Abstract The strategy of combining the traditional reinforcement of glass fibers (GF) with lighter hollow glass microspheres (HGM) can afford to fulfill the need for potential light-weight and high-strength modern materials required in various sectors, such as automotive and aerospace industry applications. This work fabricated composites of PA6/GF/HGM by melting blending in a co-rotating twin-screw extruder, and subsequently, injection molded. The effects of HGM content on the density, morphological and mechanical properties were investigated and the PA6/GF/HGM composites properties were compared to the properties of the traditional PA6/GF (70/30) wt% composite, widely used today in automotive industries. With the increase of HGM amount in the formulations, a reduction of between 3 and 12% in density was achieved with a slight reduction in its mechanical properties, showing that this new strategy can be applied to replace the PA6/GF (70/30) wt% composite, providing a considerable weight reduction for these materials.

ABSTRACT Cellulose acetate nanofiber (CAN) have great potential for application as scaffolds, for combining properties such as high surface area, high porosity and interconnection between poles. In addition, these materials also have biodegradability, good mechanics and compatibility with living tissues, characteristics for the application of tissues in tissue engineering. The aim of the work was to produce and characterize CAN blankets by the electrospinning technique, in order to investigate the influence of processing parameters, the applied voltage and the working distance, on the morphological characteristics of nanofibers. Therefore, CAN blanks were produced using polymeric solutions at a concentration of 12% m/v in a combination of acetone/DMF solvents. The morphology of the nanofiber blankets was analyzed by images of scanning electron microscopy (SEM), the chemical characterization was performed by Fourier transform infrared spectroscopy (FTIR) and the thermal properties investigated by thermogravimetric analysis (TGA). The CAN produced showed a morphological structure in a cylindrical and elongated shape with diameters in the range of 154 to 185 nm, containing beads with dimensions between 0.5 and 4.0 nm, depending on the process parameters used. The CAN, obtained for the working distance of 12 cm and voltages of 12 and 15 kV, showed greater uniformity in the distribution of diameters with an average value of 184 ± 30 nm and an average of 23 ± 1 beads per area.

RESUMO Mantas de nanofibras de acetato de celulose (NFAC) possuem potencial aplicação como scaffolds por combinar elevada área superficial, elevada porosidade e interconexão entre os poros. Além disso, esses materiais também apresentam biodegradabilidade, boas propriedades mecânicas e compatibilidade com tecidos vivos, características essenciais para a aplicação na engenharia de tecidos. O objetivo deste trabalho foi produzir e caracterizar mantas de NFAC pela técnica de eletrofiação, visando investigar a influência dos parâmetros de processamento, tensão elétrica e distância de trabalho, nas características morfológicas das nanofibras. Para isso, foram produzidas mantas de NFAC utilizando soluções poliméricas em uma combinação dos solventes acetona/DMF, na concentração de 12% m/v. A morfologia das mantas de nanofibras obtida foi avaliada por microscopia eletrônica de varredura (MEV), a caracterização química foi realizada por espectroscopia no infravermelho com transformada de Fourier (FTIR) e as propriedades térmicas investigadas por análise termogravimétrica (TGA). As NFAC produzidas apresentaram estrutura morfológica no formato cilíndrico e alongado com diâmetro no intervalo de 154 a 185 nm, contendo contas com dimensões entre 0,5 e 4,0 nm, a depender dos parâmetros de processo utilizados. As NFAC obtidas para a distância de trabalho de 12 cm e tensões de 12 e 15 kV apresentaram maior uniformidade na distribuição dos diâmetros com valor médio de 184 ± 30 nm e com média de 23 ± 1 contas por área.