Preparation and relationship between structure and properties of PTMEG based polyurethane acrylate UV cured films

A series of polyurethane acrylate UV curing films (FPUA) were designed and prepared from three different hard segment structure, hard segment content and NCO/OH molar ratio via prepolymer process from polytetramethylene ether glycol(PTMEG), diisocyanate and polycaprolactone modified acrylate (FM1D). And the influence of structural parameters on the cured films' mechanical properties was studied; Besides, its thermal properties was characterized by Dynamic Thermomechanical Analysis (DMA) and Thermo Gravimetric Analyzer (TGA). Among these three hard segment structures, hexamethylene diisocyanate (HMDI) -based cured films have the best mechanical properties. The modulus and tensile strength of the cured films increases along with the increase of hard segment content, whereas the elongation at break of the cured films decreases since the rising of the NCO/OH molar ratio. Indeed, with hard segment content at 48.6% and NCO/OH molar ratio at 1.06, the UV cured films (exhibits the best performance)with tensile strength up to 50.5 MPa, and break elongation upto238%. DMA and TGA data showed that the low-temperature glass transition temperature of UV-cured films is around −50 °C, and the fastest thermal degradation temperature is 355 °C, showing good resistance to high and low temperatures.