Rubber-modified cyanate esters: thermodynamic analysis of phase separation

摘要: Abstract Cloud-point curves were determined for blends of a rubber (butadiene—acrylonitrile random copolymer terminated in non-functional groups, NFBN) and cyanate ester (4,4′-dicyanate-1,1′-diphenylethane, CE). Measurements made the initial blend partially polycondensed (thermal polycyclotrimerization CE monomer). conversions temperatures different fractions formulation. A thermodynamic analysis based on Flory-Huggins equation, taking polydispersity both components into account, led to following conclusions. (1) Phase separation was result change two contributions free energy mixing: (a) decrease entropic contribution due increase oligomer size; (b) enthalpic as cohesive density CE-oligomer course polycondensation. (2) Spinodal demixing excluded possible mechanism phase during polycondensation solutions containing less than 12% by volume.