Fixation of carbon dioxide concurrently or in tandem with free radical polymerization for highly transparent polyacrylates with specific UV absorption

It is still a challenging issue to combine the coupling reaction and free radical polymerization (FRP) for well-controlled and efficient synthesis of polyacrylates bearing the cyclic carbonate group from carbon dioxide (CO2) and vinyl epoxides. This work describes the efficient catalytic synthesis of poly(2-oxo-1,3-dioxolane-4-yl)methyl methacrylate (PDOMA) from CO2 and glycidyl methacrylate (GMA) via concurrent or tandem combination of the coupling reaction and FRP. In a concurrent reaction, GMA/CO2 coupling with 100% oxirane conversion was achieved by using a nanolamellar zinc–cobalt(III) double metal cyanide complex [Zn–Co(III) DMCC] (0.30 mol% Zn related to GMA) with cetyltrimethylammonium bromide (CTAB) (0.65 mol% related to GMA) as the catalyst, and PDOMA was obtained via the concurrent free radical polymerization of carbon–carbon double bonds in the presence or absence of additional free radical initiator. In the tandem process, (2-oxo-1,3-dioxolane-4-yl)methyl methacrylate (DOMA) was firstly synthesized via GMA/CO2 coupling catalyzed by Zn–Co(III) DMCC/CTAB and purified by simply passing through a basic aluminum oxide column. DOMA could be polymerized via solution or emulsion polymerization, leading to linear PDOMA or PDOMA nanoparticles with minimized metal residues. The obtained PDOMAs were soluble in strong polar solvents and presented excellent light transmittance in a wavelength range of 314–800 nm (93%) and perfect ultraviolet (UV) absorption in a wavelength range of 200–313 nm (close to 100%), whilst most of the common polyacrylates cannot absorb UV light. In addition, the PDOMAs had tunable number-average molecular weights (Mns) of 12.0–132.0 kg mol−1 and high glass transition temperatures (Tgs) of 121.0–140.4 °C. Such CO2-based PDOMAs could be potentially used as wavelength-specific UV-absorbing materials. This work provides a simple and useful synthetic path to directly utilize CO2 by combining two reaction mechanisms.