Synthesis and Properties of Networks Based on Thiol-ene Chemistry Using a CO₂ -Based δ-Lactone

3-Ethylidene-6-vinyltetrahydro-2H-pyran-2-one, a divinyl δ-lactone derived from CO₂ and 1,3-butadiene, is used for the synthesis of networks with various compositions through the thiol-ene click reaction with di- and tri-thiol compounds. Thermal, mechanical, and optical properties of the networks are characterized. The networks have sharp and uniform glass transitions and show good thermal stability with T _d from 287 to 332 °C. Mechanical properties of the networks can be adjusted by the cross-link density; 6.18 MPa of tensile strength, 574% break elongation and 1.84 of tan δ at maximum are reached. Metal complexation makes the networks tougher due to additional cross-links. The highly homogeneous networks are transparent with average 90% transmittance of visible light, and of decent refractive indices around 1.55. Swelling-induced twist shape transformation and visible QR code under UV light is realized by pattern of the network.