Polyurethane with nano‐SiO₂ based surface sizing method for 3D printed carbon fiber reinforced nylon 6 composites

Abstract

Continuous carbon fiber reinforced polymer composite 3D printing has drawn more attention due to its ability to manufacture composite structures with complex shapes. The surface treatment of CF is necessary to improve the combination between carbon fiber (CF) and matrix. In this work, polyurethane with nano‐SiO2 (PU/SiO2) was used to size CF to enhance the compatibility of CF and nylon 6 (PA6). The chemistry and morphology of the CF were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The interface strength between CF and PA6 was tested by the fiber pull‐out test, and eventually obtained optimized concertation of PU/SiO2 sizing agents (with 25 wt% PU and 0.4 wt% nano‐SiO2). The results show that compared with untreated CF, the interfacial shear strength (IFSS) of CF and PA6 after sizing increased by 316.93%. In addition, several CF/PA6 composite specimens printed by a homemade composite 3D printer were used to do mechanical tests. The results show that the flexural strength increased by 33.87%, the tensile strength increased by 20.75%, and the interlaminar shear strength (ILSS) increased by 66.54%.

Interfacial performance and build orientation of 3D‐printed poly(ether‐ketone‐ketone) reinforced by continuous carbon fiber

“…It demonstrates that PEI did improve the adhesion between CCF and PEKK. However, a higher concentration made more PEI adhere to the surface unevenly as shown in Figure 2C, which resulted in damage first occurring in the interior of PEI under external force 34 and a worse interface than 5PEI@CCF/PEKK.…”

“…It demonstrates that PEI did improve the adhesion between CCF and PEKK. However, a higher concentration made more PEI adhere to the surface unevenly as shown in Figure 2C, which resulted in damage first occurring in the interior of PEI under external force 34 and a worse interface than 5PEI@CCF/PEKK. DMA was also tested to judge the fiber-matrix interfaces of CFRTPCs as shown in Figure S6, 23 which displays the storage modulus (E') with the temperature of CCF/PEKK and PEI@CCF/PEKK.…”

“…Mechanical properties. (A) Flexural properties, (B) ILSS, (C) ILSS of different build orientations, (D) comparison with ILSS of previous work 9,25,28,34,37,38. F I G U R E 7 Optical microscope photos at the cross-sections of flexural failure: (A) CCF/PEKK, (B) 5PEI@CCF/PEKK, (C) 9PEI@CCF/PEKK.…”

Vat photopolymerization printing of strong tear‐resistance and stretchable polyurethane elastomer for highly sensitive strain sensors

“…In addition, comparing the tear energy of PPU/SiO 2 materials with different SiO 2 contents (Figure S10), it can be obtained that the SiO 2 content of 0.5 wt.% possesses the highest tear energy (35.44 KJ/m 3 ), which is significantly better than the other groups. 6,24,30 As an effective strategy, increasing the energy dissipation in the structure has been proven to enhance the strength and toughness of elastomers. 31 The aromatic PUA prepolymer, as the main body, possesses a strong and robust covalent crosslinking network, as well as abundant hydrogen bonding, which offers the inherent mechanical qualities.…”

“…The above experiments demonstrate the outstanding tear resistance and mechanical stability of the PPU/SiO 2 -0.5 elastomer material, rendering it a high-quality candidate for strain sensor stretchable substrates. At the moment, most strain sensors are produced by compounding highly conductive materials, such as metals, 34 graphene, 35 carbon nanotubes, 30 etc. Yet, the compatibility of these materials with the elastomeric matrix is inferior, and the addition of a mass of conductive fillers could lead to the deterioration of the mechanical properties of the elastomer.…”