NIRS Determination of Hydroxyl Value of PET

A method of NIRS for the determination of hydroxyl value of hydroxyl-terminated ethylene oxide and tetrahydrofuran copolymer (PET) was proposed. Based on the spectral data of PET and by the application of principal component regression (PCR) and partial least square (PLS), a calibration model relating the hydroxyl value of PET to the respective NIR spectra was established. It was found that the results obtained by the present method were in consistency with those obtained by the chemical method. The relative error of results of hydroxyl value obtained by NIRS was within 5%. Error of prediction of the calibration model was reduced by selecting part of wavelengths by the genetic algorithm (GA).