Navegando por Palavras-chave "Blendas Poliméricas"

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    Eletofiação da lignina kraft e da poliacrilonitrila/lignina para produção de nanofibras poliméricas visando a obtenção de nanomantas de carbono
    (Universidade Federal de São Paulo (UNIFESP), 2019-02-22) Nahra, Lara Robert [UNIFESP]; Guerrini, Lilia Muller [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The electrospinning of polymer materials from renewable sources has been highlighted by the innumerable possibilities of applications and because it presents considerable potential for obtaining products with appropriated properties of application, lower cost of raw material and above all, less environmental impact. Among these materials, we highlight Kraft lignin (LK), a by-product resulting from the paper production process and cellulose, as an alternative for the production of LK polymer nanomats and blends composed of LK using electrospinning technique. Thus, the objective of this work consists in preparation of polyacrylonitrile (PAN), LK and PAN/LK nanomats by electrospinning technique via polymer solution. The effect of LK concentration on the preparation of PAN/LK and nanomats blends was evaluated in order to determine the maximum concentration of LK for polymer nanomats production. The chemical modification of LK was demonstrated by means of the hydrogen nuclear magnetic resonance (1H-NMR) and Fourier transform infrared spectroscopy (FT-IR). In spite of this, it was not possible to obtain nanomats of LKa and LKg employing different electrospinning strategies. It was possible to obtain homogenous and undamaged nanomants from the PAN/LK blends containing 0 to 60% wt% of LK. Nanomats with nonhomogeneous fibers and with the presence of bead defects were produced from PAN/LK blends containing 70 and 80% wt% of LKg. From the thermogravimetric analysis (TGA) it was verified that the addition of lignin provided a lower thermal resistence of the mats, from 317 °C for the PAN mats to 278 °C for the PAN/LKp mats at 40/60% wt%, and lower mass loss of the mats, from 36.59% for the PAN mats to 50.72% for the PAN/LKp mats at 40/60% wt%.