The crude polymers were fully characterized by 1 H NMR spectroscopy and size exclusion chromatography. NMR spectroscopy was used to calculate the final CC conversion, which was further used to estimate the molecular weight of the polymer according to the Carothers equation. The (OH)I : (OH)II ratio were also calculated based on the NMR spectrum. The number average molar masses, Mn, and the dispersity, Ð, of the polymers were estimated via SEC measurements. The glass transition temperature, Tg, of the polymers and the heat capacity difference at Tg, ∆Cp, were measured by dynamic scanning calorimetry (DSC). Finally, their degradation temperature, Td5% (temperature at 5wt% loss) were measured by thermogravimetric analysis (TGA). The results are listed in Table . The characteristics of poly(EA1) can be compared with the data reported by Schmidt et al. for the one-step synthesis of PHUs obtained by polyaddition of EDC in solvent. They reacted EDC, in DMSO (1 mol L -1 ), with 1 eq. of A1 at 100 °C (20 h). The 1 H NMR analysis indicate that MNMR = 14 800 g mol -1 and (OH)I : (OH)II = 34 : 66. Thus, MNMR is similar to the value measured for our polymer, poly(EA1). The (OH)I : (OH)II ratio is very different from ours and this might be due to the above-mentioned difference in the assignment of the NMR signals. The Tg of the polymer obtained via the one-step protocol of Schmidt et al. is also much smaller, Tg = 9 °C against 52 °C for poly(EA1). This might be due to the presence of residual DMSO in their polymer, or a consequence of significant structural discrepancies between our polymers due to the difference of our respective polymerization protocols. 60 for poly(TA1) and poly(TA2) respectively. Again, the regioselectivity is in close agreement with the results obtained previously for the model reaction of TDC with HA. It is not impacted by the chain insertion process during the polyaddition reaction, suggesting that it is possible to synthesize PHUs with tunable regioregularity simply by tuning the stereochemistry of the vicinal dicarbonate. Indeed, the content of primary hydroxyl group is significantly increased when using TDC, the (S,S) stereoisomer, instead of EDC, its (S,R) diastereoisomer. With 85% of secondary hydroxyl groups, against 60% for the PHUs derived from TDC, The PHU derived from EDC exhibits a higher degree of regioregularity. The DSC thermograms of poly(TA1) and poly(TA2) are plotted in Figure . When compared to the thermograms of poly(EA1) and poly(EA2), the most remarkable difference is that, the heat capacity difference at Tg, i.e. the difference of heat capacity between the glassy and the liquid state, ∆Cp, is much smaller in the case of poly(TA1) and poly(TA2). The regioregularity of the PHUs being directly connected to the stereochemistry of the vicinal dicarbonates, our result suggest that it is possible, to some extent, to tune the thermal properties of PHUs by controlling the stereochemistry of the dicarbonates.