The Determination of Quantity of Unreacted Components in In-situ Polymerized Carbon Fiber Reinforced Polyamide 6 Composites

The quantity of low-molecular weight components included in carbon fiber reinforced in-situ polymerized polyamide 6 (iPA6-CFRP) was estimated from molecular weight distribution measured by gel permeation chromatography (GPC). Although it obtained by the weight variation of the composites across the removal of the target components, precision of the measurements depends on the weight of themselves. By contrast, GPC allows us to apply to a small quantity of sample. Moreover, we can determine the quantity without the removing and subsequent drying process. The calibration curve for the determination derived from relation between the weight fractions of the target (ε-caprolactam) included in known samples and the area ratio calculated from the molecular weight distribution of those acquired by GPC. We applied the curve to iPA6-CFRP and measured temporal changes of the quantity of the components on the removing process. The reliability of the measurements was confirmed by comparison with those determined by the weight variation. As an example of application of the method, we measured concentration distribution of the target in thickness direction of iPA6-CFRP before and after the hot water extraction. From the variation of the distribution, the mass transfer phenomena will be express by unsteady-state one-dimensional diffusion. unreacted components, Carbon fiber reinforced composites, In-situ polymerized polyamide 6, GPC