Due to its ester bonds, poly(lactic acid) (PLA) undergoes biodegradation in humid environments, attracting market attention. The goal of this work was to observe the biodegradation in garden soil of PLA nanocomposites with neat (PLA/CNW) and surfactant modified cellulose nanowhiskers (PLA/CNW/S). Three types of surfactants were tested: poly(ethylene glycol) monooleate (PEGMONO) and poly(ethylene glycol) with molecular weight of 300 and 1000 Da. The films were obtained by solution casting, cut in strips of (2x2) cm and buried in garden soil, monitoring the temperature and humidity. After 90, 120 and 150 days changes were observed in the films by visual inspection, polarized light microscopy, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The results showed that the addition of surfactant favored the biodegradation of nanocomposites and that PLA/CNW/PEG1000 showed the fastest biodegradation rate.

A técnica de eletrofiação é conhecida desde a década de 1930, porém, somente com o advento das novas aplicações da nanotecnologia esta importante técnica foi re-descoberta. As potencialidades de nanofibras, de tamanhos da ordem de 50 a 500 nm e com extensão micrométrica, têm sido investigadas para diferentes materiais, com resultados promissores em diferentes aplicações. Nesta primeira parte, este trabalho de revisão propôs-se a detalhar as bases fundamentais do processo de eletrofiação. São descritas as influências das variáveis de processo, como campo aplicado, distância de trabalho, velocidade de rotação do coletor e de injeção da solução. Variáveis associadas ao sistema, como tipo de solvente e polímero de interesse, também são discutidas.

The electrospinning technique has been known since the 1930s, but only with the advent of new nanotechnology applications this technique was re-discovered and became important for production of nanomaterials. The potential for obtaining different nanofibers with sizes ranging from 50 to 500 nm and micrometer length has been investigated for different materials, with promising results in different applications. The first part of this review is aimed at describing the fundamentals of the electrospinning process. We describe the influence of process variables such as applied field, working distance, speed of rotation of the collector and solution injecting flow rate. The variables associated to this system, such as type of solvent and polymer of interest, are also discussed.

Em artigo de revisão anterior[1], o processo de eletrofiação foi discutido, incluindo suas bases teóricas e experimentais, e a obtenção de diferentes nanofibras de materiais poliméricos. Neste segundo artigo de revisão, são abordados os aspectos relacionados à aplicação de materiais eletrofiados em diferentes áreas, como médica, agrícola, sensores, processamento de outros materiais, entre outras. São também discutidas as técnicas de caracterização utilizadas mais frequentemente nestes materiais, e suas potencialidades. Esta segunda revisão é complementar à anterior e segue, em seus aspectos gerais, a mesma terminologia.

In our previous review[1], the process of electrospinning was discussed on the basis of theoretical and experimental aspects toward preparation of different polymeric nanofibers. In this second review, we focus on the aspects related to the application of electrospun materials in various fields such as medicine, agriculture, sensors, and processing of other materials. We discuss the most often characterization techniques used for these materials and their potential. This review complements the previous one and uses the same terminology.