Poly(Urea-Urethane) Elastomers with Fire-Retardant and Tensile Properties Enhanced by a Built-In Phosphorus Derivative

One of the most popular materials used in the plastics industry is polyurethane (PUR). In recent years, these plastics have gained attention due to their ease of processing, their simple, relatively inexpensive manufacturing process, and, above all, their properties, which allow PURs to be used as rigid and flexible foams, flexible solid products, adhesives, and biomedical materials. The primary purpose of this work was to study the chemical and/or physical modifications of urethane prepolymers, resulting in enhanced mechanical properties and reduced flammability. A cross-linking agent based on triesters of phosphoric acid (PPEG) was synthesized and used as a component to produce PUR and poly(urea-urethane)s (PUUR). Commercially available polyether diols, with average molar masses of 450 and 2000 g·mol–1, and aromatic diisocyanates were used. In the further course of work, thermal properties, flammability, and selected mechanical parameters of the obtained materials were characterized. The addition of PPEG allowed one to achieve products exhibiting better tensile strength, up to 19-fold improvement in properties from 0.51 to 9.71 MPa, and increased thermal stability of materials. Moreover, the PPEG derivative has the ability to reduce the flammability of materials, which has been proven during tests on the calorimeter, where there is a decrease in the heat release capacity (HRC) and the peak heat release rate (peak HRR) compared to the unmodified PUR reference sample by 44.34 and 46.70%, respectively, for the material with the highest derivative content.