Polymorphism of poly[bis(p-methoxyphenoxy)phosphazene]

✍ Scribed by Tadakazu Miyata; Toru Masuko; Morio Kojima; Joseph H. Magill

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 597 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950123

✦ Synopsis

Abstract

Well characterized poly[bis(p‐methoxyphenoxy)phosphazene] (PB(4‐MeO)PP) has been investigated employing X‐ray diffraction and differential scanning calorimetry (DSC). The DSC heating scan of the original PB(4‐MeO)PP specimen exhibits one exotherm at 110°C and two endotherms at 106°C and 126°C, respectively. Only a single endotherm at 131°C appears on the second heating. X‐ray diffraction measurements at elevated temperature reveal that PB(4‐MeO)PP crystal is monoclinic (β‐form) with unit cell dimensions a = 2,47 nm, b = 1,98 nm, c = 0,983 nm and y = 102° in the range of 106–126°C. Initially PB(4‐MeO)PP specimens are observed to be orthorhombic (α‐form) with a = 2,39 nm, b = 1,79 nm and c = 0,983 nm. The crystal transforms at 106°C and then changes into the β‐form at 110°C according to DSC measurements. At 126°C the β‐form crystal changes into a mesophase with an intermolecular distance of 1,44 nm at 150°C. The 3‐dimensional orthorhombic γ‐form with a = 2,21 nm, b = 2,01 nm and c = 0,963 nm is found at room temperature after specimens are cooled through T(1) = 126°C from the mesophase.