Synthesis, Structure and Properties of Polyester Polyureas via a Non-Isocyanate Route with Good Combined Properties

Polyureas have been widely applied in many fields, such as coatings, fibers, foams and dielectric materials. Traditionally, polyureas are prepared from isocyanates, which are highly toxic and harmful to humans and the environment. Synthesis of polyureas via non-isocyanate routes is green, environmentally friendly and sustainable. However, the application of non-isocyanate polyureas is quite restrained due to their brittleness as the result of the lack of a soft segment in their molecular blocks. To address this issue, we have prepared polyester polyureas via an isocyanate-free route and introduced polyester-based soft segments to improve their toughness and endow high impact resistance to the polyureas. In this paper, the soft segments of polyureas were synthesized by the esterification and polycondensation of dodecanedioic acid and 1,4-butanediol. Hard segments of polyureas were synthesized by melt polycondensation of urea and 1,10-diaminodecane without a catalyst or high pressure. A series of polyester polyureas were synthesized by the polycondensation of the soft and hard segments. These synthesized polyester-type polyureas exhibit excellent mechanical and thermal properties. Therefore, they have high potential to substitute traditional polyureas.

Direct Synthesis of Polyurea Thermoplastics from CO2 and Diamines

The transformation of CO₂ into polymeric materials is an important and hot research topic from the viewpoint of renewable resources and environmental effects. Herein, a series of polyureas have been synthesized by polycondensation from CO₂ with diamines of 1,12-diaminododecane (DAD) and/or 4,7,10-trioxa-1,13-tridecanediamine (TTD). The properties of polyureas synthesized were characterized by FTIR, ¹H NMR, ¹³C NMR, XRD, DSC, TGA, and DMA. The polyureas synthesized from CO₂ with a mixture of diamines presented high performances compared to those of polyureas synthesized from CO₂ with a single diamine. The thermal and mechanical properties were improved largely by the variation in the crystallization and the chain flexibility depending on the changes in the density and/or intensity of hydrogen bonds. With increasing amounts of TTD from 0 to 100% in weight, the melting (T_m), crystallization (T_c), and glass transition (T_g) temperatures decreased from 207 to 116 °C, from 181 to 54 °C, and from 66 to -34 °C, respectively. When the TTD content was increased from 0 to 50 wt %, the Young's modulus decreased from 1170 to 406 MPa, and the tensile strength decreased from 53.3 to 42.9 MPa. However, the elongation at break increased from 13 to 330%. Furthermore, the chain length of aliphatic diamines and polyetheramines had a significant effect on the mechanical properties. The initial decomposition temperature (T_d,5%) is >295 °C, about 110 °C higher than the T_m (116-207 °C), which is advantageous for the postprocessing. The mechanical properties of the polyureas synthesized herein are superior to those of polycarbonate and polyamide 6. Thus, polyureas synthesized from the renewable and cheap resources, CO₂ and diamines, will find wide potential applications in the field of polymeric materials.

Transformation of CO2 into polyureas with 3-amino-1,2,4-triazole potassium as a solid base catalyst

The synthesis of polyureas from CO₂ and diamines with KATriz as the catalyst.

Synthesis of azo carbonate monomers and biocompatibility study of poly(azo-carbonate-urethane)s

The present study describes the synthesis of non-isocyanate poly(azo-carbonate-urethane)s and characterization by FT-IR, NMR, MALDI, GPC and TG. Biocompatible properties were investigated by the liver, kidney and colon histological analyses.

Utilization of carbon dioxide to build a basic block for polymeric materials: an isocyanate-free route to synthesize a soluble oligourea

A water soluble oligourea was synthesized by an isocyanate-free route from carbon dioxide and diamine through a green process, which may have wide applications in the macromolecule field as a building block.