Suchergebnisse

Opposition against austerity was the cornerstone to the protests which took place in since 2010. In Portugal, the first signs of mobilization came from the unions, although the emergence of new actors allowed the movement to be socially amplified. This article reflects on the 14th of November 2012 general strike to, from the Portuguese case, explore its insertion in this period's contentious politics, not only as to its transnational dimension – within the European Union framework -, but also as to the relationship between actors – particularly between unions and the new political actors. While facing a political agenda set on producing major changes in the social and labour regime, unions found increased challenges in the use of their ultimate instrument of struggle – strikes -, specially considering its power bases, already quite weakened before this mobilization cycle. ; info:eu-repo/semantics/publishedVersion

This work reports the development of renewable cellulose nanocrystal (CNC) and ionic liquid (IL) hybrid materials for bending actuator applications. For this purpose, cellulose nanocrystals with different surface charges (neutral, positive and negative) were prepared and increasing amounts of the IL 2-hydroxy-ethyl-trimethylammonium dihydrogen phosphate ([Ch][DHP]) (10 and 25 wt%) were incorporated into the CNC hosting matrix. The morphology of the samples was evaluated, proving that both surface charge and IL incorporation do not affect the characteristic layered structure of the CNC. Atomic force microscopy results reveal a sea-island morphology in the hybrid films, where CNC bundles are surrounded by [Ch][DHP]-rich regions. An increase in the electrical conductivity is observed upon IL incorporation into the CNC matrix, regardless of the CNC surface charge. The highest electrical conductivity values are observed for IL/CNC (+) 25 wt% with an electrical conductivity of 3.18 x 10(-5) +/- 2.75 x 10(-7) S cm(-1) and IL/CNC (-) 10 wt% (1.26 x 10(-5) +/- 5.92 x 10(-6) S cm(-1)). The highest bending displacement of 2.1 mm for an applied voltage of 4.0 Vpp at a frequency of 100 mHz was obtained for the IL/CNC (+) 25 wt% composite, demonstrating the suitability of cellulose to develop soft actuators. ; The authors thank FCT - Fundacao para a Ciencia e Tecnologia - for financial support under the framework of the Strategic Funding UID/FIS/04650/2019 and UID/QUI/50006/2019 and projects PTDC/BTM-MAT/28237/2017, PTDC/EMD-EMD/28159/2017 and PTDC/FIS-MAC/28157/2017. D. M. C., C. M. C. and L. C. F. also acknowledge FCT for the grants SFRH/BPD/121526/2016, SFRH/BPD/112547/2015 and SFRH/BD/145345/2019, respectively. The authors acknowledge funding by the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry and Education Department under the ELKARTEK and PIBA (PIBA-2018-06) programs, ...

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 ...

Photocurable thermochromic and humidity responsive materials based on polyurethane acrylated (PUA) and bis(1-butyl-3-methylimidazolium) tetrachloronickelate ([Bmim]2[NiCl4]) ionic liquid (IL) have been prepared with varying IL content up to 40 wt% within the polymer matrix. The influence of IL content on the photopolymerization process, morphology, Young modulus and electrical conductivity of the materials was evaluated. All materials present a total polymer conversion of at least 88%. The presence of the IL influences the morphology of PUA, being observed a porous network structure upon IL incorporation into the PUA matrix. All samples show a Tg around room temperature, which is independent of the IL content and a Young modulus that decreases with the IL content. All composites exhibit humidity dependent thermochromism from colourless to blue. Further, the influence of the relative humidity in the colour change was accessed for the sample containing 20 wt% [Bmim]2[NiCl4], being observed that the colour variation is thermally activated and humidity governed, being 55% the minimum value of the relative humidity for colour change to occur. ; FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/FIS/04650/2020, UID/EEA/04436/2020 and UID/QUI/0686/2020 and project no. PTDC/FIS-MAC/28157/2017. The authors thank funding by the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and under the Operational Programme "Competitiveness and Internationalization" - Research and Development (R&D) and Innovation to SMEs – R&D Individuals Projects, grant agreement number 038397. M. S. also acknowledge the National Research grant "Juan de la Cierva" FJCI-2017-31761. Financial support from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA programs is also acknowledged. LCF and DCM also thank the grant ...