Shape memory behavior was analyzed by fastening a tensile test dogbone specimen into a dynamic mechanical analysis device equipped with a tensile test sample bracket. The sample was heated to 140 °C with a heating rate of 20 °C min -1 and, after an equilibration period, strained by 50% based on the length of the parallel section of the specimen. The sample was air-cooled to room temperature using a cooling rate of 5 °C min -1 . The strain previously applied by the measurement device was removed to test the ensuing contraction of the sample (shape fixity). Next, the sample was heated to 140 °C again with a heating rate of 10 °C min -1 under no external stress and held at this temperature for 70 min. The contraction of the sample during this process was recorded and divided by the sample strain after it was allowed to contract to calculate the shape recovery. This process was repeated up to 10 times during one measurement. The equations used to calculate shape fixity and shape recovery are given in the Supplementary Information (Supplementary Equations 3 and 4).