Browsing by Author "Arias Tapia, Mary Judith"

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Evaluación del fenómeno de die swell en mezclas de almidón de yuca y poly (ácido láctico) en el proceso de extrusión /
(2017) Arias Tapia, Mary Judith; Useche Vivero, Jairo
En este trabajo se estudió el comportamiento de las mezclas TPS/PLA y sus materiales constituyentes, utilizando la combinación de técnicas de simulación por Dinámica Molecular para caracterización reológica y modelado analítico y numérico, para estudio del comportamiento de los materiales en estudio durante el proceso de extrusión y el fenómeno de “die-swell”. Lo anterior, permitió profundizar en el conocimiento del comportamiento de los materiales alterativos, en este caso polímeros biodegradables que permitan reemplazar a los polímeros tradicionales provenientes del petróleo en aplicaciones específicas y que al final de su vida util, estos puedan ser biodegradados y de esta manera ayudar a reducir la contaminación por volumen. Además, la implementación de simulación, ayudaría en gran medida, a predecir el comportamiento de estos materiales, reduciendo costos y tiempo en la implementación de ensayos experimentales. Los resultados obtenidos, en este trabajo son una clara muestra que el nuevo campo de trabajo que se abre con los materiales biodegradables alternativos, esta aun por explorar, puesto que tanto los modelos como las técnicas de simulación están planteados para los materiales tradicionales provenientes del petróleo, lo que hace que se requieren ajustes en algunos parámetros, para poder entender de manera clara el comportamiento de los nuevos polímeros. Teniendo en cuenta lo anterior, se hace necesario aun, poder comparar con resultados experimentales, que permitan validar los resultados obtenidos por la simulación y los modelos utilizados.
Polylactic acid effectively reinforced with reduced graphitic oxide
(2022-09-01) De La Cruz Natera, Alejandra; Cordero García, Adriana; Restrepo Betancourt, Juan; Arias Tapia, Mary Judith
The present study was developed to reinforce a thermoplastic matrix with carbonaceous material to improve its thermal and mechanical properties. Composite materials formed from the homogenization of polylactic acid (PLA) and reduced graphitic oxide (RGO) were synthesized and characterized, reinforcement of the polymer's thermomechanical properties and the adequate homogeneity ratio in the dispersion of the composite material were studied. Graphitic oxide (GO) was synthesized by the modified Hummers method, followed by thermal exfoliation. The chemical composition and the structure of RGO were studied by infrared (FT-IR) and Raman spectroscopies, respectively. PLA composites with different RGO contents (2 and 3% by weight) were prepared and compared in terms of distribution of RGO in the matrix and morphology, using scanning electron microscopy. The thermal stability of the composites was determined through thermogravimetric analysis. Torque of the different composites was measured, which increased at 21%; the tensile test showed an improvement in the mechanical parameters of the composites because the RGO favors the rigidity of the composite. In addition, the oxygenated functional groups present in the RGO allowed a more significant interaction with the PLA matrix, which results in an effective reinforcement of the mechanical properties of the composite material
Thermal and Morphological Characterization of Native and Plasticized Starches of Sweet Potato (Ipomoea batatas) and Diamante Yam (Dioscorea rotundata)
(2020-09-18) Martinez Villadiego, Keydis; Arias Tapia, Mary Judith; Useche Vivero, Jairo; Ledesma, Yorleys; Leyton, Alexander
The objective of this study is to determine the morphological, physicochemical, and thermal properties of starches from two species of tubers, Ipomoea batatas (SP) and Dioscorea rotundata (DY), as well as the influence of glycerol as a plasticizer. The amylose/amylopectin content is 25.59/74.4 in DY; the granules are round and elliptical in shape with an average size of 25.5 μm, and the degradation temperature is 311.01 °C. The amylose/amylopectin content is 45.9/54.1 in SP; the granules are polygonal, oval, and semi-oval in shape with an average size of 9.5 μm, and the degradation temperature of 312.89 °C. The morphology of the granules in the different starch/glycerol formulations showed no structural damage to both species. However, increased degradation temperature was observed in the plasticized starches and in the shape and intensity of the band. Results indicate that the addition of glycerol improves the properties of native starches for processing and their potential use as bioplastics.
Thermoplastic Starch (TPS)/Polylactic Acid (PLA) Blending Methodologies: A Review
(2021-06-17) Martinez Villadiego, Keydis; Arias Tapia, Mary Judith; Useche Vivero, Jairo; Escobar Macías, Daniela
Polylactic acid (PLA) and thermoplastic starch (TPS) are biodegradable polymers of biological origin, and the mixture of these polymers has been studied due to the desirable mechanical properties of PLA and the low processing cost of TPS. However, the TPS/PLA combination is thermodynamically immiscible due to the poor interfacial interaction between the hydrophilic starch granules and the hydrophobic PLA. To overcome these limitations, researchers studied the modification, processing, and properties of the mixtures as a strategy to increase the compatibility between phases. This review highlights recent developments, current results, and trends in the field of TPS/PLA-based compounds during the last two decades, with the main focus of improving the adhesion between the two components. The TPS/PLA blends were classified as plasticized, compatible, reinforced and with nanocomposites. This article presents, based on published research, TPS/PLA combinations, considering different methods with significant improvements in mechanical properties, with promising developments for applications in food packaging and biomedicine