A vinyl ether containing a five-membered cyclic carbonate group, 2-(2-vinyloxyethoxy)ethyl carbonate (VEECN), was synthesized by adding CO2 to 2-(2-vinyloxyethoxy)ethyl glycidyl ether, which is a vinyl ether containing an epoxy group. Cationic polymerization of VEECN was performed in nitromethane at − 30 °C with boron trifluoride etherate. The resulting poly(VEECN) exhibited a number-average molecular weight of ~ 3500 g/mol and a molecular weight distribution of ~ 1.40. Poly[2-(2-vinyloxyethoxy)ethyl hydroxyurethane]s [poly(VEEHU)-C2 to -C5] were synthesized by reacting the cyclic carbonates in the side chains of the obtained poly(VEECN) with four alkanolamines with different methylene numbers (2–5) to form hydroxyurethane groups. The reaction ratios were adjusted to approximately 50%, 75%, and 100%, and the thermal responses and properties of poly(VEEHU)-C2 to -C5 were investigated. When the urethanization ratio was ~ 50%, the cloud points (Tcp) of 1% w/v poly(VEEHU)-C3 to -C5 aqueous solutions were observed at 46, 27, and 8 °C, respectively, with the temperature decreasing with increasing methylene number. Conversely, the poly(VEEHU)-C2 aqueous solution did not exhibit a Tcp at ≤ 95 °C. The glass transition temperatures of the polymers were − 32 °C for poly(VEECN) and − 28, − 32, − 33, and − 35 °C for poly(VEEHU)-C2 to -C5, respectively. Additionally, the thermal decomposition temperatures of the polymers were 279 °C for poly(VEECN) and 253–262 °C for poly(VEEHU)-C2 to -C5, indicating that poly(VEEHU) were flexible polymers at room temperature with relatively high thermal stabilities. [ABSTRACT FROM AUTHOR]