Biodegradable films are widely exploited among scientists nowadays. Their positive environmental impact, besides their potential to promote better food conservation and an increase in shelf life motivate research in this field. Availability, low cost and biodegradability of starch increase the interest of using this material to produce biodegradable films. However, starch films tend to be brittle and they need addition of a plasticizer to enable their usage. In this work, starch films were synthesized with different carboxylic acids as plasticizers, aiming to observe the effect of the acids' chain size in the final films properties. Oxalic, succinic and adipic acids were used. The materials were produced by casting and characterized by DSC, TG, XRD, FTIR and SEM. It was observed that the acids chain size influenced on the thermal and structural properties of the films.

The agribusiness generates countless sources of biomass that are not appropriately and / or adequately utilized, turning them into industrial wastes. This study aims to explore the Arrowroot fiber as a source of raw material for the cellulose nanowhiskers production by acidic hydrolysis. Hydrolyses were carried out varying the temperature and the sulfuric acid concentration, with the hydrolysis reaction time fixed and constant stirring. The nanowhiskers of cellulose extracted from the arrowroot fibers has great potential as reinforcing agents in the nanocomposites production regarding to others cellulose nanowhiskers sources, because they have shown a similar performance as the other fibers, good thermal stability, crystallinity index and good aspect ratio as compared to the literature.

Weather conditions and the Brazilian fertile soil contribute to abundant natural resources in a wide variety of fiber types. These fibers have attracted interest in Materials Science area for such characteristics as: low cost, high elasticity modulus and renewability. In this context, the objective of this work was physical, chemical and morphological characterization of purple banana fibers (Musa velutina). The following characterizations were employed: TG, DSC, FTIR, XRD, SEM, density, mechanical properties and chemical composition. The results showed that the purple banana fibers had good thermal, mechanical, morphological and structural properties. Treatment with sodium hydroxide was efficient in removing amorphous regions present on the fiber as evidenced by the chemical composition, increasing the crystallinity index. Therefore, the purple banana fiber is promising as reinforcement in polymer matrices.