Influence Of Tertiary Component On Cure-Reaction-Induced Phase Separation In Thermoplastics/Epoxy Blends

The influence of attapulgites (ATTs) on cure-reaction-induced phase separation in epoxy/poly(ether sulfone) (PES) blends and the influence of epoxidized butadiene-styrene diblock copolymer(EBS) in epoxy/poly(phenylene oxide) (PPO) blends have been studied with optical microscopy(OM), time-resolved light scattering(TRLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic mechanical analysis(DMA).In the ATT/PES/Epoxy blends, the SEM results show that the incorporation of a small amount of ATT into the blends can change the final phase morphology markedly and affect the secondary phase separation. The TEM results show that ATT particles are well separated in the blend and during the phase separation the ATT particles are pinned down at the phase interfaces by the interfacial tension. The results of TRLS and OM show that, the pinned ATT particles along the interface slow the interfacial motion and decrease the size of the both phase domains. In addition, the incorporation of a small amount of ATT particles can improve the modulus and tensile strength because of the increased interfacial interaction of the PES-rich and epoxy-rich phases.In the EBS/PPO/Epoxy blends, two kinds of EBS with different epoxidation degree show different modification results. For the low epoxidized EBS, with certain concentration, the epoxidized polybutadiene block separates from the epoxy-rich phase and formes the nano-size fibers. And in the blends with higher concentration of EBS, the EBS would separate from the matrix and form macro-phase domains. For the high epoxidized EBS, the solubility of which in epoxy is much better, the two blocks would dissolve in the two macro-phases separately according to the selectivity. So the phase evolution process is retarded markedly, which make the blends with a wide range of PPO concentration form the bi-continuous phase morphology.