Abundant, inexpensive, renewable, and nontoxic carbon dioxide (CO2) has become an attractive feedstock for chemical and polymer syntheses. The use of CO2 as a sustainable precursor for polyurethane has become prominent in polymer industry. In this study, polyols produced from CO2 were successfully incorporated into thermoplastic polyurethanes (TPUs). The thermal, mechanical, shape memory, and anticorrosion properties of the TPUs were investigated. TPUs with CO2-based polyols appeared as hard plastics with relatively high T g and tension set values. The rigid carbonate units of the CO2-based polyols reduced the softness of the polyol chains. The CO2-based polyols also afforded TPU with excellent shape memory characteristics, exhibiting shape fixity and shape recovery values of almost 100%. Interestingly, the incorporation of CO2-based polyols into TPUs improved the anticorrosion characteristics, regardless of the corrosive media. The improved anticorrosion characteristics stemmed from the robust, hydrophobic, and blocking properties of the carbonate units. This allows the TPU to be used in hard coatings for high-performance applications. CO2-based polyols are promising alternatives to conventional petroleum-based polyols and can be used for the fixation of waste CO2 and decreasing the carbon footprint of chemical processes.

Tetrabutylammonium carbonate (TBAC) which is obtained by treating CO 2 with tetrabutylammonium hydroxide is shown to perform as an ideal difunctional initiator for the copolymerization of carbon dioxide (CO 2) and propylene oxide (PO) in the presence of triethylborane (TEB). In this system, CO 2 thus serves as the initiating moiety of its own copolymerization with epoxides when used in the form of a carbonate salt. Based on this remarkable result, mono-, tri-, and tetrafunctional ammonium carboxylate initiators and also other difunctional carboxylate initiators were synthesized and used for the synthesis of well-defined ωhydroxyl-polycarbonates with linear and star structures. Well-defined telechelics, three-and four-armed star samples of molar mass varying from 1 kg/mol to 10 kg/mol, with around 95% carbonate content, were successfully synthesized. The structure of the obtained polycarbonate ω-polyols were characterized by 1 H NMR, MALDI-TOF, and GPC. The terminal hydroxyl functionality of polycarbonate diol was further used for polycondensation with diisocyanates to afford polyurethanes. Finally, taking TBAC as an example, the recyclability of this ammonium-based initiator is demonstrated for the preparation of polycarbonate diols. 65 polycarbonate diols and polyols eventually obtained under 66 these conditions are contaminated with monofunctional 67 chains, which is detrimental to the subsequent polycondensa-68 tion applications. As clearly demonstrated by Sugimoto et al., 69 polycarbonate tetrol and hexeol samples using

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A rapid and efficient method to remove thiocarbonylthio end groups from polymers prepared by reversible addition–fragmentation chain transfer (RAFT) is described. The elimination process is obtained in less than 1 min by treating the solution of RAFT-synthesized polymers with 5 equiv of trialkylborane (TAB) in the presence of oxygen under an ambient temperature. The versatility of this method was checked on the most relevant families of thiocarbonylthio chain transfer agents (CTA), including dithioesters, trithiocarbonates, dithiocarbamates, and xanthates, carried by the corresponding RAFT-synthesized polymers. UV, NMR, and MALDI-TOF MS characterization results all confirm the complete removal of their terminal CTA groups.

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Brush-type macromolecules (BMs) have attracted much attention over the past decades because of their unique properties and potential applications in nanoscience, drug-delivery systems, and photonics. A two-step strategy of synthesis of polycarbonate-grafted copolymers with either star-shaped or brush-typed morphologies using a “grafting from” approach is reported; the backbone in these all-polycarbonate graft copolymers is made of poly­(cyclohexene carbonate) (PCHC), and the side grafts are made of poly­(propylene carbonate) (PPC). In the first step, poly (vinyl-cyclohexene carbonate) (PVCHC) backbones of two different sizes (PVCHC35, PVCHC283) were prepared by copolymerization of vinyl-cyclohexene oxide (VCHO) with CO2 in the presence of triethylborane (TEB), using tetrabutyl ammonium succinate (TBAS) as the initiator. In the second step, the dangling vinyl double bonds of PVCHC were transformed into carboxylic acid groups. After partial neutralization of the latter using tetrabutyl ammonium hydroxide, the PPC grafts could be grown from the backbone carboxylic sites by copolymerization of propylene oxide (PO) with CO2 in the presence of TEB. Before attempting the synthesis of the above all-polycarbonate grafted copolymers, we check the viability of the above synthetic strategy by preparing graft copolymers made of a polymethacrylate backbone and PPC side grafts. In the latter case, the backbone was generated by reversible addition–fragmentation chain-transfer (RAFT) polymerization of methacrylic acid (MAA), followed by the growth of PPC side grafts using the backbone carboxylates as initiating sites. In both cases (PVCHC-g-PPC and PMAA-g-PPC), two types of architectures corresponding to two different morphologies were synthesized: star-shaped morphologies were obtained from rather short backbones, and relatively long grafts, on the one hand, and semiflexible cylinders were grown from rather long backbones and short grafts. These various structures were characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography/light scattering (GPC/LS), and their morphologies were further investigated by atomic force microscopy (AFM). The reported synthetic method provides a robust way to synthesize well-defined polycarbonates with either star-type or brush-type morphologies and graft copolymers made of polyacrylate backbones and polycarbonate grafts. Thermal and mechanical properties of these graft copolymers were also investigated.