In this work, a new type of leaf‐shaped cobalt‐zeolitic imidazolate framework–modified graphene (Co‐ZIF‐L@RGO) hybrid was successfully prepared and blended with an intumescent flame retardant (IFR). It was added into thermoplastic polyurethane (TPU) to study the effect of its combination with IFR on the thermal conductivity and flame retardant performance of TPU. The morphology and structure of the Co‐ZIF‐L@RGO hybrid were characterized by scanning electron microscope (SEM), Fourier transform infrared and X‐ray diffraction (XRD). The results showed that Co‐ZIF‐L were uniformly loaded on the surface of graphene. Furthermore, compared with pure TPU, the limiting oxygen index values of the composite material with 3 wt% Co‐ZIF‐L and 27 wt% IFR increased to 32.6%. Their UL‐94 rating reached V‐0 rating. Their peak heat release rate, total heat release, peak smoke production rate and total smoke production were also greatly reduced by 84.4%, 70.1%, 60.3% and 62.5%, respectively. The thermogravimetric‐infrared test results showed that the amount of toxic gas emissions was effectively suppressed. The residual carbon was analyzed by SEM, laser Raman spectroscopy and XRD, and flame retardant mechanism was further investigated. Besides, the addition of this hybrid improved the thermal conductivity of TPU.

In this work, a new kind of co‐modified phenolic foam was synthesized with polyurethane prepolymer (PUP) and H3BO3 by a simple preparation method. Firstly, in order to determine the optimal amount of PUP, the effects of different PUP additions on the mechanical properties, foam microstructure, and pulverization rate of phenolic foam were investigated. Then H3BO3 was added to toughened phenolic foam, in order to reduce its fire hazard. The results showed that the mechanical properties of the PFPUP8 phenolic foam composite were the best when the PUP content was 8 wt%. It had a small and regular cell structure, and its pulverization ratio was reduced by 80% compared with that of pristine phenolic foam. Meanwhile, the flame retardant properties of PFPUP8 were improved in different degrees with an increase in the amount of H3BO3. Particularly, when the addition of H3BO3 was 10 wt%, the peak heat release rate, the total heat release, and the total smoke release values of PFPUP10B were decreased by 35.4%, 42.4%, and 45.2%, respectively, compared with those of PFPUP8. The value of the limit oxygen index was increased by 33.1%. Besides, the addition of H3BO3 had no adverse effect on the mechanical properties and pulverization ratio of PFPUP8. In addition, the specific mechanisms of toughening, flame retardant, and smoke suppression are also discussed in this paper on the basis of an investigation into the thermal properties of the toughened flame retardant foam composites by thermogravimetric analysis in N2 atmosphere.

A simple method was used to load zeolitic imidazolate frameworks (ZIFs) onto β-FeOOH nanorods to ameliorate the flame retardancy and smoke suppression of epoxy resin (EP). The morphology and structure of ZIF-8-β-FeOOH (Z8Fe) and ZIF-67-β-FeOOH (Z67Fe) nano hybrids were systematically characterized by field emission scanning electron microscope, Fourier transform infrared and Xray diffraction (XRD) spectra, which proved the successful preparation of the hybrids. 3 wt% of Z8Fe and Z67Fe were added to the EP matrix, and their combustion properties were studied, respectively. The results showed that the composites' limiting oxygen index values were ameliorated to 27.3% and 28.1%, respectively. Their UL94 flame retardant rating was improved, their peak heat release rate and total heat release were reduced, their flame retardant performance was considerably improved, and their generation of toxic smoke was significantly suppressed. Further, through X-ray photoelectron spectroscopy, XRD and laser Raman spectroscopy analysis of the char residue, their potential mechanism of flame retardancy and smoke suppression were studied.

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