END-GROUP ANALYSIS OF POLY(PHENYL GLYCIDYL ETHER) .1. HYDROXYLIC GROUPS USING H-1 AND C-13 NUCLEAR-MAGNETIC-RESONANCE

The hydroxylic end-groups in the soluble fraction of poly(phenyl glyci dyl ether) (PPGE) obtained with the aluminium isopropoxide (AIP)/ZnCl2 initiator system are studied using nuclear magnetic resonance spectro scopy (NMR). To achieve complete assignment, model compounds are synth esized and their carbamate and trifluoroacetate derivatives obtained f rom trichloroacetyl isocyanate (TAI) and trifluoroacetic anhydride (TF AA) are prepared. These derivatizating reagents allow primary and seco ndary alcohols to be distinguished, since upfield or downfield shifts are produced, and at the same time they have the potential of separati ng overlapping peaks. Several PPGEs with different degrees of regulari ty are also synthesized using various initiator systems. Thus, it is p ossible to identify the carbon signals of both final hydroxylic groups and their adjacent units, and the presence of two types of unit linke d to secondary hydroxylic end-groups is demonstrated. Likewise, in the soluble fraction prepared with AIP/ZnCl2 the absence of the irregular units linked to secondary hydroxylic end-group is demonstrated, so pr oving the high regularity of this fraction.