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.
Dispersion state of fibers in fiber reinforced composites is one of the important factors dominating mechanical properties of them. In this study, we attempt to evaluate the dispersion state via an image analysis. In order to express the dispersion state the degree of dispersion (D(n)) was employed. For the calculation of D(n), a sample image which both sides were 2 N pixel is prepared and divided by grids into segments. Herein, grid size can be 2 i (i=3,4,…,N-1) pixel. After thresholding, the target area is extracted from the sample image and the area ratio in each segment is derived. The degree of dispersion is defined as coefficient of variation between the area ratios. This method was applied for two different cross-section images of carbon fiber (CF) reinforced composites (CFRP). One of them showed a marblelike structure and it was more inhomogeneous than another one. Derived D(n) reflects dispersion state of fibers in the sample images. D(n) of the marblelike sample image was higher than that of more homogenous one with all grid size. Moreover, relationship between D(n) and n showed size of aggregates in the sample images. Therefore D(n) will be a useful parameter to evaluate the dispersion state by the comparing sample images to a reference image.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.