Tan-delta plateau in vitrimer-like polyurethanes

Abstract

• Tan delta plateau (TDP) over a long temperature range is revealed in a vitrimer-like polyurethane. • The TDP is rather stable at different frequencies and oscillation strains. • Gradual dissociation right after melting is identified as the reason for TDP. • The time–temperature equivalence of the dissociation process is confirmed. A vitrimer-like polyurethane is investigated for its Tan-delta plateau phenomenon (i.e., a quasi-steady high Tan-delta value over a long temperature range). It is concluded that this plateau is associated with cross-linking dissociation, but on the condition that this dissociation process should be over a long temperature range and right after a melting transition. While this plateau is rather stable at different oscillation strains and frequencies, the time–temperature equivalence of the dissociation process is confirmed to be applicable to this material.