SELECTIVE LOCALIZATION OF CARBON NANOTUBES IN IMMISCIBLE BLENDS OF POLY(TRIMETHYLENE TEREPHTHALATE) AND ETHYLENE-VINYL ACETATE COPOLYMERS
碳纳米管在聚对苯二甲酸丙二酯/乙烯-醋酸乙烯酯共聚物不相容共混体系中的选择性分散

Poly(trimethylene terephthalate) (PTT) was melt-blended with ethylene-vinyl acetate copolymers (EVA) with the aim of enhancing toughness and plasticity of PTT.However,these two polymers were found to be thermodynamically immiscible and the formed blends showed deteriorated mechanical properties.The multi-walled carbon nanotubes (CNT) were thereby used to improve the phase morphology and adhesion of the PTT/EVA blend.The phase structures and rheology as well as mechanical properties were investigated by using scanning electron microscope (SEM),transmission electron microscope (TEM),contact angle measuring device and rotational rheometer respectively.A special selective localization of CNT could be observed on the ternary PTT/EVA/CNT composites.The CNT are selectively dispersed in the matrix PTT phase and the interface between two phases.This is due to the lower viscosity of PTT and its better affinity to CNT than those of the EVA.Thus,the CNT is more readily to be embedded by the PTT but not EVA during melt processing and finally,to be dispersed in the PTT phase and the interface.As a result of such selective localization,the size of EVA phase domains is reduced and the phase adhesion of the ternary composites is improved remarkably in contrast to those of the binary PTT/EVA blend.Therefore,the modulus and the plasticity of composites were enhanced.The CNT are believed to act as the compatibilizer and the plasticizer in the immiscible PTT/EVA blend.