Flammability and thermal analysis of thermoplastic polyurethane/DOPO derivative/sepiolite composites

Thermoplastic polyurethane was an important polymer and widely used in many fields. However, poor fire performance significantly inhibits its further application. In this study, the flammability, thermal and mechanical properties of thermoplastic polyurethane (TPU)/DOPO derivative (DiDOPO)/sepiolite composites, fabricated by a melt blending process, were examined based on the sepiolite content. TPUSEP3 has achieved UL-94 V0 classes and LOI 34.4%. Micro-scale combustion calorimeter shows that TPU/DiDOPO/sepiolite composites possess an excellent fire performance. Flexural strength of TPUSEP3 has enhanced to 48.3 MPa which indicated the rigidity of composites has significantly improved. In addition, the scanning electronic microscopy images of the external surface of the carbon layer of composites show a very compact structure. Sepiolite and DiDOPO change the decomposition process of composites lead to the decrease of E a values of TPU/DiDOPO/sepiolite composites.