Produção e caracterização de filmes biodegradáveis de amido de mandioca e goma xantana

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

15/03/2010

RESUMO

Biodegradable plastics from renewable, especially agricultural sources, have been the aim of constant scientific interest in recent years. Cassava starch is an abundant, renewable and low cost natural polymer considered a promising substitute for oil-based plastic packaging materials. However, starch-based plastic films tend to show low resistance to moisture and high degree of mechanical properties variation when submitted to different environmental conditions. The aim of this work was to produce biodegradable films by casting and extrusion from different combinations of cassava starch and xanthan gum, and characterize them according to microstructure, water affinity, optical, mechanical and barrier properties in order to evaluate xanthan gum effect on improving starch films. Films were produced by casting and extrusion from six different starch/xanthan gum combinations (0, 2, 4,, 6, 8 and 10% of xanthan gum related to the total mass), containing glycerol as plasticizer (20% of the total mass). Scanning electron microscopy (SEM) of extruded films containing xanthan gum showed reticulated surface and smooth interior, suggesting that the gum concentrates mostly on the surface. Films produced by casting showed homogeneous both surface and interior; in general these films showed less opacity, lower water vapor permeability and higher stress at break than films produced by extrusion, establishing that the production process can affect the properties of starch and xanthan gum films. Xanthan gum addition did not demonstrate significant influence on starch films properties, independent of the production process. It is possible that the non homogeneous interaction between xanthan and starch induced the observed results, namely, xanthan gum did not have significant effect at lowering starch films water affinity, therefore, these films did not show any improvement of mechanical properties stability when submitted to different environmental conditions.

ASSUNTO(S)

filmes biodegradáveis - propriedades mecânicas plásticos - extrusão filmes plásticos biodegradable films mechanical properties plastics extrusion plastic films

Documentos Relacionados