Determination of ash content in silicon dioxide filled epoxy-phenolic prepreg using near infrared spectroscopy

This paper presents an application of near infrared spectroscopy associated with partial least squares regression calibration, for ash content analysis of prepreg in the manufacturing progress of copper clad laminate for printed circuited boards. The performance of the model was assessed by cross validation and external validation. The correlation coefficient and the root mean squared error of calibration and validation were 0.99, 0.25% and 0.98, 0.34%, and the measurement process was accomplished in less than 2 min compared to over 60 min for traditional thermo gravimetric analyzsis. The paired t-test results revealed that there was no significant difference between the two methods.