LC-polyimides XXXIV. Noncrystalline thermotropic copoly(ester-imide)s based on PET
✍ Scribed by Hans R. Kricheldorf; Andreas Gerken; Heli Karhinen
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 201 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
Four series of copoly(ester-imide)s (co-PEIs) were prepared by transesterification of poly(ethylene terephthalate), PET, with N-(4-carboxyphenyl)trimellitimide and an acetylated diphenol. Methylhydroquinone, tert. butylhydroquinone, phenylhydroquinone, and 2,7-dihydroxynaphthalene were used as diphenols. The chemical structures of these co-PEIs were characterized by chemical analyses, 1 H-, and 13 C-NMR spectra. A low degree of crystallinity was observed when the PET content was above 85% mol %. Between 60 and 80 mol % PET all co-PEIs are biphasic, whereas below 60 mol % the co-PEIs form a homogeneous nematic melt and below the glass transition temperature ( T g ) a nematic glass. The T g s vary continously with the molar composition but the mechanical properties drop sharply when the nematic phase changes to an isotropic one.