This study show influence of alkaline treatment on sisal fiber (SF) in different composites of starch matrices (SM) and cellulose acetate matrices (CAM). SF were modified with an aqueous 0.5M NaOH solution. Composites were prepared in proportion of 3% fiber/matrix (m/m) using casting method. The samples were characterized by Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy by Attenuated Total Reflection (FTIR-ATR), Thermogravimetric Analysis (TGA) and Dynamic-mechanical thermal analysis (DMA). Through results obtained in FTIR and TGA, it was possible to verify that alkaline treatment partially removed hemicellulose and SF lignin. With SEM, best fiber/matrix adhesion in composites prepared with modified fiber (TSF) has been proven to change fibre morphology. Through DMA analysis it was possible to observe that after addition of SF and TSF, SM composites showed improvements in mechanical properties, while TGA showed an increase in initial temperature of thermal degradation in CAM composites with addition of fiber.
Due to growing concern about the environment, the use of biodegradable polymeric materials has been studied in order to minimize the environmental impact caused by synthetic polymers. Among these materials can be detached polymeric films containing corn starch, with low cost and available worldwide. This paper exhibits some characteristics of the starch and summarizes studies in which the authors present some properties of polymeric materials containing starch, especially mechanical and barrier properties, permeability to water vapor and the use of plasticizers.Keywords: Starch; film; biodegradable polymer; properties.
ResumoDevido à crescente preocupação com o meio ambiente, a utilização de materiais poliméricos biodegradáveis vem sendo estudada, a fim de minimizar os impactos causados por polímeros sintéticos. Dentre estes materiais podem ser destacados os filmes poliméricos contendo amido de milho, que possuem baixo custo e estão disponíveis em todo mundo. Este artigo exibe algumas características do amido e resume trabalhos nos quais os autores expõem algumas propriedades de materiais poliméricos contendo amido, principalmente, propriedades mecânicas, de barreira, permeabilidade ao vapor de água e a utilização de plastificantes.
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