Effect of tertiary polysiloxane on the phase separation and properties of epoxy/PEIblend

摘要

Epoxy functional siloxane (DMS-E09) was blended with epoxy resin (DGEBA) and thermoplastic polyetherimide (PEI). The results of morphology monitoring indicated that the reaction induced phase separation for all blends followed the spinodal phase separation mechanism. The microstructure changed from co-continuous of 25 wt% epoxy/PEI system to phase-inversion structure of 30 wt% epoxy/PEI system regardless of the content of the tertiary component DMS-E09. By comparing the onset time of phase separation between the two designated systems, the sequential occurrence of primary macrophase separation in co-continuous phase and secondary microphase separation in PEI-rich phase for 25 wt% epoxy/PEI system was identified. Studies of the thermomechanical properties of the DGEBA/PEI/DMS-E09 blends found that storage modulus increased with the addition of PEI but decreased with DMS-E09 monotonically. The value ofT(g)decreased with the addition of the tertiary DMS-E09 but was offset partially by the presence of PEI.