NEW NMR TOOLS FOR THE CHARACTERIZATION OF HYBRID SYSTEMS

This paper reports new methods recently developed in Si-29 NMR spectro scopy to investigate the structure of polymers which are formed by the polymerization of organo-alkoxysilanes. From DEFT polarization transf er experiments and two-dimensional Si-29-Si-29 INEPT DQF COSY, a large number of oligomers have been identified in these mixtures. Data on t heir quantitative distribution have allowed a better understanding of the influence of the hydrolysis ratio and the pH on the condensation r eactions.