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Semi-aromatic poly (hexamethylene terephthalamide) (PA6T) oligomer (prePA6T) ultrafine powder, with a diameter of <5 μm, was prepared as an emulsion sizing agent to improve the impregnation performance of CF/PA6T composites. The prePA6T hyperfine powder was acquired via the dissolution and precipitation "phase conversion" method, and the prePA6T emulsion sizing agent was acquired to continuously coat the CF bundle. The sized CF unidirectional tape was knitted into a fabric using the plain weave method, while the CF/PA6T laminated composites were obtained by laminating the plain weave fabrics with PA6T films. The interfacial shear strength (IFSS), tensile strength (TS), and interlaminar shear strength (ILSS) of prePA6T-modified CF/PA6T composites improved by 54.9%, 125.3%, and 120.9%, respectively. Compared with the commercial polyamide sizing agent product PA845H, the prePA6T sizing agent showed better interfacial properties at elevated temperatures, especially no TS loss at 75 °C. The SEM observations also indicated that the prePA6T emulsion has an excellent impregnation effect on CF, and the fracture mechanism shifted from adhesive failure mode to cohesive failure mode. In summary, a facile, heat-resistant, undamaged-to-fiber environmental coating process is proposed to continuously manufacture high-performance thermoplastic composites, which is quite promising in mass production. [ABSTRACT FROM AUTHOR]

The electrical conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) can be conspicuously enhanced at low conductive filler contents with the formation of segregated structure in the conductive polymer composites (CPCs). Nevertheless, poor interface adhesion of segregated composites results in poor mechanical properties due to the selective distribution of conductive fillers. In this work, a flexible approach was applied to fabricate the poly(phenylene sulfide)/poly(arylene sulfide sulfone)/graphene nanoplates (GNPs) composite with a unique double percolated structure. This composite exhibits an outstanding EMI SE of 38.8 dB with only 3 wt % GNPs, which is comparable to that of the conventional segregated structure counterpart. What is more, the tensile strength and Young's modulus of double percolated composites with 3 wt % GNPs are remarkably improved by ~892 and ~274% compared to conventional segregated structure, achieving 37.7 and 1788.3 MPa, respectively. This work provides a valuable method for producing CPCs with high EMI shielding performances and outstanding mechanical properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48709. [ABSTRACT FROM AUTHOR]