Facultad de Ciencias Básicas

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Evaluación de las propiedades fisicoquímicas del almidón termoplástico en presencia de ácido láctico
(Universidad Santiago de Cali, 2019) Pastrana Gutiérrez, Isabel
The thermoplastic starch was modified with lactic acid in the molten state, using two types of starches (achira and potato) and two different plasticizers, glycerol and sorbitol. These components were used in a 70:30 ratio (starch: plasticizer) and the addition of acidic agent was carried out in portions of 3, 6 and 9% by weight. These mixtures were obtained in a torque rheometer at 130 ° C for 10 min. The thermal characterization performed showed greater stability for the samples of TPSL> TPS, the values in the temperature of degradation varied between 230 ° C to 280 ° C, while for the thermal transitions corresponding to the temperature of gelatinization and fusion they showed a decrease in the crystallinity for the samples with 6% oleic acid, these results were consistent with the morphological analysis. The results derived from the oscillatory rheological analysis had a viscous behavior in the TPS samples, while the presence of the acid generated viscous to elastic transitions. Finally, a reduction in the hydrophilicity of the modified TPS was evidenced because some of the samples increased the value of the contact angle by up to ~ 46%.