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

Abstract

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.

Development and characterization of a recycled nylon fiber reinforced and nano-fly ash hybridized high impact performance polypropylene composite for sustainability

“…In another study, polydopamine and anhydrous copper sulfate treated aramid fiber was used to reinforce epoxy matrix separately. 58,59 Both the authors reported increased interfacial adhesion and enhanced mechanical properties of the composites due to the complexation (coordination bond) on the fiber surface. In this work, additional coating of NF with APTES promoted the surface activity, exposed area and interaction of the free NH 2 group of the APTES with the MA group of the BM and establishment of the amide linkage between fiber and BM.…”

CuSO4 nanoparticles loaded onto poly (toluenesulfonic acid‐formaldehyde)/polyethyleneimine composites: An efficient retrievable catalyst for A3/decarboxylative A3 reactions

“…As shown in Figure 2, the stretching peak at 3,427 cm −1 together with bending peak at 1,454 cm −1 (curve a) is attributed to characteristic N–H. [ 36,38,39 ] When CuSO 4 immobilized on PTSAF, the electron cloud density of the nitrogen atoms on PEI of the PEI/PTSAF decreases, and the N–H absorption peaks move to lower wave number from 1,454 to 1,443 cm −1 (curve b), respectively.…”

“…PEI is an amorphous, water‐miscible branched polymer with repeating units of primary, secondary, and tertiary amine moieties. [ 35,36 ] The PEI plays as a strong donor of electron pair and thus effectively enhances the electron density at the center of transit metal and thus accelerate the catalysis. Poly (toluenesulfonic acid‐formaldehyde) (PTSAF) is a novel water‐immiscible strong acidic resin synthesized by the copolymerization of p ‐toluenesulfonic acid and paraformaldehyde in the presence of catalytic amount of sulfuric acid.…”

Sulfone-functionalized poly(p-phenylene terephthalamide) copolymer fibers with improved interfacial adhesion to epoxy matrices

“…To improve the adhesion of fiber-reinforced composites, chemical treatments, and physical modification of aramid fibers were applied, such as plasma treatment, 16–19 surface coating 20–23 and grafting. 24–28 After modification, the polarity and the roughness of the fiber increased, leading to the excellent interfacial properties of the aramid fiber-reinforced composites. However, the roughening of the fiber surface will degrade its mechanical properties and the long-term processing is not conducive to industrial production.…”