PROPERTIES OF CASTING FILMS FROM NATIVE A ND CHEMICALLY-MODIFIED STARCHES

Starch acetates and hexanoates were prepared from potato, wrinkled pea , and amylomaize starch of low and high degrees of substitution (DS=0. 1-2.8). These products were used as raw materials for film casting in a laboratory scale. The objective of this work was to study the influe nce of starch types and derivatisations on film properties, i.e. tensi le strength and elongation as well as water absorption and solubility. After the addition of softeners transparent, flexible, and water solu ble films were obtained from unsubstituted and partially substituted s tarches, while totally substituted starch derivatives (triacetates and hexanoates) resulted in films insoluble in water. The well-known amyl ose advantage of film casting was found only after derivatisation. In the case of wrinkled pea and amylomaize starch considerable improvemen ts of mechanical film properties, both tensile strength and elongation , were achieved even at low degrees of substitution.