“…The peaks observed at three locations (f–d) are attributed to methyl (CH 3 , 2.42 ppm) and the benzene ring (7.30 ppm, 7.73 ppm) within the TSI fragment, respectively . Whereas PTHF exists as a flexible chain segment, the peaks at g and h denote the methylene group in the chain (CH 2 , 1.62 ppm) as well as the methylene group close to the oxygen (CH 2 , 3.44 ppm), respectively. , In addition, analysis by 13 C NMR (Figure S1) showed that, as the ring-opening copolymerization reaction between TSI and ECH proceeded, the signals at 62.74 ppm (the carbon atom that can be attributed to the terminal methylene group in PTHF) disappeared in the PU–PTHF–PU polymer, suggesting that all of PTHF was successfully linked to the PU chain segments. FTIR analysis further corroborated the polymer’s structural integrity, as illustrated in Figure B.…”