Preparation And Properties Of Phosphorus- Nitrogen-containing Curing Agent And Its Application In Intrinsic Flame Retardant Epoxy Resin

Epoxy resin(EP)as one of the most important polymer materials,has been widely used in transportation,electronics,paints and coatings,adhesives and other fields owing to its excellent mechanical properties,chemical resistance,dielectric properties and dimensional stability.However,EP is a flammable material,which has a high calorific value and is accompanied by a large amount of smoke during combustion,causing serious harm to human life,property and the environment.Therefore,it is an urgent task to improve the flame retardancy of EP.In this thesis,three kinds of curing agents with flame retardant properties are designed and prepared.Based on this,intrinsic flame retardant EP are prepared through curing reaction.The specific research contents are as follows:1.A novel multifunctional organic-inorganic hybrid curing agent(AM-MEL)was prepared with nitrilotrimethylene triphosphonic acid and melamine modified magnesium hydroxide(MH)nanosheets,intrinsic flame retardant EP was obtained using AM-MEL as the curing agent.The structure and morphology of AM-MEL and intrinsic flame retardant EP were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and scanning electron microscope(SEM),the flame retardant properties of the prepared EP were investigated,and its flame retardancy and smoke suppression mechanism were studied.The results show that adding 5 wt% AM-MEL and 15 wt% APP,the limiting oxygen index value(LOI)of the prepared EP reaches 32.0%,and UL-94 reaches V-0 level.Compared with pure EP,the peak heat release rate(pHRR),total smoke production(TSP)and the peak CO production rate(pCOPR)were reduced by 88.0%,81.5% and 87.3%,respectively.2.A novel functionalized MH curing agent(HM-MEL)was prepared by reacting hydroxyl ethylenediaminic acid(HEDP)with nano-MH and then with melamine.The structure and morphology of HM-MEL and intrinsic flame retardant EP were characterized by FTIR,XPS and SEM,the flame retardant properties of the prepared EP were investigated.With the incorporation of 15 wt% HM-MEL into the EP,along with 53.5% and 53.2% decreased in the pHRR and the pCOPR,respectively,with respect to that of pure EP.3.A novel 2-methylimidazole zinc salt(ZIF-8)nanoparticle@polyphosphazene(PZN)core-shell structure was prepared.The chemical structure of ZIF-8@PZN was characterized by X-ray diffraction(XRD),XPS and transmission electron microscopy(TEM).Compared to pure epoxy,with the incorporation of 3 wt% ZIF-8@PZN and 18 wt% APP into the EP,along with 80.8%,72.6% and 64.7% decreased in the pHRR,the peak smoke production rate(pSPR)and the pCOPR,respectively.