Fabrication of hollow carbon spheres modified by molybdenum compounds towards toxicity reduction and flame retardancy of thermoplastic polyurethane

Abstract This article mainly studied novel hollow carbon microspheres modified with molybdenum compounds for flame retardancy and toxicity reduction in thermoplastic polyurethane (TPU) elastomer. The structure of hollow carbon spheres (HCS) was investigated by X‐ray photoelectron spectroscopy and scanning electron microscopy‐energy‐dispersive spectrometer, respectively. The specific molybdenum compounds on the surface of HCS were further investigated by X‐ray diffraction. The flame retardancy and toxicity reduction of hollow carbon microsphere in TPU composites were studied by cone calorimeter, thermogravimetric analysis, and Fourier transform infrared spectroscopy, and so forth. The result shows that HCS modified by molybdenum compounds (MOH) can reduce fire hazards and toxic release of TPU during combustion. For example, under the same load, the peak heat release rate of TPU/MOH composite decreased by 63.39%, that of TPU composite prepared by modified HCS with ammonium molybdate (TPU/AMH) decreased by 52.89%, and that of TPU composite prepared by introducing acidulated carbonized HCS (TPU/CAH) decreased by 40.73%, compared with that of pure TPU. The peak smoke production rate (pSPR), peak carbon monoxide production (pCOP), and peak carbon dioxide production (pCO 2 P) of TPU/MOH composite decreased by 52.34%, 72.4%, and 68.3%, respectively. Therefore, there is a novel strategy to incorporate modified HCS to TPU, facilitating its widely promising applications in TPU.