Study on the Phase Separation of PET/PEN Blend by Dynamic Rheology

摘要

By examining viscoelastic functions of poly (ethylene terephthalate)/ poly (ethylene naphthalate) blends, we found that the departure of classic viscoelasticity happened in low frequency. The relationships between dynamic storage moduli G'(or dynamic loss moduli G") vs. frequency lgG'～lgωαT (or lgG"～lgωαT) depart from classic viscoelastic model. Time-temperature superposition (TTS) theory was inducted in studying the phase-separation phenomenon of PET/PEN blends system. It is interesting that the breakdown of TTS depends on components. The lgG'～lgωαT curve is more sensitive than lgG"～lgωαT curve. Results indicate: PET/PEN blends system is a kind of micro separate phase material. The primary reason of why the barrier properties of PET/PEN blends are better than that of PET is the lamellar structure formed after bi-oriented. But block copolymer produce by the transesterification reaction during PET and PEN blend process change the separation of PET and PEN illegibility so DSC can not examine the separation of PET/PEN blends.