By integrating phase transition theory and Takayanagi principle, we have developed a thermodynamic model to describe working mechanism and thermomechanical behavior of shape memory polymers (SMPs) with tunable multi-shape memory effect (multi-SME). Thermodynamics and state/phase transitions of different segments in the SMPs were modeled by considering their cooperative relaxation, which is defined as a process where a group of segments undergo relaxation simultaneously, based on the Takayanagi

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... rinciple. Dependences of thermomechanical behavior of amorphous polymers on volume fraction, cooperative relaxation and glass transition temperatures of both hard and soft segments were theoretically investigated. Working mechanisms of the multi-SME and cooperative relaxation of the amorphous polymers have well been explained using this newly proposed model, which offers an effective approach for designing new SMPs with multi-segments.