1. Structure development in polyurethane networks based on star-like precursors
- Author
-
Karel Dušek, P. Vlasak, and Miroslava Dušková-Smrčková
- Subjects
Chemistry ,Star (game theory) ,Concentration effect ,Surfaces and Interfaces ,General Chemistry ,Critical ratio ,Oligomer ,Surfaces, Coatings and Films ,Dilution ,Crystallography ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Molar ratio ,Polymer chemistry ,Polyurethane - Abstract
A network formation from an OH-functional star oligomer and two isocyanates (HDI and HDI-trimer) was investigated by changes in the critical molar ratio of OH groups $$(r_{\rm OH})_{\rm c}$$ as a function of dilution. The critical ratio $$(r_{\rm OH})_{\rm c}$$ is such critical excess of OH groups at which the critical conversion of NCO at the gel point groups reaches 100%. The dilution effect was interpreted by pronounced cyclization, which was higher in the case of the HDI-trimer compared with the HDI.
- Published
- 2007