Polyurethane-prepolymerized isocyanate

In this polyurethane-prepolymerized isocyanate reaction, the fastest catalyst are the acetylacetonate complexes. Looking at the molecular structures involved, an octoate is a 2-ethylhexoate, having the structure... 

To contain the magnetic particles, the base polymer must be crosslinked. In this study, the polyurethane reacts with a prepolymerized isocyanate. There is a question as to the exact site where the isocyanate reacts. Isocyanate reacts with an "active hydrogen" on a compound as in the following example ... 

Weisfeld s order of reactivity is directly opposed to the order studied in this work, although the same test method was used in both experiments. Weisfeld used monomeric isocyanate and polyester while this study included carboxyl terminated polyurethane and prepolymerized isocyanate.(5) This distinction between monomeric and polymeric materials could explain the distinct contrast in catalytic activity. 

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