SYNTHESIS AND CHARACTERIZATION OF POLY(OXYETHYLENE)S WITH (2-BENZOXAZOLON-3-YL)ACETYL END-GROUPS - COMPLEX-FORMATION WITH POLYCARBOXYLIC ACIDS

Chemical modification of poly(oxyethylene)s (MW from 600 Da to 3000 Da ), leading to the obtaining of poly(oxyethylene)s with (2-benzoxazolon -3-yl)acetyl endgroups, is described. The corresponding diesters were synthesized in high yields-70-84% and degree of esterification-82-92% under mild conditions in the presence of dicyclohexylcarbodiimide and 4-dimethylaminopyridine as catalyst. The diesters were characterized b y H-1-NMR, C-13-NMR and IR spectra, and SEC analysis. The relatively n arrow molecular weight distribution was retained in the process of che mical modification. The complex formation between polyacrylic or polym ethacrylic acids and (2-benzoxazolon-3-yl)acetyl derivatives of poly(o xyethylene)s was studied in dilute aqueous solutions by potentiometric titration and viscometry. The presence of (2-benzoxazolon-3-yl)acetyl end groups attached to the poly(oxyethylene)s chains results in a sig nificant decrease of the critical poly(oxyethylene) chain length neces sary for the formation of stable polymer-polymer complexes.