Zhuoran Zhang

The intumescent flame retardant (IFR) technique is an alternative to halogen-based flame retardants for reducing fire hazards in polymers. However, IFR has drawbacks like unsatisfactory flame-retardant efficiency and high loading requirements. In this study, MIL-125 (Ti-based metal–organic framework) is added to ABS/IFR composites to improve flame retardancy and reduce smoke emissions. Thermogravimetric analysis (TGA) results indicate that combining ammonium polyphosphate (APP) and expandable graphite (EG) increases charred residue and slows mass loss compared with the original ABS resin. The ABS/IFR/MIL-125 system stabilizes the char layer, serving as a protective shield against combustible gases during combustion. Additionally, MIL-125 enhances performance in microscale combustion calorimetry (MCC) flammability testing. In fire tests (UL-94, limiting oxygen index (LOI), and cone calorimeter), the ABS/IFR/MIL-125 system achieves a UL-94 V0 rating and the highest LOI value of 31.5% ± 0.1%. Peak heat lease rate (PHRR) values in the cone calorimeter are reduced by 72% with 20 wt.% of additives, and smoke production decreases by 53% compared with neat ABS. These results demonstrate the efficient synergistic effects of MIL-125 and IFR additives in improving the formation and stability of the intumescent char layer, thereby protecting ABS from intense burning.

Polystyrene (PS) is widely used in the plastics industry, but the application range of PS is limited due to its inherently high flammability. A variety of two-dimensional (2D) nanomaterials have been reported to impart excellent flame retardancy to polymeric materials. In this study, a 2D nanomaterial MXene–organic hybrid (O-Ti₃C₂) was applied to PS as a nanofiller. Firstly, the MXene nanosheets were prepared by acid etching, intercalation, and delamination of bulk MAX (Ti₃AlC₂) material. These exfoliated MXene nanosheets were then functionalized using a cationic surfactant to improve the dispersibility in DMF. Even with a small loading of functionalized O-Ti₃C₂ (e.g., 2 wt%), the resulting PS nanocomposite (PS/O-Ti₃C₂) showed good thermal stability and lower flammability evidenced by thermogravimetric analysis (TGA) and pyrolysis-combustion flow calorimetry (PCFC). The peak heat release rate (pHRR) was significantly reduced by 32% compared to the neat PS sample. In addition, we observed that the temperature at pHRR (T_pHRR) shifted to a higher temperature by 22 °C. By comparing the TGA and PCFC results between the PS/MAX and different weight ratios of PS/O-Ti₃C₂ nanocomposites, the thermal stability and 2D thermal- and mass-transfer barrier effect of MXene–organic hybrid nanosheets were revealed to play essential roles in delaying the polymer degradation.

With the rapid development of chemical process plants worldwide, the safe storage of hazardous chemicals continues to be an important topic. Chemical warehouse incidents related to fire and explosion are reported constantly. These incidents not only cause direct economic loss but also harm the local environment. Therefore, an accurate hazard identification method for a logistic warehouse is valuable since it can help people recognize the potential hazard in the chemical storage area. In this study, a storage hazard factor (SHF) was developed to evaluate and rank the inherent hazards of chemicals stored in logistic warehouses. In the calculation of SHF, the National Fire Protection Association (NFPA) hazard diamond was used to quantify the instability hazard; the U.S. Department of Energy’s Protective Action Criteria (PAC) values were utilized to modify chemical health hazard, and two machine learning based methods were used for the classification of flammability. The SHF and safety penalty factors (e.g., quantity, population density) were then utilized to create a hazard index of the facilities. This index can be used not only for developing a proper emergency response plan but also for effectively communicating risk with the residents who live near the facility. In addition, the index can be used by governments to allocate the resources better for first responders to make fire protection strategies, and by stakeholders to improve the risk management.