Phase I and II crystals of poly(p-oxybenzoate). I. Effects of substrate and melt polymerization conditions

✍ Scribed by F. Rybnikar; P. Saha; B.-L. Yuan; P. H. Geil

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 273 KB
• Volume: 37
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19991215)37:24<3520::aid-polb13>3.0.co;2-1

✦ Synopsis

Acid and base treatment of glass and mica substrates affects the phase II/I crystal structure ratio of poly(p-oxybenzoic acid) polymerized by the confined thin film melt polymerization (CTFMP) technique; acid treatment of mica enhances the phase I content, whereas base treatment of glass and mica results in growth of 100% phase II crystals. In bulk melt polymerized samples, without added catalyst, the fraction of phase II increases with increasing polymerization temperature, up to 25-30% above 300 °C; this is suggested to be related to a "PH phase" (pseudo-hexagonal), consisting of 3 pairs of phase I and II crystals, rotated by 60°, in CTFMP samples annealed above their T k-m . The addition of a base to the polymerization system also results in an increase in the phase II content, up to almost 100% in some cases. The effect of the addition of base is tentatively attributed to a change in the alignment of neighboring molecules growing out from the initial nucleus during the simultaneous polymerization (liquid crystal) crystallization.