Investigations of Flame-Retarded Poly(Imide−Urethane)s Containing Phosphorus Units

An attractive synthetic method to improve the properties, especially the flame retardant characteristics, is the utilization of monomers containing phosphorus, suchas 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) which possess a polar P=O group and a bulky structure. The introduction of DOPO groups into themacromolecular chains leads to polymers having improved flame retardancy, thermal oxidative stability, and solubility in organic solvents, good adhesion and lowbirefringence. The use of DOPO and its derivatives as flame retardants for polymers has been widely investigated due to its high thermal stability, good oxidation andhydrolysis resistance [1,2]. In the research, we would like to report a new method for the synthesis of flame retarded poly(urethane-imide) (PUI). Thermal, and flame retardant properties of nanocomposites was determined using suitable techniques such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) andlimiting oxygen index (LOI).