Design And Performance Study Of Flame-retardant Rigid Polyurethane Foam Based On Mxene And ?-aminophosphonate

Rigid polyurethane foam(RPUF)is a kind of thermal insulation material with excellent comprehensive performance.However,due to its porous structure and chemical composition,RPUF is highly flammable and will release a large amount of smoke particles and toxic gases during the combustion process,which seriously endangers people's lives and property.In view of the traditional flame retardant strategy,it is difficult to improve the fire performance of RPUF while taking into account its inherent mechanical properties,and the common organic phosphorus-nitrogen-based reactive flame retardant synthesis process is complex,low-efficiency,and environmentally friendly.This paper innovatively proposed based on intrinsic flame retardant and surface coating flame retardant "hybrid" strategy.Firstly,a simple,efficient,and environmentally friendly "one-pot" method is used to prepare the phosphorous and nitrogen-containing reactive flame retardant monomer ?-APP,and the?-APP/RPUF composite material is prepared by chemical reaction as the essential flame retardant matrix.Secondly,use MXene-PDMS as a nanocomposite flame-retardant coating to construct MXene-PDMS@?-APP/RPUF composite system.This strategy not only improves the flame retardant performance of RPUF,but also takes into account its inherent mechanical properties,this work provides a new idea and method to solve the flame retardant problem of RPUF..The main research work of this paper is as follows:(1)Firstly,this thesis adopts the method of comparison with MAX,through XRD,thermal oxidation behavior,CCT,SEM and other test methods,it fully reveals the flame retardant mechanism of MXene.This part of the work has perfected the flame-retardant mechanism of MXene in terms of its physical structure and chemical composition.(2)Secondly,the phosphorous-nitrogen-containing reactive flame retardant monomer?-APP was prepared by an efficient,simple and environmentally friendly “one-pot” method,and introduced into RPUF to obtain ?-APP/RPUF composite materials.Through UL-94,CCT and other tests,it is found that ?-APP will give RPUF a fast self-extinguishing function.Through ignition test,carbon layer,Raman and other test analysis,it has revealed the flame retardant mechanism of ?-APP: The gas phase flame retardant effect of ?-APP inhibits the spread of the combustion chain reaction;the phosphorus-nitrogen synergy of ?-APP promotes the rapid char formation of RPUF,and the surface charcoal layer insulates heat and flame from spreading inward to protect the internal matrix.(3)Finally,the ?-APP/RPUF with fast self-extinguishing function is selected as the essential flame retardant matrix of the "hybrid" flame retardant strategy,and then the MXene-PDMS nanocomposite flame retardant coating is constructed,and the MXene-PDMS coating is applied to the ?-APP/RPUF composite matrix surface forms MXene-PDMS@?-APP/RPUF composite system.The effects of different coating thicknesses on the structure,flame retardancy and mechanical properties of the composite system were studied.When the coating thickness is 1.5mm,the composite system reaches the UL-94 V0 rating,mainly due to the excellent heat insulation effect of the MXene-PDMS coating and the rapid self-extinguishing effect of the internal ?-APP/RPUF matrix.The "hybrid" flame retardant strategy not only improves the flame retardant properties of RPUF,but also takes into account its inherent mechanical and thermal insulation properties,and at the same time endows the surface of the substrate with hydrophobic properties.