Thermal Stability and Flammability Studies of MXene-Organic Hybrid Polystyrene Nanocomposites

Zhuoran Zhang; Huaixuan Cao; Yufeng Quan; Rong Ma; Emily B Pentzer; Micah J Green; Qingsheng Wang

doi:10.3390/polym14061213

Thermal Stability and Flammability Studies of MXene-Organic Hybrid Polystyrene Nanocomposites

Polymers (Basel). 2022 Mar 17;14(6):1213. doi: 10.3390/polym14061213.

Authors

Zhuoran Zhang¹, Huaixuan Cao^{1

2}, Yufeng Quan¹, Rong Ma¹, Emily B Pentzer^{2

3}, Micah J Green^{1

2}, Qingsheng Wang¹

Affiliations

¹ Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA.
² Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA.
³ Department of Chemistry, Texas A&M University, College Station, TX 77843, USA.

Abstract

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.

Keywords: MXene; flammability; polymer nanocomposite; pyrolysis-combustion flow calorimeter; thermal stability.