Research On Functionalized MXenes Enhanced Thermal Stability Of Silicon Rubber

Silicon rubber（SR）is widely used in aerospace,electronics and many other high-temperature fields due to its special structure.In order to make silicone rubber work normally in a higher temperature environment,we can add heat resistance filler to improve thermal stability of silicone rubber.As a new two-dimensional material in recent years,MXenes has excellent thermal stability and a large number of abundant functional groups,which provides many possibilities for the combination of MXenes with other materials.However,there are very few studies and reports on the combination of MXenes as heat-resistant fillers with silicone rubber.Based on the above research,this paper uses room temperature vulcanized silicone rubber as raw material,and adds MXenes as heat-resistant fillers into silicone rubber by organicizing MXenes and using MXenes as a load respectively as a means of functionalizing MXenes.The influence of thermal stability and thermal conductivity of silicone rubber was investigated,and the mechanism of its thermal degradation process was explored using a variety of characterization methods.In this paper,polysilazane and MXenes were directly combined to prepare MP filler,which was added to silicone rubber as a heat-resistant filler.On this basis,we prepared MC fillers by carboxylating MXenes with chloroacetic acid.Using SEM,it was proved that carboxylated MXenes can solve the problem of compatibility between MXenes and silicone rubber,but only carboxylated MXenes and silicone rubber are compatible.There is no coupling between them,so on this basis,polysilazane and carboxylated MXenes are combined to prepare MCP filler and dope it into silicone rubber as a heat-resistant filler.The overall thermal stability of SR has been significantly improved.By means of XPS and the average molecular weight between cross-linking points,it was confirmed that the carboxylated MXenes can not only organically combine with polysilazane,but also effectively improve the compatibility between MXenes and silicone rubber.The reason for the improved thermal stability is that MXenes itself can inhibit the thermal motion of SR molecular chains,while the modified MCP can eliminate the SR terminal hydroxyl groups by chemical bonding while inhibiting the thermal motion of molecular chains,which inhibits the cross-linking of silicone rubber.The process of thermal degradation is advanced to the higher temperature intra-main chain rearrangement and inter-main chain rearrangement.In addition,through relevant test methods,it is proved that the thermal conductivity and dielectric constant of MCP/SR have been improved to varying degrees.According to the results of this study,MCP can be considered as an effective nanofiller,which can not only effectively improve the thermal stability of SR,but also form a good thermal conduction network in the molecular chain of silicone rubber,and can improve the dielectric performance.In addition,carboxylated MXenes were used as loading materials to support Fe₂O₃and Cu O,respectively,to prepare MFe and MCu.The thermal stability of MFe/SR and MCu/SR composites was investigated by TG.The results show that the thermal stability of MFe/SR and MCu/SR has been significantly improved compared with pure silicone rubber.The synergistic effect of MXenes with Cu O and Fe₂O₃was confirmed by XPS,average molecular weight between cross-linking points and FTIR.MFe and MCu can inhibit thermal degradation when the side chain of silicone rubber is degraded,and the macroscopic performance is that the thermal stability of the composite material is significantly improved...