Effect of organically intercalation modified layered double hydroxides-graphene oxide hybrids on flame retardancy of thermoplastic polyurethane nanocomposites

Flame retardant thermoplastic polyurethane (TPU) nanocomposites were prepared by melt blending using organically intercalation modified layered double hydroxides-graphene oxide hybrids (LDHs-GO). Modification process of LDHs-GO was carried out by using sodium dodecyl sulfate (SDS) in water/ethanol medium. X-ray diffraction, Fourier transform infrared spectra and scanning electron microscope micrograph results showed the SDS intercalation modified LDHs-GO (SDS-LDHs-GO) was synthesized successfully. Flame retardancy, suppression smoke and thermal stability properties of the well-dispersed TPU nanocomposites were evaluated and compared with each other. The CCT results showed that the pHRR was significantly decreased after incorporating SDS-LDHs-GO nanoparticles. In particular, the pHRR of the TPU5 containing 20 mass% SDS-LDHs-5%GO hybrid was decreased by 77.2% compared to that of pure TPU. The addition of SDS-LDHs-GO hybrids can enhance the suppression smoke performance of TPU nanocomposites as well, and the efficiency was dependent on the catalytic carbonization of lamellar LDHs and both the adsorption and barrier effect of GO. The TG results confirmed that GO can improve the thermal stability of nanocomposites by promoting char formation. This work provides a novel modification strategy for enhancing the dispersion and flame retardant efficiency of LDHs.