Hydroxytelechelic polybutadiene, 14. Gelation of a radically obtained hydroxytelechelic polybutadiene with 4,4′-methylenedi(phenyl isocyanate)

A new commercial radically obtained hydroxytelechelic polybutadiene (HTPB-A) was examined by ¹H NMR at 500 MHz, and a corrected interpretation of the complex proton methylene resonance of the vinyl-type primary alcohol was done. The weight-average hydroxyl functionality F?_w (OH) was determined by using critical conversions at gel points of the (HTPB-A + diisocyanate) systems, on the one hand, and swelling at equilibrium on the other. The functionality polydispersity index of HTPB-A is close to unity.