Suchergebnisse

Structural health monitoring (SHM) is a non-destructive process of collecting and analysing data from structures to evaluate their conditions and predict the remaining lifetime. Multifunctional sensors are increasingly used in smart structures to self-sense and monitor the damages through the measurements of electrical resistivity of composites materials. Polymer-based sensors possess exceptional properties for SHM applications, such as low cost and simple processing, durability, flexibility and excellent piezoresistive sensitivity. Thermoplastic, thermoplastic elastomers and elastomer matrices can be combined with conductive nanofillers to develop piezoresistive sensors. Polymer, reinforcement fillers, processing and design have critical influences in the overall properties of the composite sensors. Together with the properties of the functional composites, environmental concerns are being increasingly relevant for applications, involving advances in materials selection and manufacturing technologies, In this scenario, additive manufacturing is playing an increasing role in modern technological solutions. Stretchable multifunctional composites applications include piezoresistive, dielectric elastomers (mainly for actuators), thermoelectric, or magnetorheological materials [1]. In the following, piezoresistive materials and applications will be mainly addressed based on their increasing implementation into applications. ; Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019 and UID/EMS/00151/2019. The authors thank the FCT for financial support under SFRH/BPD/110914/2015 (P. C) and SFRH/BPD/117838/2016 (J. Pereira) grants. Financial support from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA ...

Polymer composites based on poly(vinylidene fluoride) (PVDF) filled with carbon nanotubes (CNT) decorated with metal nanoparticles (NP) of cobalt, nickel, platinum and palladium have been produced. The CNT nano fillers decorated with metal NP were synthesized by a modified wet impregnation method and their structural, morphological and thermal properties were evaluated. The metal NP ranging from 2 to 10 nm were found well dispersed on the CNT structure. The structural, optical, thermal and electrical properties of the metal/CNT/PVDF composite films demonstrate that the inclusion of the nanofillers leads to the nucleation of the gamma-PVDF phase (up to 90%) and enhance the thermal properties (higher melting point) of the polymer. The nanofillers also proved to be suitability to tailor the optical properties of the polymer composite films and lead to an increase in the d.c. electrical conductivity (up to 10(-13)S/cm). Thus, the reported metal/CNT nanofillers are suitable to tune PVDF polymer properties towards specific applications. ; This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the strategic project UID/FIS/04650/2013, by FEDER funds through the COMPETE 2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) with the reference project POCI-01-0145-FEDER-006941. JNP wish to thank the financial support of the project Centro-01-0145-FEDER-000017 - EMaDeS - Energy, Materials and Sustainable Development, co-financed by the Portugal 2020 Program (PT 2020), within the Regional Operational Program of the Center (CENTRO 2020) and the European Union through the European Regional Development Fund (ERDF). JO wish to thank the FCT for the SFRH/BD/98219/2013 grant. The authors also acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including the FEDER financial support), and financial support from the Basque Government Industry Department under the ELKARTEK ...