Fine structures of copolyesters containing naphthalene and 9,10-dihydrophenanthrene rings

✍ Scribed by Koichiro Yonetake; Hiroshi Yashiro; Mitsuru Ueda; Toru Masuko

• Book ID: 104164525
• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 442 KB
• Volume: 38
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/s0032-3861(96)00790-2

✦ Synopsis

Copolyesters composed of poly(ethylene 2,6-naphthalate) and poly(ethylene 9,10-dihydrophenanthrate) (PEN/PEHP copolymers) with different copolymer compositions were synthesized and their thermal properties and fine structures were investigated using thermal analysis and X-ray diffraction methods. TgS of the copolymers increased with increasing molar fraction of the PEHP component; on the other hand, their Tins decreased slightly and their crystallinity also decreased. The crystallites in the copolymers were assigned to the c~-or 8-polymorphic forms of PEN. In particular, annealed samples containing 5% and 10% PEHP exhibited X-ray diffraction patterns showing the coexistence of the c~-and i3-forms. In the case of samples containing 20% PEHP the crystallites were of the t3-form. Thus, the crystalites formed in the copolymers are composed of PEN sequences, while PEHP sequences remain in the amorphous regions. PEHP sequences interfere with the crystallization of PEN/PEHP copolymers and have a strong influence on the chain packing mode of the unit cell in the copolymers.