Use of Near-Infrared Spectroscopy for On-Line Monitoring the Quality of Prepreg Cloth

Abstract

On-line monitoring the prepreg quality in the polymer composite industry continues to be a major emphasis, it will reduce the amount of prepreg manufactured under "outside specifications". A near-infrared spectroscopy has been implemented for measurement of resin content, pre-curing degree of resin and volatile content during the manufacture of glass/phenolic resin prepreg cloth. The regression method employed was partial least squares (PLS). The optimum models were obtained by selecting different spectral pretreatments and spectral ranges. The determination coefficients (R 2) for the resin content, pre-curing degree and volatile content were 98.36, 98.76 and 98.33, respectively. The root mean squares of cross-validation (RMSECV) were 0.364, 0.145 and 0.182 respectively for the resin content, pre-curing degree and volatile content, respectively. The NIR method was applied to monitor the quality of prepreg cloth on line. The results showed that the monitored values were closed to the actual values. The study indicates that the on-line quality analysis of prepreg cloth was realised by using NIR technique.

Near Infrared-spectroscopy in resin transfer molding – determination of the degree of cure

“…Today, the suitability of NIR spectroscopy for inline process monitoring is mainly investigated for prepreg production via the solvent route. Starting before impregnation, the sizing content on the bers[16] and later in the process matrix-related parameters such as the resin content [16][17][18][19][20][21][22][23], volatile content [16][17][18][19][20][21][22][23], soluble resin content [16][17][18]21], the gel time [24], initiator content [25] and the ash content [26] have been determined for various textile and resin combinations. The quality of prepregs can also be determined during storage by NIR spectroscopy [27] in order to avoid the use of expired material.…”

A Dynamic Calibration Method of Broad Band Infrared On-line Measurement System

“…It is now getting more and more broadly used in many domains, such as, chemical industry, environment, agriculture, medicine [1][2][3][4][5][6] for its high measurement speed, nonpollution, non-contact and non-damage.In order to eliminate bad influences of environment, double-wavelength contrast method [7][8][9] is adopted. That is choose one wavelength of which infrared ray attenuate strongly when it passes through determinand, and choose the other wavelength of which infrared ray does no attenuate almost.…”