Abstract:Quaternary ammonium-containing star-shaped polylactic acid (PLA-Q) is analyzed in melt rheology and found to follow a clustering behavior. The viscosity of this polymer is largely higher than its analog, of the same structure, without ammonium ions. This difference is attributed to physical interactions taking place between the ammoniums and hindering the flow of the melt polymer. The frequency sweeps of the storage (G 0 ) and loss (G 00 ) modulus of the melt PLA-Q are achieved at different temperatures and di… Show more
“…By plotting as a function of , a linear relation was found (R 2 = 0.98), as shown in Figure 2 E. This result confirms the Arrhenius behavior and allows the determination of E a from the slope of the line; it is found to be equal to 90.1 kJ mol −1 . This value is in accordance with those found in the literature and corresponding to such interactions (ionic weak interactions) [ 54 , 55 , 56 ].…”
Antimicrobial textile structures are developed based on polypropylene (PP) and a natural material, hydrolyzed casein. The casein, from bovine milk, is subjected to acid hydrolysis in aqueous media, then blended into the PP matrix in the melt phase by extrusion. The obtained blend, containing 5 wt.% of hydrolyzed casein, is then processed by a melt spinning process to get multifilaments, leading to the production knitting structures. Thanks to the addition of the hydrolyzed casein, the obtained textile showed a strong antibacterial activity towards both Gram (+) and Gram (−) bacterial strains. The addition of 5 wt.% hydrolyzed casein does not significantly impact the mechanical properties of PP in the dumbbells form, but a small decrease was observed in the tenacity of the filaments. No moisture retention was observed after the addition of hydrolyzed casein, but the rheological behavior was slightly affected. The obtained results can contribute to addressing concerns regarding nonrenewable antibacterial agents used in textile materials, particularly their effects on the environment and human health, by offering antibacterial agents from a biobased and edible substance with high efficiency. They are also promising to respond to issues of wasting dairy products and recycling them, in addition to the advantages of using melt processes.
“…By plotting as a function of , a linear relation was found (R 2 = 0.98), as shown in Figure 2 E. This result confirms the Arrhenius behavior and allows the determination of E a from the slope of the line; it is found to be equal to 90.1 kJ mol −1 . This value is in accordance with those found in the literature and corresponding to such interactions (ionic weak interactions) [ 54 , 55 , 56 ].…”
Antimicrobial textile structures are developed based on polypropylene (PP) and a natural material, hydrolyzed casein. The casein, from bovine milk, is subjected to acid hydrolysis in aqueous media, then blended into the PP matrix in the melt phase by extrusion. The obtained blend, containing 5 wt.% of hydrolyzed casein, is then processed by a melt spinning process to get multifilaments, leading to the production knitting structures. Thanks to the addition of the hydrolyzed casein, the obtained textile showed a strong antibacterial activity towards both Gram (+) and Gram (−) bacterial strains. The addition of 5 wt.% hydrolyzed casein does not significantly impact the mechanical properties of PP in the dumbbells form, but a small decrease was observed in the tenacity of the filaments. No moisture retention was observed after the addition of hydrolyzed casein, but the rheological behavior was slightly affected. The obtained results can contribute to addressing concerns regarding nonrenewable antibacterial agents used in textile materials, particularly their effects on the environment and human health, by offering antibacterial agents from a biobased and edible substance with high efficiency. They are also promising to respond to issues of wasting dairy products and recycling them, in addition to the advantages of using melt processes.
“…Se observa cómo el tiempo de relajación es menor cuanto mayor es la temperatura del ensayo. Como se ha comentado con anterioridad, esto es debido a que cuanto mayor es la temperatura, más débiles son las interacciones de van der Waals que unen las cadenas poliméricas, de manera que el movimiento entre cadenas se facilita, aumentando así la capacidad de fluir del material, lo que se traduce en un tiempo de relajación inferior [327].…”
Con esta tesis dejo constancia, por escrito, desde hoy y para la prosperidad, del amor que siento por la ciencia, por el continuo crecimiento, por el enseñar y por el aprender, por el escuchar y por el ser escuchado, por la infinita creencia de que las cosas se pueden hacer mejor, de que se puede ser mejor y de que rodeado de la compañía correcta, todo es mejor.A mi director el Dr. José Sanes Molina, por ser un ejemplo del camino a seguir, habiendo dedicado una vida a la ciencia y la enseñanza. Gracias, por tu apoyo, tu sinceridad, tu constancia, tu buen hacer, cada uno de tus consejos y, sobre todo, cada una de las horas que has dedicado a ayudarme, en todo cuanto he necesitado. Gracias.Se ha observado que todos los líquidos iónicos y todos los nanofluidos utilizados reducen el coeficiente de fricción y el daño superficial cuando se utilizan como lubricantes externos sobre el polímero. Cuando se utilizan como lubricantes internos se observa que los líquidos iónicos apróticos que contienen el anión hexafluorofosfato no mejoran las propiedades tribológicas del polímero ni reducen el daño superficial. En cambio, tanto los líquidos iónicos apróticos que contienen el anión tetrafluoroborato, como el líquido iónico prótico y el nanofluido preparado a partir del líquido iónico prótico con óxido de zinc reducen notablemente el coeficiente de fricción de la matriz polimérica y el daño superficial.
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