Hybrid Cyclic Carbonate as a Thermally Reversible Hot Melt Adhesive‐ Synthesis and Characterization

Abstract A hybrid cyclic carbonate (HCC) with multiple functionalities has been synthesized via the reaction of CO 2 with an epoxy monomer under moderate pressure and temperature, which can act as a robust single‐component, thermoreversible adhesive to a variety of substrates. The adhesive feature has been attributed to the combined presence of epoxy, hydroxyl, and cyclic carbonate functionalities in the HCC capable of forming reversible hydrogen‐bonding interactions, as confirmed through FTIR and 1 H NMR spectroscopic techniques. The synthesized HCC, containing 70% cyclic carbonate content, has been examined for its thermo‐reversibility for adhesion, using temperature‐dependent FTIR, temperature‐dependent 1 H NMR, hot‐stage polarized light microscopy (PLM), and rheological studies. The HCC exhibited favourable lap shear strength of 4.5 ± 0.34 MPa for Al–Al, 2.6 ± 0.42 MPa for steel–steel, 2.2 ± 0.29 MPa for HDPE–HDPE, and 1.6 ± 0.33 MPa for Teflon–Teflon substrates. The thermo‐reversible behavior has been further investigated using Density functional theory (DFT) calculations, which confirm that the reversible adhesion arises from the formation of multiple hydrogen‐bonding interactions. Differential scanning calorimetric (DSC) analysis revealed a glass transition temperature (Tg) of 20°C, while significant thermal degradation was observed above 400°C for the developed system.