NUEVOS FLUIDOS ESTRUCTURADOS BASADOS EN MEZCLAS DE POLÍMEROS DENDRONIZADOS Y UN SURFACTANTE CATIÓNICO CAPAZ DE FORMAR MICELAS GUSANO

Dos nuevos polimeros dendronizados de diferente peso molecular (PLn) se sintetizaron a partir del acrilato de amina Behera. Resultados obtenidos por GPC y DLS indicaron que estos polimeros poseen una gran capacidad para formar agregados en solucion. No obstante, soluciones acuosas de PLn muestran un comportamiento reologico identico al agua incluso a concentraciones de 1000ppm. Su interaccion con un surfactante cationico, CTAT se estudio por reologia de corte simple en modos estacionario y oscilatorio. El PL1 mostro la mayor capacidad de interaccion con el CTAT a la maxima concentracion permitida antes de la separacion de fases (100ppm) obteniendose un aumento de un orden de magnitud en la viscosidad a bajas tasas de corte. La adicion de 100ppm de PL1 a una solucion de CTAT a 20mM conlleva a la formacion de un fluido altamente estructurado con un comportamiento reologico pseudoplastico. Mezclas de PL1/CTAT mostraron mayor elasticidad y tixotropia. La interaccion del PL2, el polimero con el mayor peso molecular teorico, con el CTAT produce un aumento extraordinario de la viscosidad al adicionar 0,25 ppm de polimero a la mezcla. Este efecto sinergistico solo es observado a bajas concentraciones de PL2 ocurriendo una saturacion a 25 ppm de polimero. Two new water soluble dendronized polymers (PLn) from acrylate Behera amine monomer of different molecular weights were successfully synthesized. GPC and DLS results indicated that these PLn have a remarkable tendency to form aggregates in solution. However, the addition of any PLn to water did not cause any increase in viscosity up to concentrations of 1000 ppm. The possible interactions of PLn with the cationic surfactant CTAT were explored by solution rheometry. The highest association tendency with CTAT was found for PL1 at the maximum polymer concentration before phase separation (i.e., 100 ppm). The solution viscosity at low shear rates could be increased by an order of magnitude upon addition of 100 ppm of PL1 to a 20 mM CTAT solution. The fluid obtained was highly structured and exhibited shear thinning behavior. PL1/CTAT mixtures exhibited an improved elastic character and a pronounced thixotropic behavior. In the case of the polymer with a higher theoretical molecular weight, PL2, its association with CTAT leads to an extraordinary doubling of solution viscosity with just 0.25 ppm polymer addition to a 20 mM CTAT solution. However, such synergistic viscosity enhancement saturated at rather low concentrations (25 ppm).