Functional Design,Structural Changes And Properties Of Ti₃C₂T_X MXene

Nowadays,polymer materials are widely used.Its combustible and catastrophic nature seriously threatens the safety of people’s lives and property.The aim of this project is to functionalize Ti₃C₂T_x and reduce fire risk in terms of fire warning and flame retardancy of polymers.The main research contents are as follows:1.The hydrogen bond/covalent bond interaction between PVA molecule and Ti₃C₂T_x was constructed to prepare Ti₃C₂T_x thermosensitive composite film and assemble a fire warning device.The PVA molecular chains are interspersed between the Ti₃C₂T_x layers,increasing the interlayer by 0.21 nm.Ti₃C₂T_x exhibited a stable and sensitive reversible fire cycle warning signal during flame attack,and the fire warning response and recovery time only required 2.2 s and 2.0 s,respectively.The fire warning mechanism of P-Ti₃C₂T_x was confirmed by XPS,XRD and TGA characterization methods.Oxygen-containing compounds（CO,CO₂,etc.）generated by the pyrolysis of PVA molecules promote the oxidation of Ti₃C₂T_x to form a C-doped Ti O₂ network,which generates thermally excited electrons and holes,and the electrons are excited from the valence band to the conduction band,thereby achieving a significant resistance transition.2.Based on the above experiments,it is found that the power supply of the current fire alarm device is fixed,flexible and adaptable.Considering small and convenient supercapacitors,they can be used as the preferred fire alarm device.Electrode materials are the key to the fabrication of high-performance supercapacitors.Diatomic co-doped SN-Ti₃C₂T_x and PN-Ti₃C₂T_x electrodes were prepared by doping modified Ti₃C₂T_x with guanidine sulfamate（GS）and guanidine phosphate（GP）.Guanidine salt doping enlarges the interlayer spacing of Ti₃C₂T_x and increases defects,which not only increases the accessibility and reactive sites of ions in the electrolyte,but also improves the conductivity of Ti₃C₂T_x.The electrochemical test results showed that at 1 A/g,the C_m of SN-Ti₃C₂T_x and PN-Ti₃C₂T_x was 269.3 F/g and 168.3 F/g,which were 2.03 and1.27 times that of Ti₃C₂T_x（132.6 F/g）,respectively.XPS can determine the specific way in which heteroatoms dop Ti₃C₂T_x.3.In addition to fire warning,the fire performance of the polymer itself is also particularly important.Studies have shown that the improvement of the fire resistance of polymers often compromises their mechanical properties.In order to solve this problem,this paper uses phytic acid（PA）and ferrous chloride tetrahydrate（Fe Cl₂·4H₂O）to chelate in situ on the surface of T_i3C₂T_x to obtain a hybrid filler（Fe-Ti₃C₂T_x）rich in phosphorus and iron.Fe-Ti₃C₂T_x is firmly combined with TPU through the formation of a large number of hydrogen bonds,thus showing strong interfacial compatibility,thereby realizing the dual improvement of TPU mechanical and fire resistance.This subject enriches the functional design of Ti₃C₂T_x from the perspective of solving practical problems.The fire warning device based on P-Ti₃C₂T_x thermally sensitive composite film avoids the problems of low sensitivity,high trigger threshold and irreversibility of GO alarm devices of traditional smoke alarms.Fe-Ti₃C₂T_x can also be used for the dual enhancement of mechanical and fire-resistant properties of other polymers,enriching the nanofiller category.Figure[48]table[8]reference[152]...