To improve the dispersion of graphene oxide (GO) nanosheets in sizing agent and to enhance the interfacial adhesion between GO and epoxy, GO nanosheets were chemically modified with cyanuric chloride (TCT) and diethylenetriamine (DETA). The functionalized GO (i.e. GO-TCT-DETA) with different contents was introduced into the carbon fiber (CF) interface by sizing process. The uniform distribution of GO sheets on CF surface and the enhancement of surface roughness were obtained. Moreover, significant enhancements (i.e., 104.2%, 100.2%, and 78.3%) of interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and flexural properties were achieved in the composites with only 1.0 wt% GO-TCT-DETA sheets introduced in the fiber sizing. The GO-TCT-DETA in the interface region enhanced the stress being transferred effectively and the local stress concentrations being relieved. This study indicates that the utilization of functionalized GO is one of the alternative approaches for controlling the fiber-matrix interface and improving the mechanical properties of CF epoxy composites.

Reinforcing carbon fiber epoxy composites with triazine derivatives functionalized graphene oxide modified sizing agent

Enhanced interfacial interactions of carbon fiber reinforced PEEK composites by regulating PEI and graphene oxide complex sizing at the interface

Enhancing interfacial strength of epoxy resin composites via evolving hyperbranched amino-terminated POSS on carbon fiber surface

Polymer matrix wave-transparent composites: A review

Chemical modification of carbon fiber with diethylenetriaminepentaacetic acid/halloysite nanotube as a multifunctional interfacial reinforcement for silicone resin composites

An amino-terminated nitrogen-rich layer of poly(cyclotriphosphazene-co-melamine) (PPM) coating was used to functionalize carbon fiber (CF) to strengthen the interfacial adhesion of CF reinforced copoly(phthalazinone ether sulfone)s (PPBES) through a facile in-situ polymerization. FTIR, Raman and XPS confirm the chemical bonds between CF and PPM. SEM and dynamic contact angle tests demonstrate that PPM coating can enhance surface wettability, roughnes of CF, which can improve interlaminar shear strength and flexural strength of CF/PPBES by 23.2% and 29.3% with no discernable decrease on tensile strength of CFs. According to DMA test, storage modulus and service temperature increase by 15 GPa and 6 °C. SEM observations certify that the failure mechanism transforms from interface failure for CF/PPBES to matrix failure and fiber broken for CF-PPM/PPBES. Moreover, the successful preparation of PPM coatings on CF surface provides new insights for the fabrication of advanced thermoplastic composites from readily available components via a facile route.

Amino-terminated nitrogen-rich layer to improve the interlaminar shear strength between carbon fiber and a thermoplastic matrix

Effect of Poly(phthalazinone ether ketone) with amino groups on the interfacial performance of carbon fibers reinforced PPBES resin

In the present study, we developed a novel approach to introduce amino group (–NH2), hydroxyl group (–OH) and sulfhydryl group (–SH) onto carbon fibers (CFs) using aromatic diazonium salts. Fourier transform infrared spectroscopy, Raman spectra, X-ray photoelectron spectroscopy, scanning electron microscope and single fiber tensile testing were performed to characterize the functional CFs. Interlaminar shear strength (ILSS) and flexural strength were carried out to investigate the interfacial properties of CFs/PPBES composites. Experimental results showed that –NH2, –OH and –SH were grafted on the CFs surface and increase the fibers surface roughness. The functionalization did not lead to any discernable decrease in the fibers tensile strength. It was obvious that ILSS and flexural strength were enhanced. Dynamic mechanical analysis and hydrothermal aging tests revealed that CF–NH2/PPBES had excellent high temperature mechanical properties and hydrothermal aging resistance. Additionally, the reinforcing mechanisms were also analyzed.

One-step functionalization of carbon fiber using in situ generated aromatic diazonium salts to enhance adhesion with PPBES resins

Improving the curing process and thermal stability of phthalonitrile resin via novel mixed curing agents

In this study, we describe a novel strategy to design and construct POSS-modified silane layer on carbon fiber (CF) to strengthen the interfacial adhesion and anti-hydrothermal aging behaviors of CF-reinforced copoly(phthalazinone ether sulfone)s (PPBES). POSS was first modified by 3-aminopropyltriethoxysilane (APS) to improve chemical reactivity. Without separation and purification, APS-c-POSS was used to functionalize CF to improve reactivity and ensure the covalent linkages between CF and POSS-modified silane layer. CF coated with POSS-modified silane layer was obtained by in situ hydrolysis of APS-c-POSS. FTIR and XPS confirmed the chemical bonds between CF and POSS-modified silane layer. Dynamic contact angle, dynamic wetting test and AFM tests demonstrated that POSS-modified silane coating can increase the wettability and roughness, which could improve interlaminar shear strength and flexural strength of CF/PPBES composites by 17.5 and 30.0% with slight enhancement on tensile strength of CF. The failure mechanisms of CF/PPBES composites with and without POSS-modified silane layer were both investigated by SEM in detail. Moreover, this layer was helpful to dynamic mechanical property and hydrothermal resistance of CF/PPBES composites. This study provides alternate strategy to modify CF with POSS, which will significantly broaden the application field of POSS in advanced composites.

One-pot strategy for covalent construction of POSS-modified silane layer on carbon fiber to enhance interfacial properties and anti-hydrothermal aging behaviors of PPBES composites

Zuoqiang Wu

Papers

Amino-terminated nitrogen-rich layer to improve the interlaminar shear strength between carbon fiber and a thermoplastic matrix

Effect of Poly(phthalazinone ether ketone) with amino groups on the interfacial performance of carbon fibers reinforced PPBES resin

One-step functionalization of carbon fiber using in situ generated aromatic diazonium salts to enhance adhesion with PPBES resins

Improving the curing process and thermal stability of phthalonitrile resin via novel mixed curing agents

One-pot strategy for covalent construction of POSS-modified silane layer on carbon fiber to enhance interfacial properties and anti-hydrothermal aging behaviors of PPBES composites