Efeito de tratamento térmico em biomaterial de amido termoplástico

Abstract

Starch based Biopolymers have been arousing the interest of different areas, given their low price, easy production and biodegradability. Compared with ordinary plastics, bioplastics are more environmentally friendly, but still do not have ideal properties for industrial use, their main setback being its non-stability due to retrogradation. The objective of the present work was to make thermal treatments in samples of thermoplastic starch with different proportions of glycerol and citric acid at -18 ° C, 4 ° C, 30 ° C and 60 ° C for 48h in order to increase the speed of recrystallization ( stabilizing it), and after that, characterizing and analyzing the different properties of the material, potentializing its use capacity in additive manufacture.It was possible to obtain monofilaments from the extrusion process with all the different compositions. Only the heat treatments of 30 ° C and 60 ° C affected material properties significantly, probably by increasing the amount of crosslinking and / or retrogradation in the sample or by approaching their chains. Glycerin was the most influential component in the mechanical properties of the thermoplastic starch presumably by replacing the bonds between the starch chains by plasticizer starch bonds. The tested samples, especially those with the addition of citric acid, are not suitable for 3D printing because the acid narrows the temperature range between melting and decomposition of the material and hydrolyzes the starch.