NIR spectroscopy: A useful tool for quality control of glass/phenolic prepreg manufacture

Quality control of prepreg during production is a major emphasis in the polymer composite industry. A technique to control the quality of glass/phenolic prepreg cloth by near-infrared (NIR) spectroscopy has been successfully developed. Calibration models for the resin content, volatile content, and degree of pre-cure of the resin were created respectively by performing partial least square regression. Several spectral pretreatments were tested to obtain the optimum models. NIR prediction results showed good correlation with those from the standard method. After validation, the method was applied in the product line to investigate the relationship between these three factors and various processing parameters. Using the on-line monitoring results, quality control was realised by adjusting the appropriate processing parameters.