Relationship between morphology and glass transition temperature in solvent-crystallized poly(aryl ether ketones)

✍ Scribed by D. S. Kalika; D. G. Gibson; D. J. Quiram; R. A. Register

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 159 KB
• Volume: 36
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19980115)36:1<65::aid-polb8>3.0.co;2-t

✦ Synopsis

The relationship between semicrystalline morphology and glass transition temperature has been investigated for solvent-crystallized poly(ether ether ketone) (PEEK) and poly(ether ketone ketone) (PEKK). Solvent-crystallized specimens of both PEEK and PEKK displayed a sizeable positive offset in T g compared to quenched amorphous specimens as well as thermally crystallized specimens of comparable bulk crystallinity; the offset in T g for the crystallized samples reflected the degree of constraint imposed on the amorphous segments by the crystallites. Small-angle X-ray scattering studies revealed markedly smaller crystal long periods ( d) for the solventcrystallized specimens compared to samples prepared by direct cold crystallization. The strong inverse correlation observed between T g and interlamellar amorphous thickness ( l A ) based on a simple two-phase model was in excellent agreement with data reported previously for PEEK, and indicated the existence of a unique relationship between glass transition temperature and morphology in these poly(aryl ether ketones) over a wider range of sample preparation history and lamellar structure than was previously reported.