Synthesis of Colorless and Transparent Poly(ether imide)s and Their PET Blends

Abstract

To replace Ultem (R), new poly(ether imide)s (PEIs) were synthesized using three types of diamine monomers: ethylenediamine, 1,4-diaminobutane, and 1,6-diaminohexane. On increasing the number of methylene groups in PEI structures, their thermal properties were deteriorated while their optical transparencies were improved. Among the three diamines, PEI containing 1,6-diaminohexane was blended with poly(ethylene terephthalate) (PET) in various concentrations by a solution blending method. To examine their properties, the blends were processed into films using a hot press. In PEI/PET blends, PET was not dispersed homogeneously in PEI at any concentrations tested. The thermal properties and optical transparency of the blends decreased with increasing PET contents, while the maximum enhancement in the mechanical property was observed at 25 wt% PET loading.