Synthesis And Properties Of Flame Retardant Epoxy Resin

Epoxy resins are one of the most significant thermoset polymers contributing better thermal and mechanical properties,chemical resistance and adhesion.Owing to these exceptional properties,epoxy resins are utilized for various applications such as paintings,coatings,insulation materials,composites and constructions.However,the flammability is one of the main drawbacks to restrict its applications in many areas involved in transportation,construction,and electric and electronic industries.As a possible solution to this problem,in this thesis,a synergistic flame retardant of phosphorus,nitrogen and silicon and a synergistic flame retardant of boron and nitrogen were synthesized and used as additives into epoxy resin.Resveratrol based epoxy resins were also designed and prepared.This thesis is constituted of three parts.1.Using hexachlorocyclotriphosphazene,KH550,and aniline as the main raw materials,a phosphorus,nitrogen,and silicon trifunctional synergistic flame retardant was synthesized by a one-pot method,then Fourier transform infrared spectroscopy(FT-IR)and hydrogen nuclear magnetic resonance spectrum(1H-NMR)were utilized to confirm its molecular structure.It was added to epoxy resin,and its flame retardant properties were studied by using Thermal gravimetry Analysis,Limiting Oxygen Index,Smoke Densitometer,Micro Calorimeter,and Horizontal Vertical Flame Tester.Scanning electron microscope(SEM)studys its residual carbon morphology.When the added amount of flame retardant reaches 7%,the limiting oxygen index can reach a maximum of 27 5%,the vertical combustion grade reaches V-1 grade,and the smoke density grade drops to 61.7.In addition,the surface-modified nmSiO2 is added,and the flame retardancy of the epoxy resin has been further improved.2.A novel boron-nitrogen synergistic flame retardant was synthesized by using 4-carboxyphenylboronic acid and thionyl chloride as the main raw materials,using Fourier transform infrared spectroscopy(FT-IR)and hydrogen nuclear magnetic resonance spectroscopy(1H-NMR)to characterize Its structure.The flame retardant was added to the epoxy resin in different proportions,and the flame retardancy were studied using thermal gravimetry analysis,limiting oxygen index,smoke density tester,microcalorimeter,and horizontal vertical flame tester.Scanning electron microscope(SEM)was used to study the morphology of its carbon residue.The study found that only 3%of the added amount,the smoke density grade can be reduced to 65.7,and with the further increase of flame retardant,the limiting oxygen index reaches a maximum of 27.9%,and the total heat release and maximum heat release rate are founded significantly lower.3.A novel bio-based epoxy monomer was synthesized using resveratrol and epichlorohydrin as the main raw materials.Indoleamine was used as the main raw material to synthesize a bio-based curing agent that was mixed and cured under heating conditions,and the influence on the performance of final product under different raw material ratios was discussed.A kind of epoxy resin with excellent flame-retardant properties,which does not require the addition of any flame-retardant elements,has a limiting oxygen index of 52.5%,which is self-extinguishing from the fire.