A flexible film was obtained from a blend of cassava thermoplastic starch and polylactic acid, using maleic anhydride as coupling agent. For this, an experimental design with three factors was used: polylactic acid content, coupling agent content, and temperature profile of the blown extrusion. It was found that the three factors generated significant differences on the response variables of tensile mechanical properties individually as in their triple interaction. Differential scanning calorimetry (DSC) was used by understanding the behavior of thermal properties of TPS/PLA blends with and without coupling agent, finding similar results between both. From this, the combination with 28% polylactic acid, 0.87% coupling agent, and 155.75°C temperature profile permitted the obtaining of a material with outstanding mechanical properties and offered advantages from the economic point of view.

ResumenEl objetivo de esta investigación fue evaluar el efecto de la temperatura de procesamiento y de la concentración del aditivo Tween 80 (un surfactante hidrofílico usado como aditivo alimentario) sobre las propiedades mecánicas de tensión de una película flexible elaborada a partir de almidón de yuca termoplástico (TPS), ácido poliláctico (PLA) y policaprolactona (PCL). Se realizó un diseño experimental para determinar el perfil de temperatura y concentración de Tween 80. Posteriormente se escogió el tratamiento con los resultados más sobresalientes en las propiedades mecánicas y se comparó con una película patrón (sin Tween 80). Los valores más sobresalientes de resistencia máxima a la tensión (6.13 MPa), elongación máxima (82.83%) y módulo de elasticidad (243.06 MPa) se obtuvieron con una concentración de 0.75% y temperatura de 137.35°C. Se concluye que la adición de Tween 80 no afectó significativamente los valores en las propiedades estudiadas de las películas flexibles. Palabras clave: almidón termoplástico (TPS), ácido poliláctico (PLA), policaprolactona (PCL), Tween 80, película flexible Effect of the Additive Tween 80 and of the Process Temperature on the Mechanical Tensile Properties of Flexible Films Developed from Thermoplastic Cassava Starch AbstractThe aim of this research was to evaluate the effect of processing temperature and concentration of the additive Tween 80 on the mechanical tensile properties of a flexible film made of cassava thermoplastic starch (TPS), polylactic acid (PLA) and polycaprolactone (PCL). An experimental design was carried out to determine the temperature profile and Tween 80 concentration. Thereafter, treatment was chosen with the most outstanding results in mechanical properties and compared with a standard film (without Tween 80).The outstanding values of tensile strength (6.13 MPa), elongation (82.83%), and modulus of elasticity (243.06 MPa) were obtained with a concentration of 0.75% and temperature profile of 137.35 ° C. It is concluded that the addition of Tween 80 did not significantly affect the properties studied of the flexible films.