Extrusão de filmes biodegradáveis de amido de milho termoplástico adicionado de quitosana plastificada

Abstract

The objective was to evaluate the effects of addition of 5 and 10% (m / m) of thermoplastic chitosan (TPC) in the development of biodegradable polymer blends of thermoplastic corn starch-chitosan obtained by extrusion. For this purpose were used corn starch, chitosan (Molecular weight: 90-310 KDa and Degree of deacetylation (GD): 75-85%), acetic acid, and glycerol (plasticizer). The biodegradable TPS/TPC blends were processed in a double screw extruder (co-rotating) in concentrations of 5% and 10% (w/w) of chitosan to obtain mixing pellets. Then these pellets were extruded in a single-screw extruder in which ribbons produced were hot pressed to obtain the films. The interactions between biopolymers and the blend morphology, thermal and mechanical properties were investigated. The possible interactions between the starch and chitosan thermoplastic molecules were evaluated by XDR and FTIR techniques. Scanning electron microscopy (SEM) analyzes showed a homogeneous fracture surface without the presence of starch granules or chitosan aggregates. Although the incorporation of thermoplastic chitosan has caused a decrease in tensile strength and rigidity, biopolymer films with better extensibility and thermal stability were obtained.