A Review on CO₂‐Based Polyureas and Polyurea Hybrids

Abstract

The utilization of CO2 as a renewable and cheap carbon resource to produce fuels, chemicals and polymers has attracted more attention. This review will summarize the developments in the production of polymers like polyureas and polyurea hybrids with CO2 as a monomer directly or indirectly. The influences of catalyst and the structure of diamine monomer on the molecular weight, thermal stability and mechanical properties of polyureas are discussed. In addition, the general properties and applications of functional CO2‐based polyureas are also described. A few examples of CO2‐based polyurea hybrids are also introduced. Finally, the future research priorities as well as the development trend of polyurea materials are depicted.

Thermodynamic and Catalytic Insights into Non‐Reductive Transformation of CO2 with Amines into Organic Urea Derivatives

“…The first example introduced here is the comparable study on the phase effect of MnO 2 on the catalytic performance. [100] Among the four different phases (i. e., α-MnO 2 , β-MnO 2 , γ-MnO 2 , and δ-MnO 2 ) tested under the conditions that provided the conversion away from the equilibrium level, δ-MnO 2 exhibited the highest DBU yield (entries [23][24][25][26]. This δ-MnO 2 catalyst produced DBU in up to…”

“…Meanwhile, in the non-reductive conversion as drawn in Figure 1, CO 2 reacts with ammonia to produce urea ((NH 2 ) 2 CO; the annual production of urea from CO 2 is 112 million tons), [13,14] with alcohols to provide organic carbonates (not only small molecules but also polymers), [15][16][17][18][19][20][21] with alcohol and amine simultaneously to produce organic carbamates, [15,17,22,23] with amines to yield organic urea derivatives. [15,17,24] Among these valuable compounds, organic urea derivatives have a broad range of applications such as dyeing for cellulose fibers to act as antioxidants, corrosion inhibitors in gasoline, raw materials for pesticides, scavengers for aldehydes, and building blocks of medicines. [25][26][27][28][29] In all these cases, the oxidation state of the carbon atom in CO 2 is kept unchanged as + 4.…”

“…If the sustainable and mass production of hydrogen, namely so‐called “green hydrogen” via water electrolysis using renewable energy such as solar and wind, becomes possible, the reductive conversion of CO 2 is undoubtedly a powerful approach to utilizing CO 2 as a chemical source; yet, the development of such technology is still in progress. Meanwhile, in the non‐reductive conversion as drawn in Figure 1, CO 2 reacts with ammonia to produce urea ((NH 2 ) 2 CO; the annual production of urea from CO 2 is 112 million tons), [13,14] with alcohols to provide organic carbonates (not only small molecules but also polymers), [15–21] with alcohol and amine simultaneously to produce organic carbamates, [15,17,22,23] with amines to yield organic urea derivatives [15,17,24] . Among these valuable compounds, organic urea derivatives have a broad range of applications such as dyeing for cellulose fibers to act as antioxidants, corrosion inhibitors in gasoline, raw materials for pesticides, scavengers for aldehydes, and building blocks of medicines [25–29] .…”

Synthesis of Novel Nonisocyanate Poly(imide-urea)s from CO2-based Polyureas

“…18 The production of CO 2 -based PUas via the polycondensation of CO 2 with various diamines, including aliphatic, alicyclic, or aromatic types, has garnered significant attention in recent years. 3,17,19 Moreover, a range of CO 2based PUas, encompassing linear PUas, cyclic PUas, PUa thermoplastics, and PUa hybrids, have been prepared by a twostep method to get rid of undesired water. 17,20−26 Especially, the properties of the synthesized PUa could be elaborately controlled or adjusted by varying the molar ratio and chemical structure of diamines.…”

Nonsymmetric N-Substituted Polyureas from Ring-Opening Copolymerization of Aziridines and Isocyanates

“…Polyurea (PU) is a key industrial polymer, and its superior performance facilitates diverse applications including elastomers, fibers, foams, adhesives, and coatings. , Industrial PUs are commonly formed through polycondensation between polyisocyanate and polyamine, which does not require the use of catalysts or harsh reaction conditions. In the past few decades, developing alternative polycondensation route to PUs has been a hot topic: For example, in combination with polyamine, CO 2 , polycarbamate, and urea , were successfully used to produce PUs (Scheme a). Despite the building block along the PU backbone being highly tunable, conventional routes only give secondary (NH) urea linkages.…”