Design And Syhthesis Of Bio-Based Polyurethane With Low Cost And Tunable Performance Via Two-Step Non-Isocyanate Route

Polyurethanes (PUs) have good comprehensive performance, but their raw materials are non-renewable and highly toxic, which greatly limit the application. Non-isocyanate polyurethanes (NIPUs) can stop the use of toxic isocyanate. However, subject to the high price of the monomer and the low comprehensive performance of linear NIPU, the total production of NIPUs is not very huge. This paper adopts a two-step way to synthesize NIPUs containing ester bonds, and the urethane bonds of the NIPUs are as many as ester bonds.The first step is to make ethylene carbonate with moderate price and yield react with different diamines to form a series of bis(hydroxyethyloxycarbonylamino)decane (BHD). The ends of BHD are two hydroxyl groups, and the urethane bonds existed in the BHD is symmetrical. The structure and purity of BHD are measured through nuclear magnetic resonance, infrared spectrum and mass spectrum analysis. The product BHD has great advantages, such as renewable raw materials, excellent thermal stability and high purity, which make BHD suit for the polyester reaction. The second step is the melt polyester polycondensation. BHD is reacted with different dicarboxylic acids to form a series of thermoplastic Poly-BHD-co-Dicarboxylic acids (PBDAs).The molecular weight of PBDAs distributes in 13900～28700 g/mol, and the glass transition temperature and the melting point distribute in 20.74～53.25℃ and 80.39～166.95℃ respectively. PBDAs have excellent mechanical properties, and the fracture stress distributes from 8.91 MPa to 17.95 MPa, and the elongation at break distributes from 32.09% to 223.09%. The water absorption and degradation in PBS solution of PBDAs are very low, and the weather resistance and the solvent (except acid and alkali solvent) resistance are excellent. Besides, PBDAs are environmental and partly renewable, which make them have a certain application prospect in engineering. A part of PBDAs have good biological compatibility because of micro-phase separation structure, which shows the certain medical application value.