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Functionalization of CNTS with maleic anhydride
Araújo, Rui Filipe; Paiva, M. C.; Proença, M. Fernanda R. P.; Silva, C. J. R.The outstanding properties of carbon nanotubes (CNTs) [1] are mainly related with their unique structural features. However, the high π-π staking between the tubes is a major drawback for their manipulation and interaction with other materials. Chemical functionalization has been used as a convenient tool to improve their performance in various applications [2]. The work reports the functionalization of multi-...
The diels-alder cycloaddition reaction of 1,3-butadiene to MWCNTs
Araújo, R. F.; Proença, M. Fernanda R. P.; Silva, C. J. R.; Paiva, M. C.In this study the funtionalization of MWCNTs with 1,3-butadiene generated in situ from solfolene was investigated. The reaction was studded at two different temperatures (100ºC and 150ºC), mass ratios (CNTs:Sulfolene of 1:1 and 1:2) and different time reaction (2, 4 and 7 days). Thermogravimetric analysis (TGA) showed high degree of functionalization in a range of 10 % to 23 % in weight loss at 800 ºC. The acid...
Incorporation of CdS nonoparticles from colloidal solution into optically clear...
Boev, Victor I.; Soloviev, A.; Silva, C. J. R.; Gomes, M. J. M.Nanocomposite materials based on an organic-inorganic ureasilicate matrix with embedded CdS nanoparticles were produced and characterized by optical (UV/Vis), FTIR, secondary ion mass spectroscopy, inductively-coupled plasma optical emission and steady-state photoluminescence measurements. The ureasilicate precursor was obtained by the reaction between silicon alkoxyde modified by isocyanate groups and polyethy...
Effect of concentration of the diazoalcene molybdenum complex immobilized in ur...
Costa, F.; Fonseca, A. Maurício C.; Silva, C. J. R.; Neves, Isabel C.The complex trans-[FMo(NNCHCHCHCH2CH3)(Ph2PCH2CH2PPh2)2][BPh4], was dispersed in a hybrid matrix synthesized by a sol-gel process. The host matrix of the so-called ureasil is a network of silica to which oligopolyoxyethylene chains [POE, (OCH2CH2)n] are grafted by means of urea cross-links. The free complex and sol-gel materials were characterized by thermal analysis (DSC), surface analysis (XPS) and spectrosco...
Synthesis and characterization of a sol-gel derived ureasilicate hybrid organic...
Boev, Victor I.; Silva, C. J. R.; Hungerford, Graham; Gomes, M. J. M.A hybrid organic-inorganic material filled with in situ generated inorganic particles has been synthesised by the homogeneous precipitation of CdS from aqueous solutions of Cd(NO3)2 and CH3CSNH2 . These highly transparent, homogeneous and flexible CdS doped xerogels were prepared by the sol-gel technique using, as precursors, organically modified silicon alkoxide (3-isocyanatepropyltriethoxysilane) and a di-ami...
Preparação e caracterização de electrólitos poliméricos
Silva, C. J. R.A preparação e o estudo dos electrólitos poliméricos requer condições instrumentais particularmente exigentes pelo que o primeiro objectivo do trabalho, descrito nesta dissertação, consistiu no desenvolvimento de um sistema que assegurasse o preciso controlo destas condições. A optimização dos procedimentos seguidos para a preparação dos electrólitos poliméricos, na forma apropriada, foi um passo fundamental de...
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