“…The BP -CVD /PEEK composite film, CF/PEEK laminate, and BP/CF/PEEK laminate all have crystallization peaks of PEEK and CNTs. After fitting the XRD curves by splitting the peaks (as shown in Figure 7(c)–(f)), the crystallinity of PEEK polymer can be calculated by the following equation, 27 where Xc is the crystallinity, Ihkl is the integral intensity of the crystal diffraction peak, and Iα is the integral intensity of the amorphous peak. The crystallinity of PEEK powder, BP -CVD /PEEK composite film, CF/PEEK laminate, and BP/CF/PEEK laminate is 27.9%, 34.7%, 29.2%, and 35.7%, respectively.Figure 7.XRD curve and split-peak pattern: (a) XRD curve; (b) Crystallinity results; (c) Peak splitting curve of PEEK powder; (d) Peak splitting curve of BP -CVD /PEEK composite film; (e) Peak splitting curve of CF/PEEK laminate; (f) Peak splitting curve of BP/CF/PEEK laminate.…”
Carbon fiber/polyether ether ketone thermoplastic composites formed by automated fiber placement are susceptible to delamination damage. The interlaminar mechanical performance of carbon fiber/polyether ether ketone laminates can be enhanced in situ by doping carbon nanotubes in the plies. In this paper, the interfacial bonding energy between polyether ether ketone and buckypaper is analyzed by molecular dynamics. A novel method for preparing buckypaper/polyether ether ketone reinforcement materials and buckypaper/carbon fiber/polyether ether ketone multi-scale thermoplastic composites is proposed. The microstructure, crystallinity, and mechanical properties are analyzed. The results show that the polyether ether ketone resin fully penetrate the buckypaper interior and have a good interfacial bonding property. The buckypaper/polyether ether ketone composite films have a dense structure and are well-doped into the plies of carbon fiber/polyether ether ketone laminates. Compared with carbon fiber/polyether ether ketone laminates, the crystallinity, interlaminar shear strength, Model-I fracture toughness, and Model-II fracture toughness of buckypaper/carbon fiber/polyether ether ketone laminates are increased by 22.3%, 22.2%, 20%, and 9.5%, respectively.
“…The BP -CVD /PEEK composite film, CF/PEEK laminate, and BP/CF/PEEK laminate all have crystallization peaks of PEEK and CNTs. After fitting the XRD curves by splitting the peaks (as shown in Figure 7(c)–(f)), the crystallinity of PEEK polymer can be calculated by the following equation, 27 where Xc is the crystallinity, Ihkl is the integral intensity of the crystal diffraction peak, and Iα is the integral intensity of the amorphous peak. The crystallinity of PEEK powder, BP -CVD /PEEK composite film, CF/PEEK laminate, and BP/CF/PEEK laminate is 27.9%, 34.7%, 29.2%, and 35.7%, respectively.Figure 7.XRD curve and split-peak pattern: (a) XRD curve; (b) Crystallinity results; (c) Peak splitting curve of PEEK powder; (d) Peak splitting curve of BP -CVD /PEEK composite film; (e) Peak splitting curve of CF/PEEK laminate; (f) Peak splitting curve of BP/CF/PEEK laminate.…”
Carbon fiber/polyether ether ketone thermoplastic composites formed by automated fiber placement are susceptible to delamination damage. The interlaminar mechanical performance of carbon fiber/polyether ether ketone laminates can be enhanced in situ by doping carbon nanotubes in the plies. In this paper, the interfacial bonding energy between polyether ether ketone and buckypaper is analyzed by molecular dynamics. A novel method for preparing buckypaper/polyether ether ketone reinforcement materials and buckypaper/carbon fiber/polyether ether ketone multi-scale thermoplastic composites is proposed. The microstructure, crystallinity, and mechanical properties are analyzed. The results show that the polyether ether ketone resin fully penetrate the buckypaper interior and have a good interfacial bonding property. The buckypaper/polyether ether ketone composite films have a dense structure and are well-doped into the plies of carbon fiber/polyether ether ketone laminates. Compared with carbon fiber/polyether ether ketone laminates, the crystallinity, interlaminar shear strength, Model-I fracture toughness, and Model-II fracture toughness of buckypaper/carbon fiber/polyether ether ketone laminates are increased by 22.3%, 22.2%, 20%, and 9.5%, respectively.
“…In order to overcome them, the molecular design methodology was used by scholars all over the world to introduce new structures, such as naphthalene ring, [10][11][12][13][14] amides, 15 bisphenol, [16][17][18][19][20] an unsaturated five(or six)-membered ring, 21 fluorenyl 22,23 and oxadiazole, [24][25][26] into bismaleimide structure or added nucleophilic difunctional reagents to the maleic double bonds [27][28][29] with the aim of improving the processability and enhancing the fracture toughness of the corresponding cured without sacrificing thermostability and mechanical properties. However, this method has a low yield and a high cost.…”
3,3-Bis[4-(4-aminophenoxy)phenyl]phthalide (PPDA) and 4,4 0-bimaleimidodiphenyl-methane (BDM) were prepared via a Michael-type addition using molar ratio 1:2(PM 2), 1:3(PM 3) and 1:4(PM 4) in acetone as solvent and acetic acid as a catalyst. The chemical structures of prepolymers were characterized by hydrogen-1 nuclear magnetic resonance (1 H NMR) spectroscopy and Fourier transform infrared spectroscopy. These prepolymers exhibit good solubility in common organic solvents. The thermal properties of the prepolymers were investigated by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Composites composed of carbon cloth and the phthalide-containing Michael additiontype prepolymers (0.5% triphenylphosphine) were also prepared. The DMA results demonstrated that the resulting composites have excellent thermal stability. Besides, N,N-4,4 0-bismaleimidodiphenylmethylene (BDM) and O,O 0-diallyl bisphenol A (DABPA) resin blends were modified by PM 2. We investigated the effects of mole concentration of prepolymers on the curing process, mechanical properties, fracture toughness, and heat resistance of the modified resins. The investigations of the mechanical properties showed a complicated trend with an increase in prepolymer contents. When the proportion of PM 2 is 0.05, the impact strength of modified resins was increased by 121.3%. In addition, the moisture resistance of cured resins was improved with the increase in prepolymer contents.
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