Physical, structural, thermal and mechanical properties of starch-based materials from pehuen seeds (Araucaria araucana (Mol) K. Koch)

CASTAÑO, J.; RODRÍGUEZ, S.; CARRASCO, C.; BOUZA, R.:
Reports of the VII International Conference on Materials Medellín, Colombia, Vol. 126, 107-113, (2014).

Abstract

Starch isolated from pehuen seed (Araucaria araucana (Mol) K. Koch) was employed for producing thermoplastic starch (TPS) and pehuen cellulosic husk was used as reinforcement for starch-based materials composites. Starch, husk, TPS and composites were characterized. Granules pehuen starch are rounded and small (12-21 μm), with an amylose content range 38– 40%, a crystalline C-type structure and thermally stable, with decomposition temperature above 300 ◦C. The effect of plasticizer type (glycerol and sorbitol) and starch/plasticizer ratio on TPS properties was also investigated. X-ray diffraction patterns of TPS showed the formation of processing-induced crystallinity, which depended on plasticizer employed. Sorbitol plasticized TPS provided a material with more brittles and less flexibility. In contrast, glycerol plasticized TPS was tough and ductile. The tensile strength of TPS decreased with the increase in plasticizer content. The incorporation 5 y 10 wt.-% of pehuen husk improved considerably the thermal stability and mechanical properties of the studied composites.

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