A wholly aromatic copolyester having an ordered comonomer sequence was prepared from 2,7- naphthalenediyl bis(4-hydroxybenzoate) and terephthalic acid following a method reported previously This polymer was subjected to thermal treatment at 305°C under nitrogen atmosphere and the sequence randomization process was quantitatively analysed by 13C n.m.r, spectroscopy The melting temperature of the original polymer was 290°C. According to the results of analysis for various triad formation, the ester bonds in the triad of terephthaloyl-p-oxybenzoyl-oxynaphthyleneoxy (TPN) sequence were found to undergo very fast exchange reactions at the treatment temperature. The formation of PPP triad was evident after 30 min at 305°C, whereas PP dyad was formed after only 10 min. Although the sequence' changes occurred rather rapidly, complete randomization was not attained even after 1 h
Посилання на статтю:
Thermal sequence randomization of a wholly aromatic copolyester having an ordered sequence / Jung-II Jin // Polymer. – 1992. – Vol 33. – P. 1374-1378.