Improve the interfacial properties of carbon fiber reinforced epoxy resin composites by maleimide‐modified waterborne polyurethane sizing agent

Abstract

The N‐(4‐hydroxyphenyl) maleimide (4‐HPM) modified waterborne polyurethane emulsions (MWPU) were used as surface sizing agents to improve the interfacial adhesion between carbon fibers (CF) and epoxy resin matrix. Dynamic light scattering (DLS), transmission electron microscope (TEM), and thermogravimetric analysis (TGA) showed the particle size distribution, storage stability, and thermal stability of the modified MWPU. And the surface reactivity of CF increased significantly after sizing. The interfacial shear strength (IFSS) and the interlaminar shear strength (ILSS) of CFREs were tested, and the fracture morphology was observed. The result showed that a continuous and uniform sizing layer is formed on the surface of CF. In particular, the comprehensive performance and interfacial modification effect of the MWPU emulsion outperformed other samples when the 4‐HPM content was 1.0 wt%. Compared with unsized carbon fibers, the IFSS and ILSS are up to 71.30% and 30.81% higher, respectively.

A novel method for the synthesis of solvent‐free and high‐solid‐content waterborne polyurethanes by introducing a small amount of polyethylene glycol

“…This leads to the formation of a thick hydrophilic layer, ultimately resulting in an overall increase in the viscosity of the dispersion. [39][40][41] The intermolecular interaction among micelles is illustrated schematically in Figure 3.…”

Optimization of mode‐I fracture toughness using the Taguchi method in cellulosic fiber‐Grewia Optiva reinforced biocomposites

“…54 Rectangular specimens of 150 mm × 20 mm × 5 mm were cut and loaded utilizing a three-point loading system to undergo bending, keeping the span-to-depth ratio as 16:1, as shown in Figure 3b. The flexural stress, flexural strain, and flexural modulus are calculated using Equations (3)- (5).…”

“…Yao et al 4 have used the one-step Chemical Vapor Deposition (CVD) technology to deposit carbon nanotubes on the carbon fiber surface before fabricating composites by molding technology and found improved stress transfer between the carbon fibers and surrounding epoxy matrix which resulted in improved mechanical properties of composites as well as their dielectric properties. Recently, Li et al 5 claimed that the interfacial adhesion of carbon fiber and epoxy matrix significantly increased after using maleimide-modified waterborne polyurethane as sizing agent. These studies reveal that fiber treatment, matrix modification, and fabrication method play a major role in strength enhancement.…”

“…Grewia Optiva fiber has the potential of being used as a reinforcing biodegradable material like other natural fibers. Several studies using natural fibers such as date palm, 2 jute, 3 oil palm, 4 sisal, 5 kenaf, 6 and flax 7 as reinforcing material can be found in the literature. The effect of fiber modification, hybridization, processability, and so forth, on the mechanical strength and wear rate is also reported by many researchers in the past.…”