ESTIMATING THE DEGREE OF MERCERIZATION USING NEAR-INFRARED SPECTROSCOPY

A consistent degree of mercerization is very often a necessary prerequisite in cotton fabric preparation prior to dyeing. A rapid method of measuring the degree of mercerization was developed by use of a near-IR diffuse reflectance technique which does not require any sample preparation. It is shown in the x-ray diffraction study that the modification of the cellulose crystal lattice occurs during mercerization due to the conversion of cellulose I to cellulose II. This morphological change in the cellulose probably affects the O-H group which is involved in hydrogen bonding in the cellulose chain. The near-IR spectra of the cotton cellulose exhibited a noticeable modification in the O-H stretching first overtone band as a consequence of mercerization, A predictive model regression equation, which includes the wavelength at 1445 nm, has been developed. The near-IR instrument-determined mercerization indices showed an excellent correlation with the barium activity number when r(2) was equal to 0.98.