Surface ammonification of the mutual-irradiated aramid fibers in 1,4-dichlorobutane for improving interfacial properties with epoxy resin

Preparation of aramid-based epoxy resin from low-grade aramid

Low-grade aramid fibers, an unavoidable by-product in the industrialized process of aramid fiber production, are difficult to utilize and harmful to the environment. In this study, low-grade aramid fibers were recycled to assemble a high-quality epoxy resin through an epoxidation modification. Triggered by the epichlorohydrin, the molecular configuration of the low-grade aramid fibers was altered through crosslinking and chain-extension processes. bisphenol-A epoxy resin (E-51) with 5% aramid-based epoxy resin cured product exhibited improved mechanical and thermal properties, outperforming pure E-51 and pure aramid. This improvement is caused by the increased percentage of epoxide groups and flexible ether bonds. This work opens up new possibilities to maximize the reclamation of low-grade aramid fibers, which currently poses an obstacle in waste recycling.

Low-grade aramid fibers are transformed to high value-added aramid-based epoxy resin. Bisphenol-A epoxy resin with aramid-based epoxy resin cured products exhibited improved mechanical properties, outperforming pure E-51 and pure aramid.

Development in Additive Methods in Aramid Fiber Surface Modification to Increase Fiber-Matrix Adhesion: A Review

This review article highlights and summarizes the recent developments in the field of surface modification methods for aramid fibers. Special focus is on methods that create a multifunctional fiber surface by incorporating nanostructures and enabling mechanical interlocking. To give a complete picture of adhesion promotion with aramids, the specific questions related to the challenges in aramid-matrix bonding are also shortly presented. The main discussion of the surface modification approaches is divided into sections according to how material is added to the fiber surface; (1) coating, (2) grafting and (3) growing. To provide a comprehensive view of the most recent developments in the field, other methods with similar outcomes, are also shortly reviewed. To conclude, future trends and insights are discussed.

Cu (II) coordination modification of aramid fiber and effect on interfacial adhesion of composites

In this article, active groups were introduced to the surface of aramid fiber by building a Cu2+ bridge between the aramid fiber and polyethyleneimine (PEI) to improve adhesion in composites between the aramid fiber and the matrix such as epoxy resin. The changes in the structure and properties of the aramid fiber were verified with Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and the single-fiber pull-out test. The FTIR and XPS results show a significant change in the structure and morphology of the aramid fiber after modification. The results of the single-fiber pull-out test show that the interfacial shear strength (IFSS) of epoxy composites reinforced with PEI-grafted aramid fiber increases by 48.8% compared with the IFSS of epoxy composites reinforced with untreated fiber. Thus, the proposed method can improve the interfacial bonding of composites by creating a copper ion bridge between the aramid fiber and PEI.