Polymer-modified aerogel samples were prepared by vacuum impregnation of silica aerogels with dimethylsiloxane-vinylmethylsiloxane copolymers. The specimens were characterized by H nuclear magnetic resonance (n.m.r.) relaxation measurements. The effects of the polymer molecular weight, irradiation and aerogel density upon the spin-lattice ( Tl ) and spin-spin ( T2 ) relaxation times were studied. Significant reduction was observed in the T2 values owing to increases in both aerogel and crosslink densities. H n.m.r. images reveal a high degree of heterogeneity in the samples. Distribution maps of the polymer-silica interactions and crosslink density are obtained.
Посилання на статтю:
Polymer distribution in silica aerogels impregnated with siloxanes by H nuclear magnetic resonance imaging / Leoncio Garrido*, Jerome L. Ackerman and James M. Vevea // Polymer. – 1992. – Vol 33. – P. 1826-1830.