Chemorheology of polyurethane. I. Vitrification and gelation studies

We propose in this article a study of the viscoelastic behavior of reticulated PU systems that are synthesized from a triisocyanate and a polyetherdiol of molar mass 1000 or 2000 g · mol−1. We initially sought to confirm the expected results concerning the phenomenon of gelation, and in particular, that the power law G′ ∼ G″ ∼ ωΔ is verified. The appearance of a maximum of tan δ on the rheological curves led us to consider a second state of transition, namely vitrification. This could constitute an invaluable source of information on the complex morphology of the final material due to the microheterophased character of PU.