Mechanical characterization of starch-vegetal fibre composites

LUCIA FAMA; MARIA PAULA ANDERICA; LIA GERSCHENSON; SILVIA GOYANES

Mar del Plata, Pcia de Buenos Aires

Conferencia; 3rd Internacional Conference on Science and Technology of composite materiales, COMAT; 2005

Universidad Nacional de Mar del Plata y Universidad de Perugia

Mechanical characterization of starch-vegetal fibre composites L. Famá,1,2, M. P. Andérica1,2, L.N. Gerschenson, 2,3 S. Goyanes1,3 1 Laboratorio de Polímeros y Materiales Compuestos, Dep. De Física, FCEN - UBA.  Ciudad Universitaria, Pab. 1, C1428EGA, Ciudad Autónoma de Buenos Aires, Argentina. 2Dep. de Industrias, FCEN-UBA. Ciudad Universitaria, Pab. Industrias, C1428EGA, Ciudad Autónoma de Buenos Aires, Argentina. 3Consejo Nacional de Investigaciones Científicas y Tecnológicas, CONICET, Argentina The importance of the incorporation of vegetal fibers to starch based edible films is founded not only on its high nutritional value but also in the improvement of the functional properties of the films. The objective of this research was to study the influence of wheat bran content in the mechanical response of edible films based on tapioca starch and containing glycerol and potassium sorbate. The effect of three fractions in weight of fibre 0.17 %; 1.50 % and 3.00 %  were analyzed.  It was observed that the inclusion of smaller quantities of wheat bran duplicated the storage modulus without a significant modification in the glass transition temperature associated with the glycerol rich-phase. Anyhow, the composites with high fibre content suffered a slight displacement of that transition to higher  temperatures, showing the characteristic increase in width of the relaxation peak. In all studied cases, films showed deformations higher than 70 %, without rupture, and tension increased with fibre content. For the composite with 0.17 % wheat bran content, the increase of tension (deformation: 70 %) was 60 % with fibre addition. The mechanical response of the composites was explained in relation to X-Ray and moisture content results.