Application of NIR Reflectance Spectra in Quality Analysis of Epoxy Prepreg
A quick and non destructive method using near infrared(NIR)diffused reflectance spectroscopy was executed to determine the resin content and the volatile content of the epoxy prepreg.Partial least square(PLS) regression algorithm was used to build the calibration models.The optimum models were obtained by selecting different spectral pretreated methods and spectral ranges.The models have determination coefficients(R2) of 97.16 for the resin content and of 95.48 for the volatile content,respectively.The root mean square errors of calibration(RMSEC) are 0.564% and 0.202%,respectively.The root mean square errors of prediction(RMSEP) are 0.617% and 0.274%,respectively.For the predicted set,the paired t test results show that there is no significant difference between the near infrared method and the standard method.The NIR method is satisfied in the quality determination of epoxy prepreg.The results reveal that the NIR spectroscopy can be used as a useful tool for the quality control during the manufacture of prepreg.