Directly CO2-fixed, vegetable oil-based, and isocyanate-free polyhydroxyurethanes (PHUs) with relatively short chain lengths (Mn,SEC = 5.0−18.8 kg mol−1) were synthesized via aminolysis to enhance self-adhesion. The abundance of CO2-derived hydroxyl groups promoted strong intermolecular hydrogen bonding, forming a robust physical network that compensated for limited chain entanglement and enabled viscoelastic behavior. Bis(glycidyl ester) dimer acid was synthesized via one-pot glycidylation of dimer acid and epichlorohydrin, followed by CO2 bubbling to yield bis(cyclic carbonate) dimer acid (bisCCDA). Subsequent polyaddition with diamines produced PHUs containing 7−10 wt% CO2 and 67−91% biocarbon. These PHUs exhibited elastic-viscous properties with G′ > G″, and acetyl protection of hydroxyls significantly reduced mechanical performance, confirming the critical role of hydrogen bonding. Despite low molar mass, they showed pressure-sensitive adhesion (peel: 0.7−5.3 N cm−1; tack: 0.2−1.1 N; shear: 96−4000 min). The process also enabled partial recovery of raw materials, highlighting sustainability.