity of polyurethane reactants, using PLS to establish a prediction model, and detecting the content of free-NCO in polyurethane through the prediction model. Method for detecting free-NCO content. Background technique [0002] At present, the determination of the content of free isocyanate groups mainly includes chemical analysis, potentiometric titration, infrared spectroscopy, spectrophotometry and chromatography. [0003] Chemical analysis is a method commonly used at home and abroad, but it needs to be completed in a laboratory, and the detection time is 40-60 minutes. The potentiometric titration method uses the potentiometric method to indicate the titration end point, and the operation is cumbersome and takes a long time. Chromatography is a commonly used method for...

AI Technical Summary

Problems solved by technology

The potentiometric titration method uses the potentiometric method to indicate the titration end point, the operation is cumbersome and the time is long

Chromatography is a commonly used method for the determination of isocyanate, but the investment cost of equipment is high, and the pretreatment is also troublesome

The determination of spectrophotometry requires the sample to be derivatized before determination, and the operation is relatively cumbersome

Infrared spectroscopy using isocyanate groups at infrared 2272cm -1 It is a very effective method with simple operation and high sensitivity, and can be used to track the whole process of chemical reactions, but it also needs to be completed in the laboratory, and the equipment requirements are high

Images