A new approach for preparation of metal-containing polyamide/carbon textile laminate composites with tunable electrical conductivity

Multiscale thermoplastic laminate composites based on polyamide 6 (PA6) dually reinforced by carbon fiber woven textile structures (CFT) and different micron-sized metal particles are prepared for the first time by microencapsulation strategy. In a first step, activated anionic ring-opening polymerization (AAROP) of epsilon-caprolactam is carried out in suspension, in the presence of different metal particles, to produce shell-core PA6 microcapsules (PAMC) loaded with 13-19% metal. In a second step, the loaded PAMC are distributed between CFT plies with fiber volume fractions V (f) = 0.25 or V (f) = 0.50 and then the ply arrays are consolidated by compression molding. Separately, metal-loaded PA6 hybrid composites are prepared by direct compression molding of PAMC and used to compare their properties to the CFT-metal laminates. Light- and scanning electron microscopy are used to study the morphology and the interfaces between the fillers and the polymeric matrix. These structural results are related to the mechanical behavior in tension and the electrical properties. A notable increase of the d.c. electrical conductivity in 7 orders of magnitude is observed for the CFT-metal laminates with respect to the neat PA6. This increase is accompanied by a 2.5-3.0 times growth of the Young's modulus and of the strength at break. It is concluded that the microencapsulation strategy can be applied to produce multifunctional CFT-metal-PA6 thermoplastic composites with tailored electrical and improved mechanical properties for advanced applications.The authors gratefully acknowledge the financial support of the project TSSiPRO NORTE-01-0145-FEDER-000015, supported by the regional operation program NORTE2020, under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund, as well as funding from FCT-Portuguese Foundation for Science and Technology within the strategic projects UID/CTM/50025/2013, LA25/2013-2014 and UID/FIS/04650/2013. FMO acknowledges also the PhD grant PD/BD/114372/2016 of FCT-Portugal (AdvaMTech-PhD Program in Advanced Materials and Processing) and PM the FCT SFRH/BPD/96227/2013 grant. Finally, ZZD is thankful to FCT for the SFRH/BSAB/130271/2017 personal research grant. Finally, SLM acknowledges funding from the Basque Government Industry Department under the ELKARTEK program.info:eu-repo/semantics/publishedVersio

Technology and development of self-reinforced polymer composites

In recent years there has been an increasing amount of interest, both commercially and scientifically, in the emerging field of "self-reinforced polymer composites". These materials, which are sometimes also referred to as "single polymer composites", or "all-polymer composites", were first conceived in the 1970s, and are now beginning to appear in a range of commercial products. While high mechanical performance polymer fibres or tapes are an obvious precursor for composite development, various different technologies have been developed to consolidate these into two- or three-dimensional structures. This paper presents a review of the various processing techniques that have been reported in the literature for the manufacture of self-reinforced polymer composites from fibres or tapes of different polymers, and so exploit the fibre or tape performance in a commercial material or product