Search

Carbon fiber (CF) reinforced thermoplastic polyethylene terephthalate (PET) laminate composites with light weight, high strength, excellent damage tolerance, and recyclability have garnered increasing attention. However, the weak interface between inert CF and PET resin, as well as the difficulty of impregnating the considerably high melt viscosity of PET matrix into the CF bundles, have impeded further development of the CF/PET composites. To settle the challenge, the chopped ultra-thin CF tapes (thickness of 40 μm and length of 30 mm) reinforced PET composite laminates were prepared by mechanical spreading technology, following with random stacking and molding technology via the plasma treatment and PET/carbon nanotubes (CNT) sizing. As the results, the optimal interlaminar shear strength (ILSS), tensile strength, and Young's modulus of the chopped ultra-thin CF tapes reinforced PET composites (with 1.0 wt% CNT) achieved 42.4 MPa, 780.9 MPa, and 47.8 GPa, which increased by 41.9 %, 40.7 %, and 68.9 %, respectively, compared to unmodified CF/PET composites. Especially, the porosity of the composites reached 0.68 %, decreased by 84.3 %. Therefore, combining the easy infiltrability of chopped ultra-thin CF tapes technology and the multiscale interfacial reinforced strategy (plasma treatment and PET/CNT sizing) is an effective way to reduce the porosity and enhance the mechanical properties of the thermoplastic composites. [Display omitted] • Quasi-isotropic chopped CF tapes reinforced PET composites with low porosity. • Ultra-thin CF tapes PET composites with quasi-isotropic mechanical properties. • Multiscale interface reinforcing of mechanical interlocking and chemical bonding. • Matrix-interface integrated reinforcement of PET/CNT interfacial transition layer. [ABSTRACT FROM AUTHOR]

With the rapid development of high-frequency communication and large-scale integrated circuits, insulating dielectric materials require a low dielectric constant and dielectric loss. Poly (aryl ether ketone) resins (PAEK) have garnered considerable attention as an intriguing class of engineering thermoplastics possessing excellent chemical and thermal properties. However, the high permittivity of PAEK becomes an obstacle to its application in the field of high-frequency communication and large-scale integrated circuits. Therefore, reducing the dielectric constant and dielectric loss of PAEK while maintaining its excellent performance is critical to expanding the PAEK applications mentioned above. This study synthesized a series of poly (aryl ether ketone) resins that are low dielectric, highly thermally resistant, and soluble, containing cyclohexyl and diphenyl fluorene. The effects of cyclohexyl contents on the properties of a PAEK resin were studied systematically. The results showed that weakly-polarized cyclohexyl could reduce the molecular polarization of PAEK, resulting in low permittivity and high transmittance. The permittivity of PAEK is 2.95–3.26@10GHz, and the transmittance is 65–85%. In addition, the resin has excellent solubility and can be dissolved in NMP, DMF, DMAc, and other solvents at room temperature. Furthermore, cyclohexyl provided PAEK with excellent thermal properties, including a glass transition temperature of 239–245 °C and a 5% thermogravimetric temperature, under a nitrogen atmosphere of 469–534 °C. This makes it a promising candidate for use in high-frequency communications and large-scale integrated circuits. [ABSTRACT FROM AUTHOR]

To tackle the challenge for materials in the fields such as deep space exploration with flexibility, light weight, high strength, and highly efficient neutron shielding properties, a novel organic-inorganic composites has been developed in this study. Based on ultrahigh molecular weight polyethylene (UHMWPE) fibers self-reinforcing linear low-density polyethylene (LLDPE) matrix method and hierarchical scattering and absorption strategy, a flexibly and light-weight multilayer structure has been designed with alternating gadolinium oxide (Gd 2 O 3)/LLDPE layers and UHMWPE fiber layers by stacking hot-pressing to augment the mechanical properties and neutron shielding efficiency of the composites. Moreover, PE, including UHMWPE fibers and LLDPE matrix, and Gd 2 O 3 has been utilized as neutron shielding element to enhance its neutron scattering and absorption capability via an abundance of hydrogen atoms and Gd element. The neutron shielding performance of the multilayer Gd 2 O 3 /UHMWPE/LLDPE composite, with a low density of ca. 1 g/cm3, has been verified by neutron shielding test and a simulation method of equivalent Gd areal density (EGdAD). As a result, an ca. 90.0% neutron shielding efficiency can be achieved with only 2 mm thickness of the composites (with 20 wt% Gd 2 O 3), and an EGdAD value of 0.0489 g/cm3 is required to achieve 99% shielding efficiency. Moreover, the composites have a significant improvement in the tensile strength and modulus, with an average increase of 1000% (15.86 MPa–179.95 MPa) and 1238% (230.53 MPa–2787.55 MPa) compared to the Gd 2 O 3 /LLDPE composites, respectively. The comprehensive performance of our developed multilayer Gd 2 O 3 /UHMWPE/LLDPE composites is superior to previously reported results in the literatures. Therefore, it has great application prospect in the various fields like aerospace. [Display omitted] [ABSTRACT FROM AUTHOR]