PREPARACIÓN Y EVALUACIÓN DE COMPATIBILIZANTES PARA MEZCLAS DE POLIESTIRENO/SILICONA Y CAUCHO NATURAL/SILICONA
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Universidad Industrial de Santander
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Se presentan los resultados experimentales de una investigación realizada para preparar copolímeros de bloque y de injerto del tipo poliestireno-silicona (PS-b-PDMS) y caucho natural-silicona (NR-g-PDMS), utilizando mecanismos de copolimerización por radicales libres. Estos copolímeros fueron caracterizados y evaluados como aditivos de compatibilización de mezclas inmiscibles poliestireno/silicona y caucho natural/silicona en proporción 50/50. La evaluación se realizó haciendo un seguimiento del comportamiento mecánico de dichas mezclas con diferentes porcentajes de aditivo sintetizado y comparando con los mismos sistemas pero sin adicionar el compatibilizante. Los resultados mostraron que bajos porcentajes de adición de copolímero, del 5% al 10%, mejoran la resistencia tensil y la dureza de las mezclas y se consigue un efecto sinérgico con las propiedades de los respectivos homopolímeros mezclados. La compatibilidad alcanzada fue resultado de la reducción de tamaño de las fases dispersas, detectada por microfotografía.
Block and graft copolymers of the type polystyrene-b-poly (dimethylsiloxane) and natural rubber-g-poly (d¡methylsiloxane), were synthesized by using a free-radical polymerization mechanism. These copolymers were characterized and evaluated as compatibilizers for non-miscible blends of polystyrene/poly (dimethyisiloxane) and natural rubber/poly (dimethylsiloxane) both with a mass ratio of 50/50. The evaluation was carried out by following the mechanical behavior of the blends prepared with different percentages of compatibilizer added and comparing with the same systems without additive. The results indicated that low additions (5%-10%) of the synthesized copolymers increase tensile strength and hardness of the blends with a synergistic effect between the properties of the respective homopolymers in the blends. A good degree of morphological compatibilization was observed in thin films by optical microscopy of light transmission as a consequence of the size reduction in the dispersed microphases.
Block and graft copolymers of the type polystyrene-b-poly (dimethylsiloxane) and natural rubber-g-poly (d¡methylsiloxane), were synthesized by using a free-radical polymerization mechanism. These copolymers were characterized and evaluated as compatibilizers for non-miscible blends of polystyrene/poly (dimethyisiloxane) and natural rubber/poly (dimethylsiloxane) both with a mass ratio of 50/50. The evaluation was carried out by following the mechanical behavior of the blends prepared with different percentages of compatibilizer added and comparing with the same systems without additive. The results indicated that low additions (5%-10%) of the synthesized copolymers increase tensile strength and hardness of the blends with a synergistic effect between the properties of the respective homopolymers in the blends. A good degree of morphological compatibilization was observed in thin films by optical microscopy of light transmission as a consequence of the size reduction in the dispersed microphases.